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ACE9040
Audio Processor Advance Information
Supersedes January 1997 edition, DS4289 - 2.5 DS4289 - 3.1 December 1997
ACE9040 provides all the speech signal processing and data/SAT tone filtering needed for AMPS or TACS analog cellular telephones. Transmit voice channel functions comprise a microphone amplifier, soft limiter, bandpass filter, compressor, hard limiter, lowpass filter and a gain controlled amplifier to set deviation level. Additional transmit circuits include a DTMF generator, data and SAT filters, deviation setting amplifiers for data/ST and SAT and a modulation combiner. ACE9040's receive path comprises a bandpass filter, expander, volume control and power amplifiers to directly drive an earpiece or handsfree transducer. Gain settings, mute switches and filter characteristics are programmed via a three wire serial interface. To implement a handsfree function, both transmit and receive paths have rectifiers for signal amplitude monitoring via an external pin and signal path attenuators controlled via the serial interface. ACE9040 combines minimum power consumption with low external component count. Standby modes greatly reduce supply current and extend battery charge intervals.
AMPO DTMF nc V485 BGAP TLPO SUMI
SUMO MOD AVSS DATO
nc AMPI PREIN TBPO CIN CRCIN VMIDTX CRCOUT nc COUT TXC RXC IPS SLO MI MICBIAS
TSO RSO SD SCLK LVN
ACE9040
1
RBPO EAMPI HFGIN EOUT ERCIN VDD DEC HF LI RREF BIAS AVDD DATI TSI RSI RXI
nc\DVSS* nc\LEN* DVSS\DVDD* LEN\VMIDRX* DVDD\LO* VMIDRX\STBY* LO\EVDD* STBY\EPON* EVDD\nc* EPON\nc* EVSS EPOP EAMPFB EAMPO EIN ERCOUT
FP64 FP64
FEATURES s Low Power and Low Voltage (3*6 to 5*0 V) Operation
s s s s s s s s s Power Down Modes Direct Connections to Microphone and Earpiece Compander with wide operating range: Compressor 74 db typ., Expander 36 dB typ. SAT Bandpass and Data Lowpass Filters Handsfree Operation Supported DTMF Generator Serial Bus Controlled Gains and Filter Responses Part of the ACE Integrated Cellular Phone Chipset TQFP 64 Pin 10X10 mm or 7X7 mm Packages
Note: Pin 1 is identified by moulded spot and by coding orientation. (* 7 x 7 mm package and 10 x10 mm package pinouts on page 3)
Fig.1 Pin connections - top view
ABSOLUTE MAXIMUM RATINGS
Supply voltage Storage temperature Operating temperature Voltage at any pin 6V - 55 C to + 150 C - 40 C to + 85 C - 0.3 V to VDD + 0.3 V
MI AMP
COMPRESSOR
FILTERS AND DEVIATION SET
TLPO
APPLICATIONS s AMPS and TACS Cellular Telephones s Two-Way Radio Systems RELATED PRODUCTS
ACE9040 is part of the following chipset: s ACE9020 Receiver and Transmitter Interface s ACE9030 Radio Interface and Twin Synthesiser s ACE9050 System Controller and Data Modem
SUMI DTMF DTMF GEN. MODULATION SUMMING AMPLIFIER SUMO MOD DATI DATA FILTER (LOW PASS) DATO SET DEVIATION FEEDBACK
TSI
TX SAT FILTER SET LEVELS
GENERATE/ TRANSPOND
TSO
RSI
RX SAT FILTER
RSO
ORDERING INFORMATION
Industrial temperature range TQFP 64 lead 10 x 10 mm, 0*5 mm pitch ACE9040K/IW/FP1N - devices shipped in trays and dry packed ACE9040K/IW/FP1Q - tape mounted and dry packed TQFP 64 lead 7 x 7 mm, 0*4 mm pitch ACE9040K/IW/FP2N - devices shipped in trays and dry packed ACE9040K/IW/FP2Q - tape mounted and dry packed
RXI RX FILTER EXPANDER VOLUME SCLK LEN SD CONTROL LOGIC
EPOP
EPON LO LINE OUTPUT
STBY
Fig. 2 ACE9040 Simplified Block Diagram
DEC 3.3F BIAS RREF MICBIAS 100/ BGAP 68*k 10nF HANDSFREE RECTIFIER
BIAS GENERATOR
2
100nF 82nF 33nF 10nF EOUT HFGIN EAMPI EAMPFB 13 1 SUB 21 23 EPOP EPON 24 7 28 RXLEVEL EARSENSE _ + VMIDRX SIDETONE LODRIVE EPH0/EPH1 26 HIZ 38 60 50 _ + VMIDTX 36 37 SCHMITT SD SATS -15dB SATDEV VMIDRX DTMF MODE HANDSFREE RECTIFIER RXC HFS TXC TXSENSE _ + VMIDTX 40 3 59 34 35 TEST [1:0] SERIAL INTERFACE PREEMPHASIS TEST [2:1] TXBPF INPSENSE 62 SLO IPS 10nF 61 HFGAIN 52 53 56 54 TBPO CIN CRCOUT CRCIN 10nF 180k 100nF 55 58 51 COUT PREIN 82nF 33nF 39 AVSS 30 45 DVSS V485 22 EVSS COMPRESSOR GAIN CONTROL HARD LIMIT -8 dB TXLPF TLPO AUDIODEV VMIDTX DRIVER 29 25 3 & 97% DETECT LEVELS TEST [1:0] 92% DETECT LEVEL DTMFM MOD HF TXC 68nF SCLK SD LEN STBY TEST[0] 42 SUMI 41 48 LO DATO EPH0/ EPH1 EAMP HFATTEN 20 19 27 14 15 EAMPO VDD EVDDAVDD DVDD RBPO EIN ERCOUT ERCIN 12 RXM RXBPF EXPANDER EXPGAIN COMP[2:1] DATADEV VMIDRX 18 16 17 150 64 33F RXC 68nF AMPI AMPO RSO TSO SUMO TXM 43 TLPO
ACE9040
180K
RXI
11
TONEM
10nF
DATI
8
DATM
LOW PASS FILTER
VMIDRX
VMIDRX
2 6 5 64 44
VMIDTX
*VDD = 3.75V
RSI
10 RXSAT FILTER
10dB
TSI
9
TXSAT FILTER
Fig. 3 ACE9040 Detailed Block Diagram
-12 dB / 0 dB
DTMF
PREEMPHASIS
VDO
DTMF 220 k
47
LVN
33
_
Vth
+
VDD
LI
4
MLI
MIS
MI
SOFT LIMITER
63
ACE9040
PIN DESCRIPTIONS
Pin No. Pin No. Name FP2 package FP1 package Description
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31/32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23/24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64
VDD DEC HF LI RREF BIAS AVDD DATI TSI RSI RXI RBPO EAMPI HFGIN EOUT ERCIN ERCOUT EIN EAMPO EAMPFB EPOP EVSS nc EPON EVDD STBY LO VMIDRX DVDD LEN DVSS nc LVN SCLK SD RSO TSO DATO AVSS MOD SUMO SUMI TLPO BGAP V485 nc DTMF AMPO nc AMPI PREIN TBPO CIN CRCIN VMIDTX CRCOUT nc COUT TXC RXC IPS SLO MI MICBIAS
VDD supply to substrate, pin should be at highest d.c. voltage Mid-supply reference decoupling connection, 3.3 F to GND Output from TX or RX handsfree rectifier, switched by bit "HFS" Line input Reference bias current set for all op-amps by resistor to GND Buffered mid-supply reference output Analogue VDD input Transmit data input SAT path input for locally generated tone SAT path receiver input for received tone Speech path receiver input Audio output from EXPGAIN block Output from EARSENSE amp Input to RX volume control and handsfree attenuator Expander speech output Expander time constant input, 180 k to ERCOUT, 100 nF to GND Expander time constant output, 180 k to ERCIN Expander speech input, 33 nF to RBPO Output from EAMP op-amp Inverting input to EAMP op-amp Earpiece driver positive output Earpiece VSS (GND) supply connection No connection Earpiece driver negative output Earpiece VDD supply input Standby output: low indicates standby state, high is VDD output @ 10 mA Line output RX path mid-supply reference voltage, 82 nF to GND Digital VDD Serial interface latch signal input, rising edge triggered Digital VSS (GND) connection No connection Low supply VDD voltage indicator comparator output, reset active low output Serial interface system clock input Serial interface data input Received (regenerated) SAT output Transmit SAT output, regenerated or transponded Transmit data filter output. Analogue VSS (GND) Modulation output: sum of Speech, Data and SAT Modulation summing amplifier output Modulation summing amplifier input Transmit audio lowpass filter output Bandgap voltage output, 10 nF to GND Hard limiter gain selection for 3.75 V or 4.85 V nominal supplies No connection DTMF tone output Auxillary op-amp output No connection Auxillary op-amp inverting input (non-inverting internally connected to VMIDTX) Transmit pre-emphasis filter input Transmit bandpass filter output Compressor audio input, 10 nF from TBPO Compressor time constant input, 100 nF to GND, 180 k to CRCOUT TX path reference voltage, 82 nF to GND Compressor time constant output, 180 k to CRCIN No connection Compressor audio output, 33 nF to PREIN Transmit handsfree audio level sensing rectifier smoothing filter, 68 nF to GND Received handsfree audio level sensing rectifier smoothing filter, 68 nF to GND Transmit audio gain INPSENSE adjustment block input Soft limiter output Microphone input Bias for electret or active microphone
Note: FP1 = 10 x 10mm package, FP2 = 7 x 7 mm package
3
ACE9040
ELECTRICAL CHARACTERISTICS
These characteristics are guaranteed over the following conditions unless otherwise stated (Note 1): TAMB = - 40 C to + 85 C, VDD = 3.6 V to 5.0 V Characteristic Symbol Min. Supply Current and Power Down Modes Operating supply current IDD Standby Attenuation of all inputs signals Wakeup response time Sleep (Standby with CLK stopped) Supply current* IDD(SLEEP) Delay between setting STBY bit and stopping clock Delay to starting clock after wakeup Value Typ. 15 15 40 10 200 20 100 Unit Max. mA mA dB ms A s s STBY bit set VDD = 3.75 VDD = 4.85 V RREF = 100 k VDD = 3.75 V RREF = 68 k Conditions
* Standby current measured with the 1.008 MHz clock stopped and SCLK at a level <200 mV.
