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ICs for Audio Common Use
AN5270
4.3 W x 1(8) Power Amplifier with Volume Control and Tone Control
s Overview
The AN5720 is an integrated circuit designed for 4.3 W(8 ) power amplifier with volume control and tone control.
2.650.1
8.40.25 5.80.25 1.50.25 6.3 0.3 7.1 0.25
Unit : mm
3.750.25
0.10.05
* DC volume control : 0 to 5 V * DC tone control : 0 to 5 V * 9-lead single-in-line plastic package with fin
19.90.1
18.30.25
3.30.1
s Features
5.60.25
HSIP009-P-0000
s Block Diagram
Pre amp.
1 2 3
Volume control
Tone control
4
5
6
7
8
VCC1
Vol-ctl.
Tone-ctl.
RF
Out
s Pin Descriptions
Pin No. 1 2 3 4 5 6 7 8 9 VCC1 Sound input Low frequency input Volume control Tone control Ripple filter Ground Sound output VCC2 Pin Name
Note) Pins 2 and 4 are weaker in protection against positive surge than the other pins. It is necessary to pay attention during application use.
GND
VCC2
In
LF
9
1.7 0.25
1.70.25 +0.1 0.45 -0.05
9 8 7 6 5 4 3 2 1
0.5 0.1 1.2 0.25
15.0
2.54
22.30.3
1
AN5270
s Absolute Maximum Ratings
Parameter Supply voltage Symbol VCC1(V1-7) VCC2(V9-7) Circuit voltage V2-7 V3-7 V4-7 V5-7 Supply current
*3, 4 *2 *1
ICs for Audio Common Use
Ratings 14 26 0 to V9-7 0 to V9-7 0 to V1-7 0 to V1-7 15 2 -1.7 to +1.7 1.6 -20 to +70 -55 to +150
Unit V
ICC1 ICC2
mA A APP W C C
Circuit current
I8 PD Topr Tstg
*1
Power dissipation
Operating ambient temperature Storage temperature
Note) Do not apply a current or voltage from the external to the terminals that are not described above. *1 : Ta = 25 C, excluding parameters regarding ambient temperature and storage temperature. *2 : Ta = 70 C, the IC is mounted on PCB, without external heat sink. *3 : For circuit currents, '+' denotes current flowing into the IC, and '-' denotes current flowing out of the IC. *4 : As the output Pin8 does not have over current protection circuit incorporated, therefore please take precaution not to short the output pin to either VCC or GND.
s Recommended Operating Range
Parameter Operating supply voltage range Symbol VCC1 VCC2 Range 11 to 13 15 to 24 Unit V
2
ICs for Audio Common Use
AN5270
s Electrical Caracteristics at VCC1 = 12 V, VCC2 = 18 V, f = 1 kHz, Ta = 25 C, RL = 8 , Vol. = max., Tone = max.
Parameter Quiescent current 1 Quiescent current 2 Output DC bias Voltage gain Total harmonic distortion Max. output power Max. output attenuation Tone variable range Symbol ITOT1 ITOT2 VODC GV THD Pomax Attmax GTC Conditions No input signal Measure VCC1 current No input signal Measure VCC2 current No input signal Measure Pin8 DC VO = 1 Vrms, GV = 20 log(VO / VIN) VO = 1 Vrms, BPF : 400 Hz to 30 kHz THD = 10 %, PO = VO2 / RL VO = 1.0 Vrms, Vol. = max. min. Attmax = 20 log [VO(vol. = max.) / VO(vol. = min.)] f = 10 kHz, fix VIN where VO(tone = max.) = 1 Vrms Tone = max. min. GTC = 20 log [VO(tone = max.) / VO(tone = min.)] Min 7 20 7.2 28 4.0 18 Typ 10 28 8.3 30 0.5 4.3 -69 20 Max 13 48 9.4 32 1.0 -66 Unit mA mA V dB % W dB dB
s Application Circuit Example
12V
AN78M12
47F
AN5270
RF 6
GND 7
VCC1 1
Vol-ctl. 4
Tone-ctl. 5
Out 8
In 2
3
9 470 F 8 GND AN78M05 VCC2
5.1k
100 33F External audio in SIF-IC Det. out
Ext TV 100k AV 33F SW 33F 1k
24k 3.3F 30k
LF
0.039 F
47F
2200F
18V Power supply
5V 10k VR 9k 22F 33k 10k VR
33F
100F
Note) Design considerations for shock noise prevention. : In the application of the IC, please adopt the above power supply configuration whenever possible. Where this is not possible, then it is better to ensure that VCC1 should start up first before the onset of VCC2, in order to prevent power-on shock noise. Similarly, please ensure that VCC2 declines faster than VCC1, in order to prevent power-off shock noise.
