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prj 02/27/03 information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. no license is granted by implication or otherwise under any patent or patent rights of analog devices. trademarks and registered trademarks are the property of their respective companies. one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781/329-4700 www.analog.com fax: 781/326-8703 ? 2003 analog devices, inc. all rights reserved. a diversity if to baseband gsm/edge narrowband receiver preliminary technical data ad6650 features digital vga i & q demodulators active low pass filters dual wideband adc programmable decimation and channel filters phase locked loop circuitry serial data output ports if frequencies 70-300mhz 10 db noise figure +24 dbm input ip2 -13 dbm input ip3 3.3 volt i/o and cmos core i 2 c and microprocessor interface jtag boundary scan applications gsm/edge single carrier and diversity receivers micro and pico cell systems wireless local loop smart antenna systems software radios in building wireless telephony product description the ad6650 is a diversity, if to baseband receiver for gsm/edge. this narrow band receiver consists of an integrated dvga, if-to-baseband i&q demodulators, low- pass filtering, and a dual wideband adc. the chip can accommodate if input frequencies from 70 mhz to 300 mhz. this receiver architecture is designed such that only one external saw filter(one for main and one for diversity) is required in the entire rx signal path to meet gsm/edge blocking requirements. digital decimation and filtering circuitry is embedded on chip to generate serial output i&q data streams. the decimating filters remove unwanted signals and noise outside the channel of interest. in addition, programmable ram coefficient filters allow anti-aliasing, matched filtering, and static equalization functions to be combined in a single, cost- effective filter. the ad6650 is part of a complete gsm/edge receive and transmit chipset. other components in this chipset are: rf to if amplifier/mixers, receive and transmit frequency hopping synthesizers, and a baseband to if transmit modulator and ramping chip. figure 1. ad6650 functional block diagram
preliminary technical data ad6650 rev. prj 0 2/27/2003 2 table of contents features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xx product description . . . . . . . . . . . . . . . . . . . . . . . .xx functional block diagram . . . . . . . . . . . . . . .. .xx specifications/characteristics . . . . . .. . . . . . xx timing diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . xx absolute maximum ratings . . . . . . . . . . . . . . . .xx pin function descriptions . . . . . . . . . . . . . . . . xx architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xx example filter response . . . . . . . . . . . . . . . . . . .xx agc loop.......................................................................xx dc correction...........................................................xx fourth order cascaded integrator comb filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xx cic4 rejection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xx infinite impulse response xx ram coefficient filter . . . . . . . . . . . . . . . . . . . . .xx rcf decimation register . . . . . . .. . . . . .. . . . . xx rcf decimation phase . . . . .. . . . . . . . . . . . . . xx rcf filter length . . . . . .. . . . . . . . . . . . . . . . . .xx rcf output scale factor and control register . xx user-configurable built-in self-test channel bist...........................................xx chip synchronization . . . . . . . . . . . . . . . . . . . . .xx start . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . xx serial output data port . . . . . . . . . . . . . . . . . . .xx serial output data format . . . . . . . . . . . . . . . . . xx serial data frame (serial bus master) .. . . . . . . . xx serial data frame (serial cascade) . . . . . . . . . xx configuring the serial ports . . . . . . . .. . . . . . . xx serial port data rate . . . . . . . . . .. . . . . . . . . . . . xx serial slave operation . . . . . . . . . .. . . . . . . . . . . xx serial ports cascaded . . . . . . . .. . . . . . . . . . . . . . xx serial output frame timing (master and slave) xx serial port timing specifications . . . . . . ... . . . . xx sclk . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . xx sdo0 . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . xx sdo1 . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . xx sdfs . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . .. . xx serial word length . . . . . .. . . . . . . . . . . . . . . . . xx sdfs mode . . . . . . . . . . . . .. . . . . . . . . . . . . . . . xx mapping rcf data to the bist registers . . . .. . xx 0x00: clock divider control . .. . .xx 0x01-0x05: pll register[4:0] . . . . . . .. . . . . .. . xx 0x06: clamp control............................................xx 0x07: aux dac a ...............................................xx 0x08: aux dac b ................................................xx 0x09: aux dac control.......................................xx 0x0a: adc dither control.................................xx 0x0b: dc correction bw.....................................xx 0x0c: dc correction control...............................xx 0x0d-0x14: agc control[7:0]............................xx 0x15: start hold-off counter...............................xx 0x16: cic4 decimation.......................................xx 0x17: cic4 scale.................................................xx 0x18: iir control register...................................xx 0x19: rcf decimation register..........................xx 0x1a: rcf decimation phase..............................xx 0x1b: rcf coefficient offset..............................xx 0x1c: rcf taps....................................................xx 0x1d: rcf scale register...................................xx 0x1e-0x1f: bist for a-i/q.................................xx 0x20-0x21: bist for b-i/q..................................xx 0x22: serial control register...............................xx 0x23-0x29: reserved............................................xx 0x30-0x5f: coefficient memory.........................xx 0x60-0xff: reserved...........................................xx microport control . . . . . . . . . . . . . . . . . . . . . . . . xx external memory map . . . . . .. . . . . . . . . . . . . . . xx access control register (acr) . . . . .. . . . . . . . . xx external memory map . . . . . . ... . . . . . . . . . . . . xx channel address register (car) . .. . . . . . . . . . xx soft_sync control register . .. . . . . . . . . . xx pin_sync control register . . . ... . . . . . . . . . xx sleep control register . . . . . . .. . . . . . . . . . . . xx data address registers . . . . . . .. . . . . . . . . . . . . xx write sequencing . . . . . . . .. . . . . . . . . . . . . . . . . xx read sequencing . . . . . . . .. . . . . . . . . . . . . . . . . xx read/write chaining . . . . .. . . . . . . . . . . . . . . . . xx intel nonmultiplexed mode (inm) . . . . . . . . . . . xx motorola nonmultiplexed mode (mnm) ... . . . . xx i 2 c port control jtag boundary scan . . . . . . . . . . . . . . . . . . . . .xx internal write access . . . . . . . . . . . . . . . .. . . . .xx write pseudocode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xx internal read access . . . . . . . . . . . . . . . . . . . . . . xx read pseudocode . . . . . . . . . . . . . . . . . . . . . . . xx outline dimensions . . . . . . . . . . . . . .. . . . . xx
preliminary technical data ad6650 rev. prj 0 2/27/2003 3 ac specifications parameter temp test level min ad6650bbc typ max units overall function frequency range 70 300 mhz gain control gain step size .094 db gain step accuracy +/- .5 step baseband filters group delay 119 124 127 ns bandwidth 3.36 3.5 3.64 mhz lo phase noise: @ 200khz offset -88 dbc/hz @ 400khz offset -108 dbc/hz @ 600khz offset -120 dbc/hz @ 800khz offset tbd dbc/hz @ 1600khz offset tbd dbc/hz @ 3000khz offset tbd dbc/hz f = 70 mhz min gain 0 db max gain 36 db noise figure 1 10.25 db input ip2 +24 dbm input ip3 -13 dbm image rejection 35 dbc fullscale input power +4 dbm input impedance 200+jx ? f = 150 mhz min gain 0 db max gain 36 db noise figure 1 10.25 db input ip2 +24 dbm input ip3 -13 dbm image rejection 35 dbc fullscale input power +4 dbm input impedance 200+jx ? f = 200 mhz min gain 0 db max gain 36 db noise figure 1 10.25 db input ip2 +24 dbm input ip3 -13 dbm image rejection 35 dbc fullscale input power +4 dbm input impedance 200+jx ? f = 250 mhz min gain 0 db max gain 36 db noise figure 1 10.25 db input ip2 +24 dbm