Characteristic Min. Transmission Path Microphone Amp, MI to SLO pins Input bias Microphone input gain (LO) Microphone input gain (HI) Microphone crosstalk (no MI signal) Line input, LI to SLO pins Input bias LI input Gain (0dB) LI input Gain (LO) LI input gain (HI) LI input crosstalk (no LI signal) Soft Deviation Limiter, LI to SLO pins Nominal gain Attenuation range Attenuation steps Distortion Attack level:Hard limiter output Attack level at TBPO pin Attack time Decay time INPSENSE Gain Stage, IPS to TBPO pins Nominal gain 7.5 Gain adjustment range Gain step size - 12 0.6
Value Typ.
Unit Max.
Conditions
21 31
VDD/2 22 32
23 33 - 40
dB dB dB
Internal 150 k bias resistor to VDD/2 MIS = 1, MLI = 0, MIG = 0 MIS = 1, MLI = 0, MIG = 1 MIS = 1, MLI = 0, MIG = 1 Internal 100 k bias resistor MIS = 0, MLI = 0, MIG = 0 MIS = 1, MLI = 1, MIG = 0 MIS = 1, MLI = 1, MIG = 1 MIS = 1, MLI = 1, MIG = 1 Limiter not functioning.
VDD/2 - 0.5 21 31 22 32 0.5 23 33 - 40 dB dB dB dB dB dB dB
%THD
0 - 30 0.27 3 92 40 1.68 8 8.5 12.8 0.8 1.2 0.5 - 29 0.67 2 97
Output at 1 Vrms d.c. input at IPS TEST[1:0] = 11 Per gain step when signal outside threshold Per gain step Input = 100 mVrms, INPS[4:0] = 15, THF = 0 dB, Relative to nominal gain Input = 100 mVrms, INPS[4:0] = 0 to 31, THF = 0 dB
% VDD % VDD s ms dB dB dB
Note 1. 100% production tested at 25 C but guaranteed over specified temperature range.
4
ACE9040
ELECTRICAL CHARACTERISTICS
These characteristics are guaranteed over the following conditions unless otherwise stated (Note 1): TAMB = - 40 C to + 85 C, VDD = 3.6 V to 5.0 V Characteristic Min. TX Audio Bandpass Filter TXBPF, IPS to TBPO Noise Distortion Frequency response relative to 1040 Hz - 60.5 - 25.5 - 1.0 - 0.5 - 0.5 - 1.5 - 3.0 - 10.5 - 20.5 - 90.5 TX Handsfree Gain Stage HFGAIN Nominal gain Gain range - 52.5 Gain step size 6.5 Gain step size 5 TX Compressor Stage, CIN to COUT pins Unity gain level 636 Input range 0.79 Linearity CIN to COUT: (Deviation from 2:1 I/O relationship) Attack time Decay time Distortion Frequency response TX Pre-emphasis, PREIN to TLPO pins Input impedance Internal compressor and BAR: Nominal gain TACS Nominal gain AMPS External compressor and bypass: Nominal gain AMPS & TACS Frequency response Value Typ. Unit Max. - 72 1 - 38.5 - 10.5 + 0.5 + 0.5 + 0.5 - 0.5 - 1.5 -5 - 15.5 - 30.5 0 - 49 7 7 707 dBV %THD dB dB dB dB dB dB dB dB dB dB dB dB dB dB mVrms mVrms dB ms ms 2 0.2 75 - 7.5 - 11.5 - 0.5 5.8 -7 - 11 0 6 - 6.5 - 10.5 + 0.5 6.2 %THD dB k dB dB dB dB/ Octave COMP[2:1] = 10 or 01 at 1 kHz Conditions
1 Vrms output f = 60 Hz f = 184 Hz INPSENSE = 0 dB f = 430 Hz THF = 0 dB f = 676 Hz, 1040 Hz f = 1410 Hz, 1900 Hz f = 3260 Hz f = 3500 Hz f = 4120 Hz f = 5590 Hz f = 9900 Hz
- 45.5 7.5 9 777 1000 0.5
THF[2:0] = 0 to 7 0 to -21 dB -28 to -49 dB = Vref (Unaffected level) CIN = Vref + 3 dB to Vref - 59 dB BW = 300 Hz to 3.4 kHz 12 dB step: - 8 dB to - 20 dB relative to the unity gain (Vref) level Attack & Decay levels = 1.5 and 0.75 of steady state final value BW = 300 Hz - 3.4 kHz BW = 300 Hz - 3.4 kHz
3 13.5
COMP[2:1] = 11 or 00 at 1 kHz TEST[1:0] = 01 PREEMPH = 0 (active) f = 300 to 3400 Hz
5
ACE9040
ELECTRICAL CHARACTERISTICS
These characteristics are guaranteed over the following conditions unless otherwise stated (Note 1): TAMB = - 40 C to + 85 C, VDD = 3.6 V to 5.0 V Characteristic Min. 13 15.5 Low Pass Filter TXLPF, PREIN to TLPO pins Distortion Noise Frequency response TACS/AMPS 0.3 Relative to 1 kHz - 0.5 - 0.5 - 3.0 - 38.0 - 60.0 - 60.0 - 60.0 - 60.0 - 60.0 Gain - 8.5 Attenuation with TXLPF bypassed Gain Stage AUDIODEV, PREIN to TLPO Nominal gain Gain adjustment - 2.8 Attenuation step size 0.2 TXM switch attenuation Combined TX path Gain with 3.5 V at Microphone input 33.5 Distortion Noise Output d.c. level 1.65 Hard Deviation Limiter Gain Value Typ. 13.5 16 Unit Max. 14 16.5 1.5 - 60 0.7 + 0.5 + 0.5 - 1.5 - 13.0 - 38.0 - 38.0 - 38.0 - 35.0 - 35.0 - 7.5 dB dB %THD dBV dB dB dB dB dB dB dB dB dB dB dB dB dB dB dB dB dB % THD dBV V V485 pin = 0 V (for VDD = 3.75 V) V485 pin = VDD (for VDD = 4.85 V) 1.5 Vp-p Output level BW = 30 Hz to 30 kHz f = 307 Hz f = 676 Hz, 1040 Hz f = 1410 Hz, 1900 Hz f = 3010 Hz f = 3500 Hz f = 4120 Hz f = 5590 Hz f = 9900 Hz f = 11870 Hz f = 14950 Hz TEST[0] = 1 Output at TLPO Control bits: AUDEV[3:0] AUDIODEV = 0 dB INSENSE = 0 dB, V485 = 0 V THF & AUDIODEV = 0 dB MI gain = 22 dB, VDD = 3.6 V Compressor Bypassed Conditions
-
-8 8 0 0.4
3.2 0.6 - 60 37.5 1.0 - 55.0 1.9
6
ACE9040
ELECTRICAL CHARACTERISTICS
These characteristics are guaranteed over the following conditions unless otherwise stated (Note 1): TAMB = - 40 C to + 85 C, VDD = 3.6 V to 5.0 V Characteristic Min. Receive Path RX Input stage RXSENSE, RXI to RBPO pins Input bias Nominal gain 7.25 Gain adjustment range -6 Gain adjustment step size 0.2 RX Audio Bandpass Filter RXBPF Gain Distortion Noise Frequency Response - 90.0 Relative to 1040 Hz - 15.0 - 2.0 - 0.5 - 0.5 - 3.0 - 10.0 - 40.0 - 40.0 - 90.0 RXM mute switch attenuation Rx Internal Expander Gain EXPGAIN: internal external and bypass Unity gain level Linearity EIN to EOUT (Deviation from 2:1 input/output) Distortion Frequency response Attack time Value Typ. Unit Max. Conditions
VDD/2 8 0.4 0
Internally biased to VDD/2 by 150 k 8.75 6.4 0.6 dB dB dB dB %THD dB dB dB dB dB dB dB dB dB dB dB dB Input 40 mVrms at RXI RXM = 1, RXSENSE = 0 to 31
1 - 65 - 45.0 - 7.0 + 0.5 + 0.5 + 0.5 - 0.5 - 6.0 - 25.0 - 25.0 - 40.0 - 40
At 1 kHz with 40 mVrms input BW= 30 Hz to 30 kHz f = 60 Hz RXSENSE = 0 dB f = 184 Hz COMP[1:0] = 00 f = 430 Hz f = 676 Hz, 1040 Hz f = 1410 Hz, 1900 Hz f = 3260 Hz f = 3500 Hz f = 4120 Hz f = 5590 Hz f = 9900 Hz Output switched to VDD/2 when muted. COMP[2:1] = 10 COMP[2:1] = 00 or 11 = Vref (Unaffected level) EIN = Vref to Vref - 33 dB BW = 300 to 3400 Hz 1 Vrms 300 to 3400 Hz 6 dB step (- 4 dB and -10 dB) relative to the unity gain (Vref) level at 1 kHz to pin EIN. Output at EOUT. Attack and delay time levels = 0.57 and 1.5 of final steady state value. RXV[2:0] = 3, RHF = 0 dB RXV[2:0] = 0 to 7 EARSENSE = 0 dB, Sidetone = 0 dB RHF, RVX, EARSENSE = 0 dB, SD =0 RHF[2:0] = 0 to 7 0 to - 21 dB - 28 to - 49 dB RVX = 0 dB, RHF = 0 dB, HIZ =1 1.0 Vrms output HIZ = 0 BW = 30 Hz to 30 kHz VDD = 3.6 V
11.8 850
12.3 0 1000
12.8 1100 1 2 0.2
dB dB mVrms dB %THD dB ms
3
Decay time RX Volume Control RXLEVEL Nominal Gain Gain adjustment range Gain adjust step size RX Handsfree Gain Stage HFATTEN HFGAIN to EAMP nominal gain Gain range Gain control step size Gain control step size RX Line Driver LODRIVE LO gain Distortion LO mute Noise LOoutput during mute
13.5
ms
- 11 -9 2 - 0.4 - 52.5 6.5 5 4 - 40 1.5
- 12 3 0 - 49 7 7 5
- 13 12 4 0.4 - 45.5 7.5 9 6 2 - 80 2.1
dB dB dB dB dB dB dB dB %THD dB dBV V
VDD/2
7
ACE9040
ELECTRICAL CHARACTERISTICS
These characteristics are guaranteed over the following conditions unless otherwise stated (Note 1): TAMB = - 40 C to + 85 C, VDD = 3.6 V to 5.0 V Characteristic Min. Rx Earpiece Gain Adjustment EARSENSE Nominal gain Total gain - 2.8 Gain adjustment step size 0.2 Distortion Rx Sidetone Path, IPS to EAMPI Attenuation at EARSENSE amp input 18 Sidetone mute Rx Earpiece Drivers EPOP & EPON EPON single ended gain 5.5 EPOP single ended d.c. level EPOP single ended a.c. level EPON single ended distortion EPON & EPOP differential gain EPOP differential distortion Earpiece mute switch attenuation EPON external mode: EPON gain relative to EAMPI EPON distortion EPOP output current external mode EPON & EPOP mute EPOP Noise Transmit Data Path TX Data Filter 16 kHz & 20 kHz Input bias at DATI Nominal gain Distortion Noise DATM mute switch attenuation Data Filter frequency response 16 kHz (TACS) 1.7 Value Typ. 0 0.4 3.2 0.6 1 20 - 40 6.5 1.9 - 20 1 12.5 1 Unit Max. dB dB dB % THD dB dB dB V dB % THD dB %THD dB dB % THD A dB dBV Conditions