3
AN5270
s Technical Information
* Characteristic curve chart PD Ta
11 10.4 10 9 4 Pmax < Tjmax - Ta Rth
2 1.7 1
ICs for Audio Common Use
Area of safe operation
10 ms single pulse, free air
Power dissipation PD (W)
8 7 6 5 4.14 4 3.36 3 2.5 2 1 0 0 20 40 60 80 100 120 140 160 3 2 1 2.15 2.63
0.5
6.65
IC (A)
25 C 0.1 0.05 70 C
1.6
0.02 0.01 1 5 10 26 50 100
Ambient temperature Ta (C)
VCE (V)
1 No heat sink 2 5.5 x 5.0 cm2 Al board (t = 1 mm) 3 7.5 x 7.5 cm2 Al board (t = 1 mm) 4 Infinity heat sink
* Structure of pre-amp. stage Pre-amp. stage Tone-control Power stage Volume-control GP (25 dB) Output 8 GT Ci
G
2.8 k Point1 GL1 47 k 2.8 k
Input 2
GF Point2 GL2
LF input 3
GB 5.6 k 1 k
33 pF
C2 VIN R1
C1
Fig. Simplified structure of AN5270 pre-amp. stage Explanation of gain notations : GT : Gain of tone-amp. (treble-amp.) GF GB : Gain of flat-response amp. : Gain of bass-amp.
GL1 : Gain at point 1 with respect to VIN. GL2 : Gain at point 2 with respect to VIN. GP : Gain of power stage. Gpre : Gain of pre-amp. stage. 4
ICs for Audio Common Use
s Technical Information (continued)
* Structure of pre-amp. stage (continued)
AN5270
GF amp., the flat-amp., amplifies the signal equally for all frequencies in the range of 20 Hz to 70 kHz. GT amp., the treble or tone-amp., has an internal LPF connected to its inverting input. The non-inverting input of GT amp. is connected to the input signal. Thus, the output of GT passes only the upper range of frequencies (cut-off frequency = 2.5 kHz). GB amp., the bass-amp., amplifies the lower range of frequencies. Its cut-off frequency is determined by R1* C1. If LF pin is left open, then GB amp. has no effect on the overall frequency response. * Gain calculation General formula for gain of pre-amp. is (when vol. = max., tone = max.) :
Gpre = GL1 * (GF + GT) - GB * GL2
By vector analysis as shown in fig. Vector diagram of Gpre, GV [dB] = Gpre + GP GV [dB] = 20 log [GL1 * (GF + GT) - GB * GL2 * cos]2 + (GB * GL2 * sin)2 + GP where GL1 = 0.5 GF = 1.3 GB = 5.4 0 for (100 Hz) GT = 1.3 for (1 kHz) 2.5 for (10 kHz) GP = 25 dB Z3 * 0.848 GB Z3 + R1 6600 Z3 = 1 + (2f * C1 * 6600)2 = -tan-1 (2f * C1 * 6600)
Gpre
GL1 * (GF + GT)
GB * GL2 Fig. Vector diagram of Gpre
GV G1 -3 dB
G2 G3 *1 -3 dB
G1 : Gain at 100 Hz G2 : Gain at 1 kHz G3 : Gain at 10 kHz f1 : High frequency cut-off when Pin3 is open. f2 : Low frequency cut-off Tone = max. Tone = min.
100 Hz f2
1 kHz f1
10 kHz
f
Fig. Frequency response of AN5270
Note) *1 : This is the response if LF pin is open (i.e. R1 open).
5
AN5270
s Technical Information (continued)
* Cut-off frequencies f1 = f2 = 1 = 2.5 kHz 2 * G * Ci * Ri 1 = 530 Hz 2 * R1 * C1
ICs for Audio Common Use
where G = 40 times, Ci = 33 pF, R1 = 47 k if R1 = 3 k, C2 = 0.1 F
* Summary of frequency characteristics for typical values of R1 and C1 Actual Gain(dB)* R1() 2.2 k 5.1k 10 k 20 k 1k 2.2 k 3k 5.1 k 10 k 20 k C1(F) 0.039 0.039 0.039 0.039 0.1 0.1 0.1 0.1 0.1 0.1 G1(100 Hz) 35.0 31.0 26.0 17.5 24.0 36.0 34.0 33.0 31.0 26.0 18.0 G2(1 kHz) 34.0 31.0 27.5 25.0 26.0 35.0 32.0 31.0 29.0 27.0 26.0 G3(10 kHz) 31.0 31.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 30.0 f2(Hz) 1.8 k 800 408 204 1.6 k 723 530 312 159 80 GTC(dB) 10.0 21.0 21.0 18.0 14.0 10.0 19.0 21.0 19.0 17.0 16.0
Note) * : Tone = max.