preliminary technical data ad6650 rev. prj 0 2/27/2003 4 input ip3 -13 dbm image rejection 35 dbc fullscale input power +4 dbm input impedance 200+jx ? f = 300 mhz min gain 0 db max gain 36 db noise figure 1 10.25 db input ip2 +24 dbm input ip3 -13 dbm image rejection 35 dbc fullscale input power +4 dbm input impedance 200+jx ? 1 this measurement applies in maximum gain (+36 db)
preliminary technical data ad6650 rev. prj 0 2/27/2003 5 digital specifications ( tmin to tma x, avdd, clkvdd, dvdd = +3.3v, unless otherwise noted) parameter temp test level min ad6650bbc typ max units vdd iv 3.0 3.3 3.6 v vddio iv 3.0 3.3 3.6 v avdd iv 3.0 3.3 3.6 v t ambient iv -40 +25 +85 c electrical characteristics parameter (conditions) temp test level min ad6650bbc typ max units logic inputs logic compatibility full 3.3v cmos logic ?1? voltage vdd-0.9 vdd v logic ?0? voltage 0 0.9 v logic ?1? current ?10 +10 a logic ?0? current ?10 10 a input capacitance 5 pf logic outputs logic compatibility full 3.3vcmos/ttl logic ?1? voltage (i oh =0.25ma) full iv 2.4 vdd-0.2 v logic ?0? voltage (i ol =0.25ma) full iv 0.2 0.4 v idd supply current clk=104 mhz (gsm example) +25 c v i vdd ma i vddio ma i avdd ma power dissipation clk=104 mhz gsm/edge example v 1.2 w
preliminary technical data ad6650 rev. prj 0 2/27/2003 6 general timing characteristics parameter (conditions) temp test level min ad6650 typ max units clk timing requirements: t clk clk period full i 9.6 ns t clkl clk width low full iv 0.5 x t clk ns t clkh clk width high full iv 0.5 x t clk ns /reset timing requirements: t resl /reset width low full iv 30 ns sync timing requirements: t ss sync to clk setup time full iv ns t hs sync to clk hold time full iv ns master mode serial port timing requirements (sbm=1): switching characteristics 2 t dsclk1 clk to sclk delay (divide by 1) full iv 3.9 13.4 ns t dsclkh clk to sclk delay (for any other divisor) full iv 4.4 14.0 ns t dsclkl clk to sclk delay (divide by 2 or even #) full iv 3.25 6.7 ns t dsclkll clk to sclk delay (divide by 3 or odd #) full iv 3.8 6.9 ns t dsdfs sclk to sdfs delay full iv 3.02 ns t dsdo sclk to sdo delay full iv 2.7 ns t dsd1 sclk to sd1 delay full iv 2.6 ns t dsdr sclk to dr delay full iv 2.7 ns slave mode serial port timing requirements (sbm=0): switching characteristics 2 t sclk sclk period full iv 16.0 ns t sclkl sclk low time (when sdiv=1, divide by 1) full iv 5.0 ns t sclkh sclk high time (when sdiv=1, divide by 1) full iv 5.0 ns t dsdo sclk to sdo delay full iv 6.8 ns t dsd1 sclk to sd1 delay full iv 6.8 ns t dsdr sclk to dr delay full iv 6.9 ns input characteristics t ssf sdfs to sclk setup time full iv 2.6 ns t hsf sdfs to sclk hold time full iv -1.15 ns 1 all timing specifications valid over vdd range of 3.0v to 3.6v and vddio range of 3.0v to 3.6v. 2 the timing parameters for sclk, sdfs, sdo0, sdo1, and dr apply to both channels (0, 1). the slave serial port?s (sclk) operating frequency is limited to 52 mhz. 3 specification pertains to control signals: rw, (/wr), /ds, (/rd), /cs 4 (c load =40pf on all outputs unless otherwise specified)
preliminary technical data ad6650 rev. prj 0 2/27/2003 7 microprocessor port timing characteristics 1 microprocessor port, mode inm (mode=0) temp test level min ad6650 typ max units mode inm write timing: t sc t hc t hwr control 3 to clk setup time control 3 to clk hold time /wr(rw) to rdy(/dtack) hold time full full full iv iv iv 5.5 1.0 8.0 ns ns ns t sam address/data to /wr(rw) setup time full iv -0.5 ns t ham address/data to rdy(/dtack) hold time full iv 7.0 ns t drdy /wr(rw) to rdy(/dtack) delay full iv 4.0 ns t acc /wr(rw) to rdy(/dtack) high delay full iv 4*t clk 5*t clk ns mode inm read timing: t sc t hc t sam control 3 to clk setup time control 3 to clk hold time address to /rd(/ds) setup time full full full iv iv iv 4.0 2.0 0.0 ns ns ns t ham address to data