EARS[3:0] = 0 to 15 RVX = 0 dB, RHF = 0 dB, SD = 0 Output 1 Vrms EARSENSE = 0 dB SD = 0 Output = 2 Vpp, 120 EPON to EPOP VDD = 3.6 V, EPH1 = 1, EPH0 = 0 Output = 2 Vpp 150 ( 20 %) EPON to EPOP Output = 4 Vpp, EPH1 = 1, EPH0 = 1 EPH0 = 0 & EHP1 = 0 64 ( 20 %) + 3.3 F to GND, EAMPFB open, Input = HFGIN Output = 1.1 Vpp At VDD & 0 V EPH1 = 0, EPH0 = 0 EPH1 = 1, EPH0 = 1
19
6 VDD/2
11.5 40 5.5 - 10
12
6.5 1 10 - 40 - 80
VDD/2 - 6.5 -6 - 5.5 1.5 -60
V dB %THD dBV dB dB dB dB dB dB dB dB dB dB dB dB
Internally tied via 800 k resistor to VDD/2. Input = 1 Vrms Output = 1.5 Vp-p BW = 30 Hz to 30 kHz
40 - 0.3 - 0.3 - 0.1 - 0.9 - 2.5 - 5.0 - 5.0 - 6.0 - 7.0 - 11.0 - 12.0 0.3 0.3 - 0.7 - 1.6 - 1.5 - 2.0 - 3.0 - 4.0 - 5.0 - 9.0 - 10.0
f = 676 Hz, 1040 Hz f = 4120 Hz f = 12120 Hz f = 13960 Hz f = 14950 Hz DATM = 1 f = 16050 Hz DATADEV = 0 dB f = 16420 Hz Relative to 1040 Hz f = 17040 Hz DATAF[1:0] = 10 f = 18020 Hz f = 19990 Hz f = 20970 Hz
8
ACE9040
ELECTRICAL CHARACTERISTICS
These characteristics are guaranteed over the following conditions unless otherwise stated (Note 1): TAMB = - 40 C to + 85 C, VDD = 3.6 V to 5.0 V Value Min. Typ. TX Data Filter 16 kHz & 20 kHz (continued) Data Filter frequency response 20 kHz (AMPS) - 0.3 - 0.3 - 0.3 - 2.5 - 3.0 - 4.0 - 5.0 - 5.5 - 7.0 - 8.0 - 10.0 TX Data Gain Stage DATADEV, DATI to DATO pins Nominal gain 0 Gain adjustment - 2.8 Gain adjustment steps 0.2 0.4 TXSAT and RXSAT Bandpass Filters 6 kHz RXSAT Filter RXSAT gain 9 Characteristic Unit Max. Conditions
0.3 0.3 - 1.5 - 1.0 - 1.5 - 2.0 - 3.0 - 3.5 - 5.0 - 6.0 - 8.0
dB dB dB dB dB dB dB dB dB dB dB dB dB dB
f = 676 Hz, 1040 Hz f = 4120 Hz, 16050 Hz f = 16050 Hz f = 18020 Hz f = 18880 Hz DATAF[1:0] = 11 f = 20240 Hz DATM = 1 f = 20540 Hz DATADEV = 0dB f = 20970 Hz Relative to 1040 Hz f = 21960 Hz f = 22820 Hz f = 24050 Hz
3.2 0.6
DATD[3:0] = 7 DATM = 1 DATAF[1:0] = 00
11
dB
RXSAT 6 kHz frequency response
RSO Schmitt output
- 90.0 - 90.0 - 90.0 - 29.0 - 0.30 - 0.10 - 0.10 - 0.30 - 26.5 - 90.0 - 90.0 - 90.0 5.5
6.0
- 35.0 - 35.0 - 35.0 - 24.0 0.50 0.35 0.35 0.50 - 22.0 - 29.0 - 35.0 - 35.0 6.5
dB dB dB dB dB dB dB dB dB dB dB dB kHz
Input = 400 mVrms at 6030 Hz, SATDEV = 0 dB, SATM = 1, SATS = 0dB f = 2520 Hz Relative to 6030 Hz f = 3500 Hz SATS = 0 dB, f = 4120 Hz TACS = 1, f = 4980 Hz SATD = 15 (0 dB), f = 5900 Hz SATM = 1 f = 5960 Hz f = 6030 Hz f = 6090 Hz f = 7010 Hz f = 8060 Hz f = 9040 Hz f = 9290 Hz SATS = 0 dB, TACS = 1
9
ACE9040
ELECTRICAL CHARACTERISTICS
These characteristics are guaranteed over the following conditions unless otherwise stated (Note 1): TAMB = - 40 C to + 85 C, VDD = 3.6 V to 5.0 V Characteristic Min. TXSAT Filter 6 kHz TXSAT gain TXSAT 6 kHz frequency response - 29.0 - 90.0 - 90.0 - 90.0 - 29.0 - 0.30 - 0.10 - 0.10 - 0.30 - 26.5 - 60.0 - 60.0 - 80.0 Value Typ. Unit Max. - 25.0 - 35.0 - 35.0 - 35.0 - 24.0 0.50 0.35 0.35 0.50 - 22.0 - 35.0 - 35.0 - 35.0 - 71.0 0 - 4.5 0.05 40 60 85 5 - 40 5 - 40 0.5 2.5 0 0.4 0.5 3.2 0.6 2 - 80 0.3 4.8 0.55 2 dB dB dB dB dB dB dB dB dB dB dB dB dB dBV dB dB dB % THD dB mVrms % THD dB % THD dB dB dB dB dB dB %THD dBV TACS =1, SATS = 1, Output = 1 Vpp at 6030 Hz f = 2520 Hz Relative to 6030 Hz f = 3500 Hz SATS = 1 f = 4120 Hz TACS = 1 f = 4980 Hz SATD = 15 (0 dB) f = 5900 Hz SATM = 1 f = 5960 Hz f = 6030 Hz f = 6090 Hz f = 7010 Hz f = 8060 Hz f = 9040 Hz f = 9290 Hz Conditions
TXSAT Noise Gain Stage SATDEV Nominal gain Gain adjustment range Gain adjustment size Distortion SATM switch mute attenuation DTMF Generator DTMF output level DTMF single tone distortion: TONEM switch on (via TBPO) TONEM switch off DTMF switch on (via RBPO) DTMF switch off DTMF high group pre-emphasis
SATS = 0, TACS = 1, SATM = 1 SATD[4:0] = 0 to 31 Output = 1.1 Vpp SATM = 0 VDD = 3.6 V, high & low tone Low group, TONEM = 1 TONEM = 0 High group, DTMFM = 1 DTMFM = 0 DTWIST = 0 DTWIST = 1 Output at MOD. TXSEN[3:0] = 0 to 15 Output = 1 Vrms BW = 30 Hz to 30 kHz
- 0.5 1.5
Gain Stage TXSENSE, SUMI to MOD pins Gain - 0.5 Gain adjustment - 2.8 Gain adjustment step size 0.2 Distortion Noise
10
ACE9040
ELECTRICAL CHARACTERISTICS
These characteristics are guaranteed over the following conditions unless otherwise stated (Note 1): TAMB = - 40 C to + 85 C, VDD = 3.6 V to 5.0 V Characteristic Min. Handsfree Rectifiers Attack time Decay time TX nominal output levels: d.c. offset a.c. level Value Typ. 1 35 0.3 1.4 0.5 1.6 Unit Max. ms ms V V Capacitors to GND = 68 nF at TXC & RXC pins VDD = 3.75 V Input at IPS = 0 mVrms Input at IPS = 40 mVrms, 1 kHz INPSENSE = 0 dB, HFS = 0 HFP = 1 VDD = 3.75 V Input at HFGIN = 0 mVrms Input at HFGIN = 100 mVrms, 1 kHz HFS =1, HFP = 1 VDD = 3.6 V, 3.3 F decoupling to GND at DEC pin MLI = 0, MIS = 1, VDD = 3.6 V MLI = 0, MIS = 1, PD = 0 MLI = 0, MIS = 0 VDD = 4.85 V VDD = 3.75 V Conditions
1.5
RX nominal output levels: d.c. offset a.c. level Voltage Outputs DEC & BIAS output voltage Source 1 mA Sink 1 mA Microphone disabled External Reference Resistor connected from pin RREF to GND Bandgap at BGAP LVN Supply Voltage Comparator VDD = 3.6 V VDD = 3.1 V LVN comparator operating lower limit of VDD Microphone Bias:
0.3 1
1.1
0.5 1.2
V V
1.70 2.7 2.7 - 0.1
(VDD-VSS)/2
1.9 2.9 2.9 0.10
V V V V k k V
100 68 1.10 1.35
- 10 2.00 1
10 20.0
A mA V
Default condition (high at VDD - 0.2 V) (low at 0.4 V)
11
ACE9040
ELECTRICAL CHARACTERISTICS
These characteristics are guaranteed over the following conditions unless otherwise stated (Note 1): TAMB = - 40 C to + 85 C, VDD = 3.6 V to 5.0 V Characteristic DC Characteristics Logic input high Logic input low Input Capacitance logic inputs leakage current AC Characteristics Clock input frequency: Serial interface & SC Filters Clock duty cycle Number of clock rising edges to input data Clock cycles between latch pulses on LEN Clock cycles before power-up and after powerdown Data setup time Data hold time Clock low Clock high Clock high to latch high Latch high to clock high Latch high Rise and fall times Power Supply Rejection Ratio: TX path (LI to TLPO) RX path (RXI to EPOP) Symbol Min. VIH VIL Cin IILK 0.7 x VDD - 0.3 Value Typ. Unit Max. VDD + 0.3 0.3 x VDD 10 1 V V pF A Conditions
SCLK, SD, LEN inputs VDD = 3.6 V & 0.0 V
fCLK D -100 40 24 30 8 tds tdh tcll tclh tcl tlc tlh PSRR 80 80 400 400 440 220 240
1.008 50 100 60
600 600
50
MHz ppm % clock cycles clock cycles clock cycles ns ns ns ns ns ns ns ns
Deviation from 1.008 MHz
VDD = 3.75 V 0.1 V. TA = - 40 C to + 85 C
- 12 - 20
dB dB
Crosstalk TX to RX (MOD to EPOP/EPON)
-45
dB
All digital inputs VDD = 3.8 V + 100 mVpp (a.c.) COMP[2:1] = 00. LI = 0 dB, V485 = 13.5 dB INPSENSE = 0 dB, softlimit on. AUDIODEV, RXSENSE = 0 dB THF, RHF, EARSENSE = 0 dB RXV, SIDETONE off. MOD = 0.2 VRMS
Data tds SCLK tcl tlc tclh tcll tdh
Latch tlh
Fig.3a Serial Interface Input Timing
12
ACE9040
TYPICAL FREQUENCY RESPONSES
TXBPF Relative Response vs Frequency
15
Pre-emphasis Relative Response vs Frequency
0
10 5
Relativ e Response (dB)
-10
Relativ e Response (dB)
-20
0 -5
-30
-10
-40
-15 -20
-50 10 100 1000 10000 100000 Frequency (Hz)
100
1000 Frequency (Hz)
10000
Figure 4
Figure 5
TXLPF Relative Response vs Frequency
10
RXBPF Relative Response vs Frequency
10
0
0
-10
Relativ e Response (dB)
-20
-30 -40