Table. Tabulated summary of frequency characteristics of AN5270. * Volume control The volume control range is 0 to 5 V. This range is adopted so as to simplify the pull-up of typical PWM output from micro-computer IC. The following simplified PWM output configuration is suggested : The high input impedance of the volume control pin makes the input current extremely small, so that it is not necessary to have an external buffer at the PWM output. Configuration A :
5V Volume control 4 300 Treble control 300 Fig. Volume control interface circuit for AN5270 C4 5 2.2 F R4 18 k R5 12 k PWM output Microcomputer IC
6
ICs for Audio Common Use
s Technical Information (continued)
* Volume control (continued)
AN5270
Alternative responses of volume control may be obtained by addition of a diode across the resistor R4.
Configuration B : R4 18 k Config. B A C Configuration C : R4 18 k 0 0.6 V Volume DC Pin4 (V) 5V 2.2 F 10 k 12 k 2.2 F 12 k
Volume attenuation
Fig. Volume characteristics of AN5270
* Tone control The tone cotrol range is 0 to 5 V. Please adopt the same PWM configration as suggested for the volume control. The variable range of tone control is about 20 dB, depending on the values of R1 * C1 components that are connected to Pin3. Internally, there is a LPF formed by Ri = 47 k and a Miller capacitor which is formed by Ci = 33 pF and the gain amplifier G = 40. The cut-off frequency is thus : 1 = 2.5 kHz 2 * G * Ci * Ri To achieve a rich deep-bass effect, the tone control should be adjusted to minimum (0 V). To achieve a bright treble effect, the tone control should be adjusted to maximum. * VCC requirement VCC1 should be fixed at 12 V. Achieve best performance by obtaining this supply from a 12 V voltage regulator output.
7
AN5270
s Technical Information (continued)
* Power-on/off pop-noise elimination
ICs for Audio Common Use
In most TV applications, it is observed that there is a short period of delay from power-on to the onset of sound. The purpose of power-on mute is to eliminate any unpleasant 'pop' noise (caused by transients) by effectively muting the power amplifier. In this IC, an internal mute is incorporated at the instant of power-on and power-off. The length of mute time depends on the value of the ripple filter condenser at Pin6. In the following diagram, the value of the condenser connected to RF pin (Pin6) is 47 F.
18 V VCC2 Pin9 12 V VCC1 Pin1 270 ms Internal mute-pulse 170 ms 5V Volume Pin4 1.2 s
Output Pin8 470 ms 220 ms
Fig. Power on/off typical timing characteristics of AN5270
(The above timing diagram is based on the evaluation circuit that is given in the product specification. Actual chasis performance may differ due to differences in power supply and external components.) The internal mute pulse will force the volume to minimum by grounding Pin4 momentarily. In most chasis, it is also common to implement externally the audio defeat feature by forcing Pin4 to ground momentarily, for the purpose of power-on/off as well as during channel switching. Should the internal mute be insufficient, it is recommended that the external audio defeat be used.
8
ICs for Audio Common Use
s Technical Information (continued)
* Power-off pop-noise countermeaasure (for study consideration only)
AN5270
To prevent power-off shock noise, please ensure that VCC2 (18 V) declines faster than VCC1 (12 V). In addition, to ensure that VCC1 variation will not cause any 'pop' , one suggested countermeasure is to connect a condenser between Pin6 and Pin9 (e.g. 47 F, use non-polarity type if possible).
RF 6 C6 47 F Cpop 47 F NP VCC2 9
2200 F
Fig. One suggested counter-measure against power-off 'pop' for AN5270.
This effect of Cpop is to discharge C6 gradually as soon as power is switched off. However, it must be noted that the necessity of this countermeasure is dependent upon the set design and other timing considerations. * THD improvement (for study consideration only)
1 6
47 F C6
Fig. THD improvement circuit.
Instead of connecting the negative terminal of C6 to ground, when that terminal is connected to Pin1, it is noticed that THD is improved considerably.
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