hold time full iv 7.0 ns t zd data tri-state delay full iv ns t dd rdy(/dtack) to data delay full iv ns t drdy /rd(/ds) to rdy(/dtack) delay full iv 4.0 ns t acc /rd(/ds) to rdy(/dtack) high delay full iv 4*t clk 7*t clk ns microprocessor port, mode mnm (mode=1) temp test level min ad6650 typ max units mode mnm write timing: t sc t hc t hds control 3 to clk setup time control 3 to clk hold time /ds(/rd) to /dtack(rdy) hold time full full full iv iv iv 5.5 1.0 8.0 ns ns ns t hrw rw(/wr) to /dtack(rdy) hold time full iv 8.0 ns t sam address/data to rw(/wr) setup time full iv -0.5 ns t ham address/data to rw(/wr) hold time full iv 7.0 ns t ddtack /ds(/rd) to /dtack(rdy) delay full iv ns t acc rw(/wr) to /dtack(rdy) low delay full iv 4*t clk 5*t clk ns mode mnm read timing: t sc t hc t hds control 3 to clk setup time control 3 to clk hold time /ds(/rd) to /dtack(rdy) hold time full full full iv iv iv 4.0 2.0 8.0 ns ns ns t sam address to /ds(/rd) setup time full iv 0.0 ns t ham address to data hold time full iv 7.0 ns t zd data tri-state delay full iv ns t dd /dtack(rdy) to data delay full iv ns t ddtack /ds(/rd) to /dtack(rdy) delay full iv ns t acc /ds(/rd) to /dtack(rdy) low delay full iv 4*t clk 7*t clk ns mode i 2 c timing: t dscl scl to sda delay full iv 61 ns t dsda sda to scl delay full iv 57 ns t sscl 5 clk to scl delay full iv 5 ns 1 all timing specifications valid over vdd range of 3.0v to 3.6v and vddio range of 3.0v to 3.6v. 2 the timing parameters for sclk, sdfs, sdo0, sdo1, and dr apply to both channels (0, 1) 3 specification pertains to control signals: rw, (/wr), /ds, (/rd), /cs 4 (c load =40pf on all outputs unless otherwise specified) 5 there is no hold time for sda because as this waits for a negative transition ( ) on scl to transition.
preliminary technical data ad6650 rev. prj 0 2/27/2003 8 timing diagrams reset t ssf figure x. reset timing requirements sclk clk t dsclkh t sclkl t sclkh figure x. sclk switching characteristics (divide by 1) sclk clk t dsclkh t dsclkl figure x. sclk switching characteristics (divide by 2 or even integer) sclk clk t dsclkh t dsclkll figure x. sclk switching characteristics (divide by 3 or odd integer)
preliminary technical data ad6650 rev. prj 0 2/27/2003 9 timing diagrams sdi sdfs sclk t dsdfs t ssi t hsi datan figure x. serial port switching characteristics dr clk t ddr figure x. clk, dr switching characteristics dr sclk t dsdr figure x. sclk, dr switching characteristics t ssf t hsf sclk sdfs figure x. sdfs timing requirements (sbm=0)
preliminary technical data ad6650 rev. prj 0 2/27/2003 10 timing diagrams sync clk t ss t hs figure x. sync timing inputs timing diagrams ? inm microport mode t sam /rd (/ds) /wr (rw) /cs a[2:0] d[7:0] rdy (/dtack) valid address valid data t sam t ham t ham t drdy t hwr t acc notes: 1. t acc access time depends on the address accessed. access time is measured from fe of /wr to re of rdy. t acc requires a maximum of 9 clk periods t sc t hc clk figure 16. inm microport write timing requirements. t sam /rd (/ds) /wr (rw) /cs a[2:0] d[7:0] rdy (/dtack) valid address t zd t dd t drdy t zd t acc valid data t ha notes: 1. t acc access time depends on the address accessed. access time is measured from fe of /wr to re of rdy. t acc requires a maximum of 13 clk periods and applies to a[2:0]=7,6,5,3,2,1 t sc t hc clk figure 17. inm microport read timing requirements.
preliminary technical data ad6650 rev. prj 0 2/27/2003 11 timing diagrams ? mnm microport mode t sam /ds (/rd) rw (/wr) /cs a[2:0] d[7:0] /dtack (rdy) valid address valid data t sam t ham t ham t hrw t acc t hds t ddtack notes: 1. t acc access time depends on the address accessed. access time is measured from the fe of /ds to the fe of /dtack. t acc requires a maximum of 9 clk periods t sc t hc clk figure x. mnm microport write timing requirements. t sam /ds (/rd) rw (/wr) /cs a[2:0] d[7:0] /dtack (rdy) valid address t zd t dd t zd t hds t acc valid data t ha t ddtack notes: 1. t acc access time depends on the address accessed. access time is measured from the fe of /ds to the fe of /dtack. t acc requires a maximum of 13 clk periods t sc t hc clk figure x. mnm microport read timing requirements.