-50 -60 10 100 1000 10000 100000 Frequency (Hz)
Relativ e Response (dB)
-10
-20
-30 -40
-50 -60 10 100 1000 Frequency (Hz) 10000 100000
Figure 6
Figure 7
13
ACE9040
TYPICAL FREQUENCY RESPONSES
Transmit Overall Relative Response vs Frequency
10 5 0
Relativ e Response (dB)
0 10
SAT Filter Relative Response vs Frequency
-5
-10
-15 -20
-25 -30 -35 -40 10 100 1000 10000 100000 Frequency (Hz)
Relativ e Response (dB)
-10
-20 -30
-40
-50 1000 Frequency (Hz) 10000
Figure 8
Figure 9
14
ACE9040
DESCRIPTION
ACE9040 combines all the voice, data and signalling processing circuits for analog cellular telephones operating with the AMPS or TACS systems. Transmit channel functions comprise a microphone amplifier, soft limiter, bandpass speech filter, compressor, pre-emphasis filter, hard limiter, lowpass transmit filter and a gain control stage to set the deviation. Additional transmit circuits include a DTMF generator, a lowpass filter for either control data or signalling tone (ST), filters for supervisory audio tone (SAT), either transponded or locally re-generated, and deviation setting amplifiers for Data, ST and SAT. The outputs from the transmit functions feed a modulation combiner whose gain can be adjusted before driving a modulator and external power amplifier. ACE9040's receive path consists of a bandpass filter, expander, volume control and power amplifier to directly drive the earpiece, either differentially or in single ended modes. Sidetone and DTMF tones can be introduced into the receive path. Gain settings, filter characteristics and system control is programmed via a three wire serial interface to give optimum operation with either the AMPS or TACS analog cellular systems. To implement a handsfree function, both transmit and receive paths have rectifiers which enable signal amplitude monitoring via an external pin and signal path attenuators controlled via the serial interface. All filter characteristics are set by ratioed on-chip components and by a fixed externally input clock rate of 1*008 MHz and do not need trimming, filter response options are selected via the serial interface. Gain adjustments for different system specifications and component tolerancing are set via the serial interface using gain control blocks in the transmit and receive signal paths. These eliminate the need for any mechanically adjusted potentiometers. Some gain levels change automatically when the control bits for one of the standards are set, others are under user control. Power saving operates when an individual block is deselected and for the whole circuit when in Standby. The circuit combines high performance with minimum power consumption and uses as few external components as possible.
SERIAL CONTROL BUS
All functions are controlled via a three wire serial interface. Input is via pins SD for serial data, SCLK for the clock input and LEN for the control message latch signal. Incoming data bits are clocked in on the rising edges of SCLK clock input. At the end of each control message comprising three 8-bit data bytes, the rising edge of the LEN pulse latches in the data. A system controller should clock data out on clock falling edges to ensure the maximum timing margins. The SCLK clock input must be at 1*008 MHz and continuous whenever the ACE9040 is active because ACE9040's switched capacitor filters use clocks derived from SCLK to set frequency responses. ACE9040 expects a minimum of 30 clock cycles between LEN latch pulses, including the clock cycle containing the latch pulse. A minimum of 8 clock cycles before the beginning of an Operate command or after a Standby command are expected. Three data bytes DATA1, DATA2, and DATA3 contain bits for system selection, control and mute switches, gain control and filter response settings, as shown in figure 10. The last two bits of DATA3, DATA3[1] and [0], determine the message type, either "Operation", "Initializing mode 0", "Initializing mode 1" or "Handsfree". The details of these four modes are described in tables 2 to 19.
SCLK
SD
DATA1
DATA2
DATA3
EARLIEST START OF NEXT MESSAGE
765432107654321076543210
LEN
Fig. 10 Serial Receive Bus Timing
DATA3[1] 0 0 1 1
DATA3[0] 1 0 0 1
Mode "Operation" "Initializing mode 0" "Initializing mode 1" "Handsfree"
Table 1 Mode Selections
15
ACE9040
CONTROL BUS: OPERATION MODE
Data bit DATA3: [0] [1] [2] [5:3] [6] [7] DATA2: [0] [1] [2] [3] [4] [5] [7:6] DATA1: [0] [1] [5:2] [6] [7] Bit Name Function Effect when at 0 Must be "1" Must be "0" Operate See table 3 Off See table 5 Muted Muted Muted Muted See table 4 Disabled See table 6 Speech Speech See table 7 See table 4 Active Effect when at 1 Must be "1" Must be "0" Standby See table 3 On See table 5 On On On On See table 4 Enabled See table 6 DTMF DTMF See table 7 See table 4 Bypassed
DATA3[0] DATA3[1] PD RXV[2:0] HIZ EPH1 RXM SATM DATM TXM MLI DTMFEN DTMFMODE[1:0] DTMFM TONEM DTMF[3:0] MIS PREEMPH
Bus Mode Select Bus Mode Select Power Down Receive Volume Line Output Drive Enable Earpiece Mute Receiver Audio Mute Transmit SAT Mute Transmit Data Mute Transmit Audio Mute Microphone Select Enables each DTMF tone selection DTMF Tone Select Transmit DTMF Switch DTMF RX path Confirm Tone Switch DTMF Code Select Line Input Select Transmit Pre-emphasis Bypass
Table 2 "Operation Mode", DATA3[1:0] = 01.
RXV[2] 0 0 0 0 1 1 1 1 RXV[1] 0 0 1 1 0 0 1 1 RXV[0] 0 1 0 1 0 1 0 1 Gain in dB - 21 - 18 - 15 - 12 -9 -6 -3 0 MLI 0 0 1 1 MIS 0 1 0 1 Function LI selected, no gain MI selected, Micamp gain NOT ALLOWED LI selected, Micamp gain
Table 4 Microphone Input Select
Table 3 Receiver Volume Control Nominal Levels set by RXV[2:0].
EPH1 0 0 1 1 EPH0 0 1 0 1 Function Earphone mute External Earpiece (EPON to ground) Single ended output (EPON to EPOP) Differential output (EPON and EPOP)
Table 5 Earphone Mode Select (EHP0 in Initializing mode 0)
DTMFMODE[1:0] bits 1 and 0 0 and 0 0 and 1 1 and 0 1 and 1 Tone generated No tone. Low frequency only. High frequency only. Dual tones.
DTMF[3:0] bits Keypad 3210 legend 0000 1 0001 2 0010 3 0011 A 0100 4 0101 5 0110 6 0111 B 1000 7 1001 8 1010 9 1011 C 1100 * 1101 0 1110 # 1111 D
Low Freq. Hz. 697 697 697 697 770 770 770 770 852 852 852 852 941 941 941 941
High Freq. Hz. 1209 1336 1477 1633 1209 1336 1477 1633 1209 1336 1477 1633 1209 1336 1477 1633
Table 6 DTMF Mode Selection
Table 7 DTMF Tones
16
ACE9040
CONTROL BUS: INITIALIZING MODE 0
Data bit DATA3: [0] [1] [2] [3] [4] [6:5] [7] DATA2: [3:0] [7:4] DATA1: [0] [5:1] [6] [7] Bit Name Function Effect when at 0 Must be "0" Must be "0" See table 5 0 dB Active See table 9 See table 10 See table 10 See table 11 See table 11 See table 12 Off Off Effect when at 1 Must be "0" Must be "0" See table 5 2 dB Power Down See table 9 See table 10 See table 10 See table 11 See table 11 See table 12 On On
DATA3[0] DATA3[1] EPH0 DTWIST PDLVC COMP[2:1] INPS[0] INPS[4:1] RXSEN[3:0] RXSEN[4] SATD[4:0] SD SOFTLIMIT
Bus Mode Select Bus Mode Select Earpiece Mode Select DTMF Pre-emphasis Power Supply Comparator Compander Control Transmit Audio Gain Adjust Transmit Audio Gain Adjust Receive Audio Gain Adjust Receive Audio Gain Adjust SAT Modulation Gain Sidetone Enable Enables Softlimiter
Table 8 "Initializing Mode 0", DATA3[1:0] = 00.
INPS[4] INPS[3] INPS[2] INPS[1] INPS[0] 0 0 0 0 0 0 0 0 0 1 : : : : : : : : : : 1 1 1 1 0 1 1 1 1 1 Gain (dB) - 12*0 - 11*2 : : + 12*0 + 12*8
COMP[2] 0 1 1 0
COMP[1] 0 0 1 1
Mode Bypass Compander Internal Compander External Compander BAR Signal Input Mode (RBPO at high impedance)
Table 9 Compander Operating Modes set by COMP[2:1].