preliminary technical data ad6650 rev. prj 0 2/27/2003 12 absolute maximum ratings 1 supply voltage?????.?????.....-0.3v to 3.3v input voltage???..???.........................-0.3 to 3.6v output voltage swing????..-0.3v to vddio +0.3v load capacitance???????..?????.200pf junction temperature under bias?..?.???.+125 c storage temperature range???.......-65 c to +150 c lead temperature (5 sec)????..???.?..+280 c notes 1 stresses greater than those listed above may cause permanent damage to the device these are stress ratings only; functional ope ration of the devices at these or any other conditions greater than those indicated in the operational sections of this specification is not implied. exposure to abs olute maximum rating conditions for extended periods may affect device reliability. thermal characteristics 121-pin ball grid array: ja =28.1 c /watt, no airflow ja =xx c/watt, 200-lfpm airflow thermal measurements made in the horizontal position on a 4-layer board . explanation of test levels i 100% production tested. ii 100% production tested at 25 c, and sampled tested at specified temperatures. iii sample tested only iv parameter guaranteed by design and analysis v parameter is typical value only vi 100% production tested at 25 c, and sampled tested at temperature extremes ordering guide model temperature range package description package option ad6650bbc 1 -40 c to +85 c (ambient) 121- pin ball grid array ad6650/pcb evaluation board with ad6650 and software notes 1 x-grade material is pre-production material, normally shipped during product characterization and qualification. esd sensitivity the ad6650 is an esd (electrostatic discharge) sensitive device. electrostatic charges as high as 4000 v readily accumulate on the human body and test equipment and can discharge without detection. although the ad6650 features proprietary esd protection circuitry, permanent damage may occur on devices subjected to high-energy electrostatic discharges. therefore, prop er esd precautions are recommended to avoid performance degradation or loss of functionality.
preliminary technical data ad6650 rev. prj 0 2/27/2003 13 pin configuration 1 2 3 4 5 6 7 8 9 10 11 a dgnd tdi tms /trst /reset dnc avdd clk /clk agnd agnd a b sdfs sclk tdo tclk sync dnc avdd avdd agnd agnd /bin b c sd1 sd0 dvdd dvdd dvdd dvdd avdd avdd agnd agnd bin c d d7 dr dvdd dgnd dgnd dgnd avdd avdd agnd agnd agnd d e d5 d6 dvdd dgnd dgnd dgnd avdd avdd agnd agnd lf e f d3 d4 dvdd dgnd dgnd dgnd avdd avdd agnd xvcob xvco f g d1 d2 dvdd dgnd dgnd dgnd avdd avdd agnd agnd cp g h /ds d0 dvdd dgnd dgnd dgnd avdd avdd agnd agnd agnd h j rw /dtack dvdd dvdd dvdd dvdd avdd avdd agnd agnd ain j k a2 a1 /cs mode1 chip_id1 dnc avdd refgnd reft agnd /ain k l dgnd a0 mode2 mode0 chip_id0 dnc avdd vref refb agnd agnd l 1 2 3 4 5 6 7 8 9 10 11 pin function descriptions name type function # of pins power supply dvdd p 3.3v digital core/io supply 13 avdd p 3.3v analog supply 9 dgnd g digital ground 17 agnd g analog ground 22 inputs /reset i active low reset pin 1 sync i synchronizes digital filters and agc loop 1 chip_id[1:0] i chip id 2 serial data port sclk i/o bi-directional serial clock 1 sdfs i/o bi-directional serial data frame sync 1 sd0 o/t serial data output 1 sd1 o/t serial data output 1 dr o output data ready indicator 1 1 microport/serial control 2 d[7:0] i/o/t bi-directional microport data 8 a[2:1] i microport address bits 2 and 1 2 a0 i/o/t microport adress bit 0 1 /cs i chip select 1 /ds(/rd) i/o/t active low data strobe (active low read) 1 /dtack(rdy) i/o/t active low data acknowledge (microport status bit) 1 rw(/wr) i/o/t read write (active low write) 1 mode[2:0] i selects control port mode 3 jtag /trst i test reset pin 1 tclk i test clock input 1 tms i test mode select input 1
preliminary technical data ad6650 rev. prj 0 2/27/2003 14 tdo o/t test data output 1 tdi i test data input 1 analog inputs ain i main analog input 1 ain/ i complement of ain, differential analog input 1 bin i diversity analog input 1 bin/ i complement of bin, differential analog input 1 pll inputs cpout o charge pump out 1 lf i loop filter xvco i external vco input [no connection required if internal vco used] 1 xvcob i external vco input complement [no connection required if internal vco used] 1 reft; refb; vref o internal adc voltage reference; bypass to ground with capacitor[3]; see schematic for proper hook-up 3 refgnd g adc ground reference; see schematic for proper hook-up clock inputs clk i encode input, conversion initiated on rising edge 1 clk/ i complement of encode 1 dnc n/a do not connect 4
preliminary technical data ad6650 rev. prj 0 2/27/2003 15 architecture the ad6650 is a mixed-signal received signal processor intended for direct if sampling radios requiring high symbol rate. it has been optimized for the demanding filtering requirements of gsm and edge. the ad6650 has five signal processing stages: a digital vga, i&q demodulators, 7 th order low pass filters, dual wideband adc, and digital filtering and control stage. programming and control is accomplished via serial and microprocessor interfaces. dvga a gain ranging digital vga is used to extend the dynamic range of the input signal and prevent signal clipping at the adc input. i&q demodulators frequency translation is accomplished with i&q demodulators. real data entering this stage is separated into in-phase (i) and quadrature (q) components. this stage translates the input signal from an intermediate frequency (if) to a baseband frequency. low pass filters following frequency translation is a 7 th order low pass active filter with a 3.5 mhz bandwidth and rc calibration. dual adcs the adc is implemented by providing dual track and holds in front of an ad9238 adc core. in front of each adc is a mux operating at 52 msps. vco/pll a voltage controlled oscillator and phase locked loop circuit generates the appropriate if frequency for the demodulators. digital filters following the analog frequency translation is a fourth order cascaded integrator comb (cic4) filter whose response is defined by the decimation rate. iir stage next the final stage is a sum-of-products fir filter with programmable 20-bit coefficients, and decimation rates programmable from 1 to 4. the ram coefficient fir filter (rcf in the functional block diagram) can handle a maximum of 48 taps. the overall filter response for the ad6650 is the composite of all decimating. each successive filter stage is capable of narrower transition bandwidths but requires a greater number of clk cycles to calculate the output. more decimation in the first filter stage will minimize overall power consumption. data from the chip is interfaced to the dsp via a high-speed synchronous serial port. theory of operation agc loop the agc consists of three gain control loops; a slow loop following the adc, a fast attack (fa) loop following the base band filter, and the fast decay (fd) loop following the decimation filters. slow loop the slow loop is the main loop and has a ?loop gain? parameter (p4 1 ) associated with it. this parameter controls the rate of change of the gain and should always be less than 1. the default loop gain used is 1/256. the slow loop attempts to maintain the signal entering the adc at a given level, which is referred to as the ?requested level? (p5). this level is specified to the loop in dbfs. this level can be between 0dbfs and ?24dbfs of the converter in .094db resolution. the default value is ?6.02 dbfs. the slow loop has a ?peak detect? function, the period of which can be set by the user (p1). this ?peak detect? period can be set to 1/4 of a symbol period or greater to prevent the agc loop from gaining off the envelope of the edge signal. this works since the peak detector works off of the function db(max(|i|,|q|)) which reflects all of the iq samples back into one quadrant of the iq plane. at a 26mhz sampling frequency, 1 symbol period turns out to be 96 clock cycles; therefore, to obtain a peak detect period of 1/4 symbol, the period should be set to 24 samples. fast attack loop the fa loop is based off of an analog threshold detector that prevents overdrive of the analog signal path. in a situation that could potentially overdrive the converter, the fa loop takes over from the slow loop and decreases the gain to the vga front end. the step size used for the fa loop is programmable between 0 and 1.504db in .094 db steps(p0). the fa loop also has a counter, which is programmable between 1 and 16. when initialized to ?count+1?, the fa loop decreases the gain for ?count+1? clock cycles when the threshold is crossed.