Table 10 INPSENSE Transmit Audio Nominal Gain settings by INPS[4:0].
RXSEN[4] 0 0 : : 1 1
RXSEN[3] 0 0 : : 1 1
RXSEN[2] 0 0 : : 1 1
RXSEN[1] 0 0 : : 1 1
RXSEN[0] 0 1 : : 0 1
Gain (dB) - 6*0 - 5*6 : : + 6*0 + 6*4
Table 11 RXSENSE Receive Audio Nominal Gain settings by RXSEN[4:0].
SATD[4] 0 0 : : 1 1
SATD[3] 0 0 : : 1 1
SATD[2] 0 0 : : 1 1
SATD[1] 0 0 : : 1 1
SATD[0] 0 1 : : 0 1
Gain (dB) - 4*5 - 4*2 : : + 4*5 + 4*8
Table 12 SATDEV Transmit SAT Nominal Modulation Gain settings by SATD[4:0].
17
ACE9040
CONTROL BUS: INITIALIZING MODE 1
Data bit DATA3: [0] [1] [3:2] [4] [6:5] [7] DATA2: [3:0] [7:4] DATA1: [3:0] [7:4]
Bit Name
Function
Effect when at 0 Must be "0" Must be "1" see table 14 RXSAT see table 15
Effect when at 1 Must be "0" Must be "1" see table 14 TXSAT see table 15 TACS see table 16 see table 16 see table 16 see table 16
DATA3[0] DATA3[1] TEST[1:0] SATS DATAF[1:0] TACS TXSEN[3:0] DATD[3:0] AUDEV[3:0] EARS[3:0]
Bus Mode Select Bus Mode Select Test Mode Select SAT source Select Data Filter Bandwidth Select Cellular System Select Combined Modulation Gain Data Modulation Gain Audio Modulation Gain Earpiece "EARSENSE" Gain
see table 16 see table 16 see table 16 see table 16
See table 19.
Table 13 "Initializing Mode 1", DATA3[1:0] = 10.
TEST[1] 0 1 0 1
TEST[0] 0 0 1 1
Test Mode Operate mode (not in test mode) Test DTMF Bypass TXLPF Bypass TXLPF & Softlimiter test
DATAF[1] 1 1
DATAF[0] 0 1
Cut-off Frequency 16 kHz 20 kHz
Table 14 Test Modes selected by TEST[1:0].
Table 15 Data Filter Bandwidths selected by DATAF[1:0].
TXSEN[3] DATD[3] AUDEV[3] EARS[3] 0 0 : : 1 1
TXSEN[2] DATD[2] AUDEV[2] EARS[2] 0 0 : : 1 1
TXSEN[1] DATD[1] AUDEV[1] EARS[1] 0 0 : : 1 1
TXSEN[0] DATD[0] AUDEV[0] EARS[0] 0 1 : : 0 1
Gain (dB) - 2*8 - 2*4 : : + 2*8 + 3*2
Table 16 TXSENSE, DATADEV, AUDIODEV, and EARSENSE Nominal Gains set, respectively, by TXSEN[3:0], DATD[3:0], AUDEV[3:0], and EARS[3:0].
18
ACE9040
CONTROL BUS: HANDSFREE MODE
Data bit DATA3: [0] [1] [4:2] [7:5] DATA2: [0] [1] [2] [4:3] [5] [6] [7] DATA1: [2:0] [5:3] [7:6]
Bit Name
Function
Effect when at 0 Must be "1" Must be "1" see table 18 see table 18 Off Transmit + 22 dB
Effect when at 1 Must be "1" Must be "1" see table 18 see table 18 On Receive + 32 dB AMPS must be "0" must be "0" -
DATA3[0] DATA3[1] THF[2:0] RHF[2:0] HFP HFS MIG not used AMPS not used not used not used
Bus Mode Select Bus Mode Select Transmit Handsfree Gain Receive Handsfree Gain Handsfree Rectifiers Power HF Output Connection Path Microphone Amplifier Gain Cellular System Select -
must be "0" must be "0" -
See table 19.
Table 17 "Handsfree Mode", DATA3[1:0] = 11.
THF[2] RHF[2] 0 0 0 0 1 1 1 1
THF[1] RHF[1] 0 0 1 1 0 0 1 1
THF[0] RHF[0] 0 1 0 1 0 1 0 1
Gain (dB) 0 -7 - 14 - 21 - 28 - 35 - 42 - 49
Table 18 TXHFGAIN and RXHFGAIN Handsfree Attenuator Nominal Gains, set by THF[2:0] and RHF[2:0].
19
ACE9040
CIRCUIT OPERATING MODES
ACE9040 has three operating modes: Operate, Standby and Sleep. In Operate mode all parts of the circuit are active, except for any explicitly powered down and the DTMF generator which only powers up when tones are generated. The pin STBY is pulled high in Operate mode to supply VDD to external audio circuits, such as a compander.
Power on Reset
At power up ACE9040 is put into Standby mode. ACE9040 is set up by the controlling processor via the serial interface using four control messages: "Operation", "Initializing mode 0", "Initializing mode 1" and "Handsfree". Usually the "Operation" control message would be sent last as it contains the power down/up bit PD.
Standby Mode
Standby mode is used when the cellular terminal is waiting for a call and is selected by an "Operation mode" control message with bit PD at "1". In this mode all analog circuits, data paths, filters and their clock drivers are powered down giving a greatly reduced supply current. In standby mode all switch and level controls retain their previous state, the pin STBY is not driven removing the VDD supply from external circuits. To leave Standby mode an operate command should be given by using an "Operation mode" control message with bit PD at "0".
CELLULAR SYSTEM SELECTION
Two control bits are used to set the filter responses and gain levels for the AMPS or TACS cellular systems. These bits are TACS in control message "Initializing mode 1" and AMPS in control message "Handsfree mode" and select the system as shown in table 19. Bits AMPS 0 0 1 1 TACS 0 1 0 1 System Selected Not valid TACS AMPS Not valid
Sleep Mode
Sleep mode is the same as Standby but without a clock input. To enter sleep mode the standby command should be given and after a delay of at least 20 s the SCLK clock stopped. To wake-up from sleep mode, the the SCLK clock must be started and after a delay of at least 100 s an operate command given.
Table 19 Cellular System Selection
TRANSMIT VOICE PATH
10nF SLO IPS
SOFTLIMIT NOM 8dB -4 to +20.8dB INPS[4:0] DTMFM 0 to -49dB THF[2:0]
HANDSFREE RECTIFIER HFS 0dB TXBF DTMF INSPENSE HFGAIN SIDETONE TO RECEIVE VOICE PATH RXC
TXC 68nF HF TBPO
LI 22/32 dB MIG MLI MI MIC.AMP
0 to -30dB MIS SOFT LIMIT
10nF
92% LEVEL DETECT
TEST[1:0]
CIN CRCOUT 3 and 97% LEVELS DETECT COMPRESSOR 2dB : 1dB TEST[1:0] COMP[2:1] VMIDTX CRCIN 100nF VMIDTX 82nF COUT PREIN 0dB @ 1kHz +6dB/octave PREEMPAHSIS PREEMPH +15.4dB @ 3.75V +16dB @ 4.85V HARD LIMIT TEST[0] -8dB TXLPF AUDIODEV -2.8 to + 3.2dB AUDEV[3:0] TXM TLPO VMIDTX TLPO DRIVER 33nF
-7dB TACS -11dB AMPS Compressor bypass 0dB AMPS/TACS GAIN CONTROL COMP[2:1]
Fig. 11 Transmit Voice Path
20
ACE9040
TRANSMIT INPUT SIGNAL PRECONDITIONING Microphone Amplifier (MIG)
Microphone signals input at MI via switch MLI are amplified by a gain selectable amplifier of either 22 dB or 32 dB, controlled by the MIG bit in the "Handsfree mode" control message. The microphone amplifier's input can also be connected to the line input LI via the MLI switch. The microphone amplifier's output drives the soft limiter via switch MIS which also allows higher level signals from the line input LI to bypass the microphone amplifier to drive the soft limiter directly. These two switches are controlled by the MIS and MIL bits in the "Operation mode" control message.
HANDSFREE FUNCTIONAL BLOCKS
Between the transmit bandpass filter and the compressor two extra functions are included for use with handsfree operation. Firstly an attenuator HFGAIN is provided to give progressive signal reduction in handsfree mode with a range of 0 to - 49 dB in 7 dB steps, set by bits THF[2:0] in the "Handsfree mode" control message. The HFGAIN attenuator's output drives pin TBPO which is externally capacitively coupled to the compressor input at pin CIN and internally drives both the soft limiter and sidetone circuits. The second function provided for handsfree operation is a signal rectifier whose output, filtered by an external capacitor at pin TXC, drives output pin HF via switch HFS with a d.c. transmit level. Switch HFS is controlled by bit HFS in the "Handsfree mode" control message. Under control of bit HFS both receive and transmit levels are available at HF output pin for external comparison to implement the handsfree function. The handsfree system is further described in the section HANDSFREE OPERATION.
Soft Limiter
Signal amplitude is restricted without clipping to the correct level for maximum F.M. deviation by the soft limiter. This operates as an AGC system, controlled by the signal amplitude at the compressor input and the hard limiter output later in the signal processing path. If the signal is too large at either of these points the soft limiter forward gain is reduced. The nominal soft limiter gain range of 0 to - 30 dB in 64 steps of 0*5 dB covers all normal volume changes occuring during a conversation. Soft limiter attack and decay times are set by internal clocks derived from SCLK and ramp the gain steps at nominal rates of one step down every 40 s when the signal is too large and one step up every 1*68 ms when the signal is too small. The soft limiter output at pin SLO is externally coupled with a capacitor to the input pin IPS of the following gain adjust stage, INPSENSE. When the speech channel is used to send DTMF signalling tones a switch, controlled by bit DTMFM in the "Operation mode" control message, selects the internal DTMF signal rather than the speech signal at input IPS. For test purposes TEST[1:0] bits in the "Initializing Mode 1" control message can configure switches to give access to the softlimiter comparator inputs. When TEST[1:0] bits are high the 3 & 97 % window comparator is switched from the hard limiter output to PREIN input and the 92 % comparator is switched to IPS input.