preliminary technical data ad6650 rev. prj 0 2/27/2003 16 fast decay loop the fast decay (fd) loop is a fast loop that increases the gain when the signal falls below a threshold during a deep channel fade or on the ramp down. the fast loop accomplishes this task by looking at two outputs. the first is the peak signal plus blocker level at the adc output (which includes the signal and any blockers that may be passed through by the saw filter). the second is the peak signal level after the decimation filters and a blocker reject filter have attenuated the blockers. there are two programmable levels that determine when this loop is activated: the signal plus blocker level (spb_level) and the signal level (sig_level). both these levels are defined in dbfs. default values stand at ?40dbfs for the spb_level and ? 60dbfs for the sig_level. when the ?wideband? signal is below the spb level (p12) and ?narrowband? information is below the signal level (p13), the fd loop is activated. this loop overrides the slow loop and has a programmable step size (p7) (currently set at 0.094db) and a programmable peak detect period (p6) currently set at 4 samples at 1.08mhz. fourth order cascaded integrator comb filter the cic4 processing stage implements a sharp fixed- coefficient decimating filter, which is driven by the 12 bit analog to digital converter. the maximum input rate into this filter is adc output , which cannot exceed 26 mhz. the decimation ratio, mcic4, may be programmed from 8 to 32 (all integer values). the frequency response of the filter is given by equation x. the gain and passband droop of cic4 should be calculated by these equations. both parameters may be compensated for in the iir stage. 4 1 4 1 1 1 ) ( 4 4 ? ? ? ? ? ? ? ? 4 4 4 sin sin 1 ) ( 4 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? the scale factor, sci c4 is a programmable unsigned integer between 12 and 20. it serves to control the attenuation of the data into the cic4 stage in 6 db increments. for the best dynamic range, scic4 should be set to the smallest value possible (lowest attenuation) without creating an overflow condition.

12 log 4 2 5 m ceil s cic the output rate of this stage is given by equation x. 4 4 cic output samp m adc f cic4 rejection table xx illustrates the amount of bandwidth in percentage of the clock rate that can be protected with various decimation rates and alias rejection specifications. the maximum input rate into the cic4 is 26 mhz, as mentioned above. as in table xx, these are the ? bandwidth characteristics of the cic4. table x. ssb cic4 alias rejection table -50 -60 -70 -80 -90 -100 8 2.602 2.751 2.867 2.957 3.027 3.080 9 2.311 2.444 2.547 2.627 2.690 2.737 10 2.078 2.199 2.291 2.364 2.420 2.463 11 1.889 1.998 2.083 2.148 2.200 2.239 12 1.731 1.831 1.909 1.969 2.016 2.052 13 1.597 1.690 1.761 1.817 1.861 1.894 14 1.483 1.569 1.635 1.687 1.728 1.759 15 1.384 1.464 1.526 1.575 1.613 1.641 16 1.297 1.373 1.431 1.476 1.512 1.539 17 1.221 1.292 1.346 1.389 1.423 1.448 18 1.153 1.220 1.272 1.312 1.344 1.368 19 1.092 1.156 1.205 1.243 1.273 1.296 20 1.037 1.098 1.144 1.181 1.209 1.231 21 0.988 1.045 1.090 1.124 1.152 1.172 22 0.943 0.998 1.040 1.073 1.099 1.119 23 0.902 0.954 0.995 1.027 1.051 1.070 24 2.602 2.751 2.867 2.957 3.027 3.080 25 0.830 0.878 0.915 0.944 0.967 0.985 26 0.798 0.844 0.880 0.908 0.930 0.947 27 0.768 0.813 0.847 0.874 0.896 0.912 28 0.741 0.784 0.817 0.843 0.864 0.879
preliminary technical data ad6650 rev. prj 0 2/27/2003 17 29 0.715 0.757 0.789 0.814 0.834 0.849 30 0.691 0.732 0.763 0.787 0.806 0.820 31 0.669 0.708 0.738 0.762 0.780 0.794 32 0.648 0.686 0.715 0.738 0.756 0.769 this table helps to calculate an upper bound on decimation, mcic4, given the desired filter characteristics. infinite impulse response filter the iir filter of the ad6650 is a 7 th order low-pass filter with an infinite impulse response. the z-transform and coefficients of this filter are shown below. xx_trunc z () n 0 z 7 n 2 z 5 n 3 z 3 n 1 z n 1 z 6 n 3 z 4 n 2 z 2 n 0 ? ? ? ? d 7 z 7 d 5 z 5 d 3 z 3 d 1 z ? ? ? ? 