COMPRESSOR
ACE9040 provides a 2:1 compressor to halve the transmit dynamic range as required by analog cellular systems. Within the operating signal range each 2 dB change in input level gives a 1 dB change in output level. A transmit signal is input through pin CIN and output on pin COUT, the signal is referenced to a mid-supply voltage. CRCIN and CRCOUT are connections for the external attack and delay time constant setting components. The compressor's nominal unity gain level is 707 mV. Above this level the signal at CIN is attenuated and below this level the signal is amplified to achieve the 2:1 dB compression. Table 20 gives the nominal, Vmax and Vmin levels at CIN and nominal levels at COUT corresponding with the TACS and AMPS systems for 0 dB, maximum and minimum deviation. The gain of the INPSENSE amplifier should be set so that the compressor operates within these signal levels for a given input signal at the MIC or LI input. For the usual attack time of 3*0 ms and decay time of 13*5 ms a 180 k resistor is connected between CRCIN and CRCOUT pins and a 100 nF capacitor between CRCIN and GND pins. An 82 nF capacitor should be connected between the VMIDTX and GND pins. Attack and decay time is measured with a 12 dB step, - 8 dB to - 20 dB relative to the unaffected level. Attack and decay times are respectively defined at points on the output envelope where it reaches x 1*5 and x 0*75 of the final steady state level. External compressor connections allow the use of external coupling capacitors to remove d.c. offsets and optionally an external compander. The compressor can be internally bypassed allowing use of ACE9040 without companding in non-cellular applications, or for test purposes. Bits COMP[2:1] in the "Initializing mode 0" control message control the operation of the internal compander and are used to switch both the transmit compressor and receive expander into or out of the signal path. When not in use the internal compressor and expander are both powered down. Nominal Input at CIN (0dB) levels mVrms 56 71 Nominal Output at COUT levels mVrms 200 225
INPSENSE AMPLIFIER and TXBPF FILTER
Both microphone and transmit voice path tolerances are trimmed in the INPSENSE gain adjustment block following the soft limiter and DTMF switch. INPSENSE has a nominal gain of 8*0 dB with a trim range of - 12*0 to + 12*4 dB relative to the nominal gain set by bits INPS[4:0] in the "Initializing mode" control message. Transmit signal preconditioning is completed by a bandpass filter TXBPF to limit the audio signal to a speech bandwidth of 300 Hz to 3*4 kHz. This filter uses switched capacitor techniques and is preceded by an anti-alias filter and followed by a smoothing filter to remove the clock from its output. The typical frequency response is shown in figure 4 which also shows the mask defined by type approval limits.
System TACS AMPS
Vmax at CIN Vrms dB 1.0 + 25 1.0 + 23
Vmin at CIN mVrms dB 1.77 - 30 2.25 - 30
Table 20 Compressor CIN and COUT signal levels for TACS and AMPS
21
ACE9040
FINAL MODULATION PREPARATION Pre-emphasis
A pre-emphasis filter follows the compressor to boost the amplitude of higher audio frequencies by tilting the frequency response by 6 dB per octave across the whole speech band as shown in figures 5 and 8. To prevent overload in the pre-emphasis filter the signal first passes through an attenuator set to suit the system in use. If an external compander is used or the companding function is bypassed the gain is set to 0 dB. When using the internal compander the gain is set to - 7 dB for TACS or - 11*0 dB for AMPS. Compander bypass is determined by control bits COMP[2:1]. The pre-emphasis filter and attenuator input is pin PREIN and the output is an internal connection to the hard limiter. The preemphasis filter, but not the attenuator, can be bypassed if the PREEMPH bit in the "Operation mode" control message is set to "1". "V485". For the nominal supply voltages of 4.85 V and 3.75 V gain is respectively 16 dB (V485 pin at "1") and 13.5 dB (V485 pin at "0"). An 8 dB attenuator follows the limiter to prevent any further clipping of the signal in the following transmit lowpass filter.
TX Lowpass Filter TXLPF
A TXLPF lowpass filter with an optimised stop band response limits the signal bandwidth to a cut-off frequency of 3*0 kHz, the frequency response is shown in figure 6. The combined frequency response of the pre-emphasis and lowpass filter stages is shown in figure 8. It is possible for test purposes to bypass this lowpass filter by setting bit TEST[0] in the "Initializing mode 1" control message to a "1".
Hard Limiter
To ensure compliance with the peak deviation specification for cellular telephone systems, a hard limiter follows the pre-emphasis filter to remove any transient level changes that have passed through the soft limiter. This limiter will handle large signals and has symmetrical clipping levels close to the supply rails VDD & VSS (GND). To ensure clipping at the same hard limiter input signal level with both the nominal power supply voltages, hard limiter gain is adjusted by an external pin
Speech Deviation Level Setting
A controlled gain stage AUDIODEV sets the output level to give the required FM deviation for speech. The gain is set by bits AUDEV[3:0] in the "Initializing mode 1" control message. AUDIODEV is followed by a transmit audio mute switch enabled by bit TXM in the "Operation mode" control message. A buffer drives output pin TLPO with the transmit speech signal (and DTMF when in use) which is added with DATA/ST and SAT tones in the modulation combiner.
TRANSMIT DATA AND DTMF PATHS
16/20kHz DATAF[1:0] DATI LOW-PASS FILTER DATM
-2.8 to + 3.2dB DATD[3:0] DATO DATADEV
VMID IPS DTMFM
DTMF[3:0] DTMF
DTWIST DTMFMODE[2:1] PREEMPHASIS MODE
TRANSMIT VOICE PATH RECEIVE VOICE PATH
TONEM
RXI DTMF
Fig. 12 Transmit Data and DTMF Paths
Transmit Data
Data communication from mobile terminals to base stations in the AMPS and TACS cellular phone systems takes place over the Reverse Control Channel (RECC) during call set-up and in short bursts over the Reverse Voice Channel (RVC) during a call. RECC or RVC data is transmitted for AMPS or TACS as a 10 kHz or 8 kHz Manchester Coded FSK signal respectively. The data signal is generated by the ACE9050 "System Controller and Data Modem" or similar digital circuit to drive ACE9040's DATI input pin. The DATI input data signal is filtered using a 4th order Butterworth lowpass filter with nominal - 3 dB points of 16 kHz for TACS, or 20 kHz for AMPS. This filter is implemented using switched capacitor techniques and is preceded by a continuous time anti-alias
22
ACE9040
filter, the output buffer includes a clock rejection filter. The cutoff frequencies are programmed by bits DATAF[1:0] in the "Initializing mode 1" control message. Filtered data passes through the mute switch DATM and a variable gain stage DATADEV with a range of - 2*8 to + 3*2 dB to set the required level of deviation. The mute switch is controlled by bit DATM in the "Operation mode" control message. DATADEV is controlled by bits DATD[3:0] in the "Initialising Mode 1" control message. The data signal is buffered out to pin DATO to drive the modulation combiner. operation. To change DTMF tones, an "Operation mode" control message with DTMFEN set to "0" must be sent to cancel the previous selection as the DTMF tone can only be changed when DTMFEN=0. This prevents any spurious tones being generated. An optional pre-emphasis of 2 dB of the high frequency tone group above the level of the low frequency group is enabled by bit DTWIST in the "Initializing mode 0" control message. DTMF tones can be selected to replace the speech in either or both the transmit and receive paths. In the transmit path setting bit DTMFM to "1" as in the "Operation mode" control message will connect the DTMF signal to INPSENSE gain adjustment block's input in place of the speech signal. In the receive path setting bit TONEM to "1" in the "Operation mode" control message will connect the DTMF signal to the input to RXSENSE gain adjustment block in place of the speech input at pin RXI. In each case the DTMFEN bit must also be "1". DTMF signals are generated as sinewaves by an internal digital to analog converter and are smoothed by the transmit and receive filters. DTMF waveforms start and stop at a zero crossing to avoid transients in the filters and to limit their bandwidth. The DTMF signal is brought out directly on pin DTMF without further buffering. The DTMF generator is powered down whenever a tone is not being generated, by setting DTMFMODE[1:0] to "00".
DTMF
DTMF tones are generated when commanded via the serial interface and conform to the standard CCITT frequencies. All 16 standard tone pairs or any individual tone can be generated. To select DTMF tones data bits for transmission DTMFEN, DTMFMODE[1:0] and DTMF[3:0] need to be set using an "Operation mode" control message. Data bits DTMFMODE[1:0] select low, high or both tones of the pair as shown in table 6. Bits DTMF[3:0] select the tone pair as shown in table 7. DTMFEN set to "1" enables DTMF
TRANSMIT & RECEIVE SAT PATHS
RSO 10dB RSI RXSAT 6kHz FILTER SCHMITT -4.5 to +4.8dB SATD[4:0]
SATS -12dB TSI TXSAT 6kHz FILTER -15dB
SATM TSO
SATDEV
VMID
Fig. 13 Transmit and Receive SAT Paths.
Re-transmitted SAT
ACE9040 provides two alternative paths for Supervisory Audio Tones (SAT). The first of these re-transmits the received SAT tone to the base station after narrow band filtering and providing signal level adjustment. This path is selected by setting SATS bit to "0" in the "Initializing mode 1" control message. The baseband signal from the receiver FM discriminator drives the ACE9040 through the RSI pin into the RXSAT 6 kHz bandpass filter required for AMPS or TACS. The recovered SAT signal then passes through a 10 dB amplifier and the SATS selector switch to the deviation setting amplifier SATDEV. This is controlled by bits SATD[4:0] in the "Initializing mode 0" control message. SAT then passes through the SATM mute switch, controlled by bit SATM in the "Operation mode" control message, to output pin TSO for input to the modulation combiner.
Regenerated SAT
The alternative SAT path externally measures the SAT frequency and generates a local tone to match. This route is
23
ACE9040
selected by setting the SATS bit to "1" in the "Initializing mode 1" control message. The ACE9040 connects the receive filter RXSAT output through a Schmitt trigger to drive pin RSO with a logic level version of the received SAT. A system controller, such as an ACE9050, detects the frequency and generates a digital signal to drive back into the ACE9040 on pin TSI. After the signal level is reduced by -12 dB a 6 kHz bandpass filter TXSAT converts this square-wave into a sinewave. This is followed by a - 15 dB attenuator to reduce the near logic level signal to a normal modulation level. This signal drives the same SATDEV deviation setting stage and mute switch SATM as the returned signal to give an output at TSO.
Base Station Originated SAT
ACE9050, System Controller, can be used to generate a squarewave SAT at 6 kHz which is input to pin TSI and filtered by the TXSAT filter and output at TSO. The RXSAT filter path with its output at RSO, can be used to filter the received SAT from a mobile for verification by an external frequency detector that the mobile is transponding the correct tone. This is the same as the regeneration loop above but starting with generation.
TRANSMIT SIGNAL COMBINER
TLPO
AUDIO
AUDIODEV
TSO
SAT SATDEV DATA DATADEV
DATO SUMO
30dB SUMI + VMID
-2.8 to +3.2dB TXSEN[3:0] MOD TXSENSE
Fig. 14 Transmit Signal Combining Network and Modulation Driver
Used to modulate the transmitted r.f. output, the speech and optional DTMF signals at TLPO, SAT at TSO, and data and ST at DATO, are combined using an internal op-amp. This op-amp has an inverting input at pin SUMI and output at pin SUMO, the non-inverting input is internally biased to VMID. With an external feedback resistor between SUMI and SUMO, external resistors sum the inputs into pin SUMI and are chosen for each different cellular system to select the relative and absolute gains to give the correct deviation for each component of the modulation. Individual fine adjustments to take out component value tolerances can be made by setting: AUDIODEV, SATDEV and DATADEV gains, described in more detail in the sections TRANSMIT VOICE PATH, TRANSMIT AND RECEIVE SAT PATHS, and TRANSMIT DATA AND DTMF PATHS. A fine adjustment is made to the combined signal level by TXSENSE which drives the modulator through pin MOD. The gain of TXSENSE is set by bits TXSEN[3:0] in the "Initializing mode 1" control message over the range - 2*8 to + 3*2 dB.
24
ACE9040
RECEIVE VOICE PATH
100nF 33nF RBPO 8dB -6.4 to 6.4dB 180k RXI TONEM 10nF RXSENSE DTMF INPUT HFGIN +5dB SIDETONE INPUT (-19dB) HIZ LODRIVE NOM -12dB -21 to 0dB 0 to-49dB -2.8 to + 3.2 EPH0/EHP1 VMID + 6dB EARSENSE RXLEVEL HFATTEN TXC HANDSFREEE RECTIFIER _ + 6dB EAMP HFS EARPIECE DRIVER EPON 64W 3.3F + EPH0/EPH1 EPOP 150W LO RXBPF RXM EXPGAIN 180k ERCIN 82nF
EIN ERCOUT
0dB
12.3dB EXPANDER 1dB to 2dB
VMIDRX EOUT
COMP[2:1] 10nF
RXC 68nF
HF
EAMPI
EAMPFB
EAMPO
Fig. 15 Receive Voice Path
De-emphasis and Receive Signal Input
Demodulated FM signals drive the RXI input pin via an external de-emphasis lowpass R-C filter of typically 180 k and 10 nF. With TONEM switch set to RXI the input signal is amplified in the block RXSENSE with a gain of + 8 dB. RXSENSE also provides fine adjustment over a range of - 6*0 dB to + 6*4 dB to take up signal level tolerances in the receiver output. Fine gain adjustment is controlled by RXSEN[4:0] bits in the "Initializing mode 0" control message. When the DTMF generator in the transmit section is in use its output can be switched into the receive path to replace the RXI signal by setting bit TONEM in the "Operation mode" control message to "1". This does not affect the transmitted signal but allows the user to hear DTMF tones to confirm key press operation. ACE9040's companion device "ACE9030: Radio Interface and Twin Synthesiser" are bandlimited by its output filter and ACE9040's internal DTMF tones are generated as sinewaves without the need for a further anti-aliasing filiter. RXBPF filter output passes through the receive mute switch controlled by bit RXM in the "Operation mode" control message and is buffered to drive pin RBPO by amplifier EXPGAIN. During mute the RBPO pin is driven to the signal ground voltage at mid supply (as found on pin BIAS). EXPGAIN gain is nominally 12.3 dB when using the internal expander and 0 dB when using an external expander. The output circuit driving RBPO includes a smoothing filter to remove clock noise.
Expander RX Bandpass Filter
The RXSENSE amplifier's output is bandpass filtered to the speech bandwidth of 300 to 3400 Hz by receive bandpass filter RXBPF, as shown in figure 7. RXBPF uses switched capacitor filter techniques but does not include an anti-alias input filter as signals at RXI from the external receiver's output and the internal DTMF generator's output are already bandlimited. The F.M. discriminator output signals from Input to the expander at pin EIN is coupled by an external capacitor from RBPO to remove any d.c. voltage offsets. Using external coupling also allows the option of using an external compander or bypassing the expander if a linear system is required. In either case the signal should feed back into ACE9040 at pin HFGIN. ACE9040's compander can be bypassed by setting bits COMP[2:1] in the "Initializing mode 0" control message to "00". A ring tone from the BAR (Beep, Alarm, Ring) generator of ACE9050 "System Controller" can be added to the
25
ACE9040
expander input EIN by using an external summing network and internally open circuiting the drive to pin RBPO during the tone (not just muting the speech). This is achieved with bits COMP[2:1] in the "Initializing mode 0" control message set to "01". Signal dynamic range at input pin EIN is doubled in the 1:2 expander to restore the original signal. Within the operating signal range each 1 dB change in input level gives a 2 dB change in output level. The expander output drives pin EOUT which is coupled by an external capacitor to the input pin HFGIN. The external connection allows use of an external compander and removes any d.c. voltage offsets. Bits COMP[2:1] in the "Initializing mode 0" control message can be used to select external companding mode and power down the internal compressor and expander. The expander's unity gain level EIN to EOUT is 1V. Above this level gain is applied to the signal at EIN and below this level the signal is attenuated to achieve 1:2 dB expansion. Table 21 gives nominal, Vmax and Vmin levels at EIN and nominal levels at EOUT corresponding with the TACS and AMPS systems for 0 dB, maximum and minimum deviation. The gain of the RXSENSE amplifier should be set so that the expander operates within these signal levels for a given demodulated signal range at the RXI input. Expander pins ERCIN and ERCOUT are used to set the attack and decay times for the expansion process. For the usual attack time of 3.0 ms and decay time of 13.5 ms, a resistor of 180 k is connected between ERCIN and ERCOUT pins and a capacitor of 100 nF from ERCIN to GND. An 82 nF capacitor should be connected between VMIDRX and GND. Attack and decay time is measured with a 6 dB step, - 4 dB to - 10 dB relative to the unaffected level. Attack and decay times are defined respectively at points on the output envelope where it reaches x 0.57 and x 1.5 of the final steady state level. 2*8 to + 3*2 dB. A sidetone signal from the output of the handsfree attenuator HFGAIN at pin TBPO is added at EARSENSE's input if bit SD in the "Initializing mode 0" control message is set to "1". The output of this block is at pin EAMPI. The signal at pin EAMPI is amplified by an opamp whose gain is set by external resistors, allowing overall gain setting for different models of cellular terminal. A resistor is connected from EAMPI to the amplifier input pin EAMPFB and a feedback resistor is connected from the amplifier output EAMPO to EAMPFB. The ratio of these two resistors sets the gain and the opamp's output including feedback resistors should not be loaded with less than 15 k. Additional filtering can also be added to the receive path using the EAMP opamp.
Earpiece
The earpiece drivers have outputs at pins EPOP and EPON. One of three modes of output drive or a muted output condition is selected by bits EPH1 and EPH0, see table 5. A dynamic earpiece, typically of 150 resistance in series with 800 H, can be driven when connected between pin EPON and EPOP. The drive mode can be either differential (EPH1 = 1, EPH0 = 1) or single ended (EPH1 = 1, EPH0 = 0). The differential output, drives a minimum of 4 Vpp into the load. The single ended output appears at EPON and drives a minimum of 2 Vpp into a load referenced to pin EPOP, which provides an output voltage at mid-supply. Output drive is setup for an external handsfree earpiece with EPH1 = 0 and EPH0 = 1. This load, typically of 64 resistance in series with 3.3 F, is driven from pin EPON to ground and the EPOP output is put into a high impedance state. The minimum drive into this load is 1.1 Vpp. The input for the EPOP and EPON output drivers is driven by the signal at the EAMPO pin for single ended and differential outputs or from EAMPI directly for a handsfree earpiece, bypassing the EAMP opamp. The gain from the earpiece drivers' common input, to both EPON's inverting and and EPOP's non-inverting outputs, is nominally + 6 dB.
Volume Control and Handsfree Attenuator
Two variable gain stages follow the expander, RXLEVEL for the volume control and HFATTEN for use with handsfree mode. Both blocks provide attenuation, expressed as gain to assist system level design, RXLEVEL from 0 to - 21 dB and HFATTEN from 0 to - 49 dB. RXLEVEL is controlled by bits RXV[2:0] in the "Operation mode" control message and HFATTEN is controlled by bits RHF[2:0] in the "Handsfree mode" control message.
Line Output
Line output amplifier LODRIVE with its output at pin LO has a gain of + 5 dB and is used to drive an external audio power amplifier. LODRIVE can drive a 1 k load with a minimum of 1 Vrms. The LO output can be put into a high impedance state by setting bit HIZ in the "Operation mode" control message to "0". During power down EPON and EPOP and LO are tied to mid-supply voltage.
RX Audio Output: Line Output and Earpiece
Following the handfree attenuator the signal path splits into two parallel paths: a line output for loudspeaking phones and drivers for a dynamic earpiece or external handsfree earpiece. Bits EPH1 and EPH0 in the "Operation Mode" and "Initializing Mode 0" control messages respectively control the operation of these outputs, see table 5. The earpiece output path begins with a variable gain stage EARSENSE which is controlled by bits EARS[3:0] in the "Initializing mode 1" control message to give a gain range of -
HANDSFREE OPERATION
In a handsfree telephone the simplest method of preventing `howl round' caused by acoustic feedback is to attenuate either the forward or return path until the loop gain is too low for sustained oscillation. The least active path is attenuated so the signal level in each path must be detected and compared so that the quieter can be attenuated. In the ACE9040 the signal level in both the transmit and the receive paths are rectified, with smoothing capacitors at Nominal Input at EIN (0dB) levels mVrms 245 245 Nominal Output at EOUT levels mVrms 60 60
System TACS AMPS
Vmax at EIN Vrms dB 1.0 + 12.5 1.0 + 12.3
Vmin at EIN mVrms dB 43 - 15 22 -21
Table 21 Expander EIN and EOUT signal levels for TACS and AMPS
26
ACE9040
pins TXC and RXC respectively, to give d.c. voltages corresponding to the signal levels. A switch HFS with its output at pin HF can be internally toggled between TXC and RXC to allow measurement of the two levels at these pins by an external level sensing circuit such as an analog to digital converter input of ACE9030. The HFS switch is controlled by bit HFS in the "Handsfree mode" control message. The system controller after comparison of the voltage levels at TXC and RXC pins can attenuate the weaker signal path by up to 49 dB, in 7 dB steps using blocks HFGAIN for transmit and HFATTEN for receive. Bits THF[2:0] and RHF[2:0] in the "Handsfree mode" control message are used to set the gains of HFGAIN and HFATTEN respectively. The rate of change of gain should be limited in the system controller to allow normal conversation. Attack and decay time constants are set by the resistance and capacitance on the TXC and RXC pins. With the internal resistor to ground of approximately 500 k and an external capacitor to ground of 68 nF the normal attack time of 1 ms and decay time of 35 ms is achieved. By adding a parallel resistor the ratio of attack to decay time can be altered. To save power in a hand portable when handsfree operation is not needed, the transmit and receive signal rectifiers can be switched off by setting bit HFP in the "Handsfree mode" control message to "0".
OP-AMP Reference Current
Reference currents for all the internal op-amps are set by an external resistor connected from pin RREF to ground (VSS). Nominal values are 100 k for VDD = 4*85 V and 68 k for VDD = 3*75 V. A stable discrete resistor should be used to ensure consistent operation over a wide temperature range.
Power Supply Comparator - Reset Output
A power supply comparator is provided to give a reset at power-on and enable the system controller to initiate a clean shut-down sequence if the battery voltage falls too low. When VDD is below a band-gap derived threshold the open-drain outut pin LVN drives to a logic low. This occurs for VDD exceeding 1 V but less than a typical threshold of 3*35 V. An external resistor at LVN provides a pull-up to VDD with a capacitor to ground (VSS) to give a power-on reset delay. Typical values for RC are 220 k and 150 nF. This RC combination also removes short transients or noise pulses from the signal at LVN during power up. If this comparator is not required the bandgap and comparator can be powered down by setting bit PDLVC in the "Initializing mode 0" control message to a "1".
Serial Data Clock
All switched capacitor filter switching clocks are derived from the serial data clock SCLK which must be fixed at 1*008 MHz to ensure correct frequency responses.
BIASES AND REFERENCES
DEC 3.3F BIAS RREF 100k/ 68k* MICBIAS BGAP 10nF *VDD = 3.75V
2 5 64 44
AMPLIFIER
BIAS GENERATOR
VMIDRX
6
An uncommitted op-amp is provided with its non-inverting input internally connected to VMID, inverting input at pin AMPI and output at pin AMPO.
VMIDTX
Fig. 16 Bias Circuits
BIAS, VMID and MICBIAS
Within ACE9040 most signals are single ended and swing either side of a mid-supply reference voltage. These internal references are all labelled VMIDxx in this data sheet. A low impedance voltage source at mid-supply for use as an external signal ground is available on pin BIAS. This is a buffered copy of the voltage at pin DEC which is from an internal high impedance potential divider between VDD and VSS. The DEC pin should be decoupled to ground with a capacitor of greater than 3.3 F. Two additional buffers provide copies of DEC's voltage at pins VMIDTX and VMIDRX, these are used as internal signal grounds for the transmit and receive paths respectively. VMIDTX and VMIDRX pins should be decoupled to GND with 82 nF capacitors. By using separate mid-supply signal grounds crosstalk due to the compander time constant circuits and the speech and tone signals are kept to a minimum. Pin MICBIAS gives the bias needed for an electret microphone nominally 0*8 times VDD, e.g. when VDD is 3*75 V MICBIAS = 3 V
27
ACE9040
APPLICATIONS INFORMATION
To help with system set up tables 22 to 25 show ACE9040's functions and their respective controlling bits. Table 23 shows the gains and filter characteristics predetermined when setting the TACS & AMPS cellular system selection bits. Tables 23 & 24 show these functions respectively for the transmit and receive sections of ACE9040. Table 25 shows the four control messages with an example of the data to turn all ACE9040 functions on.
Function Controlled by TACS & AMPS Bits Internal pre-emphasis gain control. TACS = - 7.0 dB AMPS= - 11.0 dB TACS 1 0 AMPS 0 1
Table 22 Functions Controlled by TACS & AMPS Bits
Gain and filter set-ups for TACS, AMPS and user control bits: Transmit TACS Microphone amp Soft limiter INPSENSE gain adjust TXBPF TX bandpass filter HFGAIN, TX Handsfree attenuator Compressor: Compression about unaffected level. (707 mVrms, - 3 dBV) Pre-emphasis gain control (Internal compressor) Pre-emphasis gain control HARD LIMIT, Hard deviation limiter TXLPF TX low pass filter AUDIODEV, TXSENSE, signal Nominal TX Channel Gain (bypassed compressor) 22 or 32 dB 0 to - 30 dB + 8 dB (- 12.8 to + 12 dB) 0 dB 0 to - 49 dB 2:11 - 7 dB 0 dB + 16.5 dB @ 4.85V + 13.5 dB @ 3.75V - 8 dB 0 dB (-2.8 to + 3.2 dB) 0 dB (-2.8 to +3.2 dB) 28.52 dB @ 3.75 V 31.52 dB @ 4.85 V AMPS 22 or 32 dB 0 to - 30 dB + 8 dB (- 12.8 to + 12 dB) 0 dB 0 to - 49 dB 2:11 - 11 dB 0 dB + 13.5 dB @ 3.75V + 16.5 dB @ 4.85V - 8 dB 0 dB (-2.8 to + 3.2 dB) 0 dB (-2.8 to +3.2 dB) 23.52 dB @ 3.75 V 26.52 dB @ 4.85 V User control bit(s) MIG Internal INPS[4:0] Fixed THF[2:0] Fixed TACS & AMPS Fixed V485 pin Fixed AUDEV[3:0] TXSEN[3:0]
Notes: 1. Above the unaffected (0 dB gain) level the compressor attenuates and below this level it provides gain. 2. MIC gain = 22 dB
Table 23 Transmit gain and filter set-ups for TACS, AMPS and user control bits
28
ACE9040
Gain and filter set-ups for user control bits: Receive
TACS External De-emphasis RXSENSE: Receive audio gain RXSENSE: Receive audio gain adjustment range RXBPF: RX bandpass filter RX Expander gain EXPGAIN: Internal RX Expander gain EXPGAIN: External Expander: Expansion about unaffected level (1000 mV, 0 dBV) RXLEVEL, Receive volume control HFATTEN, RX handsfree attenuator EARSENSE Ear piece driver Nominal Receive Gain (Expander bypassed) DATA and SAT Filters TX data path filter cut-off TX & RX bandpass SAT filter centre frequency 16 kHz 6 kHz 20 kHz 6 kHz DATAF[1:0] Fixed - 21 dB1 + 8 dB - 6 to + 6.4 dB 0 dB + 12.3 dB 0 dB 1:22 - 12 dB (+ 12 to - 9 dB) 0 to - 49 dB 0 dB (- 2.8 to + 3.2 dB) 6 dB - 6.7 dB AMPS - 21 dB1 + 8 dB - 6 to + 6.4 dB 0 dB + 12.3 dB 0 dB 1:22 - 12 dB (+ 12 to - 9 dB) 0 to - 49 dB 0 dB (- 2.8 to + 3.2 dB) 6 dB - 6.7 dB User control bit(s) Fixed externally Fixed RXSEN[4:0] Fixed Fixed Fixed Fixed RXV[2:0] RHF[2:0] EARS[3:0] Fixed Fixed
Notes: 1. Attenuation with an external de-emphasis network of series 180 k with 10 nF to GND at RXI input. 2. Above the unaffected (0 dB gain) level the expander provides gain and below this level it attenuates .
Table 24 Receive, Data and SAT gain and filter set-ups for user control bits
29
ACE9040
OPERATING MODE D5 D4 D3 DTMF3 DTMF2 DTMF1 DTMFEN MLI TXM RXV2 RXV1 RXV0 START-UP BIT SETTINGS 0 0 0 00HEX 0 0 1 0FHEX 1 1 1 F9HEX
WORD/BIT
D7
PREEMPH
DTMFMODE1
DATA 1 DATA 2 DATA 3 DATA 1 DATA 2 DATA 3
D6 MIS
DTMFMODE0
EPH1 0 0 1
HIZ 0 0 1
D2 DTMF0 DATM PD 0 1 0
D1 TONEM SATM 0 0 1 0
D0 DTMFM RXM 1 0 1 1
WORD/BIT
D7 DATA 1 SOFTLIMIT DATA 2 RXSEN3 DATA 3 INPS0 DATA 1 DATA 2 DATA 3 1 0 0
D6 SD RXSEN2 COMP2 0 0 1
INITIALIZING MODE 0 D5 D4 D3 SATD4 SATD3 SATD2 RXSEN1 RXSEN0 INPS4 COMP1 PDLVC DTWIST START-UP BIT SETTINGS 1 0 0 A1HEX 0 0 1 08HEX 0 0 1 4CHEX
D2 SATD1 INPS3 EPH0 0 0 1
D1 SATD0 INPS2 0 0 0 0
D0 RXSEN4 INPS1 0 1 0 0
WORD/BIT
DATA 1 DATA 2 DATA 3 DATA 1 DATA 2 DATA 3
D7 EARS3 DATD3 TACS 1 1 1
D6 EARS2 DATD2 DATAF1 0 0 1
INITIALIZING MODE 1 D5 D4 D3 D2 EARS1 EARS0 AUDEV3 AUDEV2 DATD1 DATD0 TXSEN3 TXSEN2 DATAF0 SATS TEST1 TEST0 START-UP BIT SETTINGS (TACS) 0 0 1 0 88HEX 0 0 1 0 88HEX 0 0 0 0 C2HEX
D1 AUDEV1 TXSEN1 1 0 0 1
D0 AUDEV0 TXSEN0 0 0 0 0
WORD/BIT
DATA 1 DATA 2 DATA 3 DATA 1 DATA 2 DATA 3
D7 X 0 RHF2 X 0 0
D6 X X RHF1 X X 0
HANDSFREE D5 D4 D3 X X X AMPS X X RHF0 THF2 THF1 START-UP BIT SETTINGS X X X 00HEX 0 X X 01HEX 0 0 0 03HEX
D2 0 MIG THF0 0 0 0
D1 0 HFS 1 0 0 1
D0 0 HFP 1 0 1 1
Table 25 Control Messages
30
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