2 n 0.046227 0.278961 0.76021 1.208472 ? ? ? ? ? ? ? ? ? ? d 0 0.012895 0 0.254698 0 1.026276 0 1 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ram coefficient filter the final signal processing stage is a sum-of-products decimating filter with programmable coefficients, see figure x. the data memories i-ram and q-ram store the 24 most recent complex samples from the previous filter stage with 23- bit resolution. the coefficient memory, cmem, stores up to 48 coefficients with 20-bit resolution. on every clk cycle, one tap for i and one tap for q are calculated using the same coefficients. the rcf output consists of 16 or 24-bit data bits. rcf decimation register each rcf channel can be used to decimate the data rate. the decimation register is a 2 bit register and can decimate from 1 to 4. the rcf decimation is stored in 0x18 in the form of m rcf -1. the input rate to the rcf is f sampiir . rcf decimation phase register the ad6650 filter channel uses the value stored in this register to pre-load the rcf counter. therefore instead of starting from 0, the counter is loaded with this value, thus creating an offset in the processing that should be equivalent to the required processing delay. this data is stored in 0x19 as a 2-bit number. rcf filter length the maximum number of taps this filter can calculate, n taps , is given by the equation below. the value n taps -1 is written to the channel register within the ad6650 at address 0x1b. ? ? ? ? ? ? ? ? 48 , min sampiir rcf clk taps f m f n the rcf coefficients are located in addresses 0x40 to 0x6f and are interpreted as 20-bit 2?s complement numbers. when writing the coefficient ram, the lower addresses will be multiplied by relatively older data from the iir and the higher coefficient addresses will be multiplied by relatively newer data from the iir. the coefficients need not be symmetric and the coefficient length, n taps , may be even or odd. if the coefficients are symmetric, then both sides of the impulse response must be written into the coefficient ram. the rcf stores the data from the iir into a 46x24 ram. 23x24 is assigned to i data and 23x24 is assigned to q data. the rcf uses the ram as a circular buffer, so that it is difficult to know in which address a particular data element is stored. to avoid start-up transients due to undefined data ram values, the data ram should be cleared upon initialization. when the rcf is triggered to calculate a filter output, it starts by multiplying the oldest value in the data ram by the first coefficient, which is pointed to by the rcf coefficient offset register (0x1a). this value is accumulated with the products of newer data words multiplied by the subsequent locations in the coefficient ram until the coefficient address rcf off +n taps -1 is reached. coefficient address impulse response data 0 h(0) n(0) oldest 1 h(1) n(1) 2 =(n taps - 1) h(2) n(2) newest table xx. three-tap filter the rcf coefficient offset register can be used for two purposes. the main purpose of this register is to allow for multiple filters to loaded into memory and selected simply by changing the offset as a pointer for rapid filter changes. the other use of this register is to form part of symbol timing adjustment. if the desired filter length is padded with zeros on the ends, then the starting point can be adjusted to form slight delays in when the filter is computed with reference to the high-speed clock. this allows for vernier adjustment of the symbol timing. course adjustments can be made with the rcf decimation phase.
preliminary technical data ad6650 rev. prj 0 2/27/2003 18 the output rate of this filter is determined by the output rate of the iir stage and m rcf . rcf sampiir sampr m f f rcf output scale factor and control register register 0x1c is used to configure the scale factor for rcf filter. this 2 bit register is used to scale the output data in 6 db increments. the possible output scales range from 0 to ? 18 db. 13 9.75 6.5 3.25 0 3.25 6.5 9.75 13 100 90 80 70 60 50 40 30 20 10 0 cic4 response, mcic4 = 24 offset from channel center, mhz rejection, dbc 1.98 1.46 0.94 0.43 0 0.61 1.13 1.65 2.17 120 110 100 90 80 70 60 50 40 30 20 10 0 gemini digital composite response cic4 response iir filter response composite digital response with 8x rate frequency in mhz .17
preliminary technical data ad6650 rev. prj 0 2/27/2003 19 serial output data port the ad6650 has two configurable serial output ports (sdo0, sdo1). both ports must be configured the same and programmed using the same control register. the ports also share a common sfds, sclk, and dr pin for connection to an external asic or dsp. as such, the outputs may be configured as either serial master or serial slave, but cannot be programmed independently. serial output data format the ad6650 utilizes a normal linear binary data format with serial data frame word lengths of 16- or 24-bit precision. in this mode, the data is shifted out of the device in big endian format (msb first). serial data frame sync (serial bus master) the serial data frame is initiated with the serial data frame sync (sdfs). as each channel within the ad6650 completes a filter cycle, data is transferred into the serial data buffer. in the serial bus master (sbm) mode, the internal serial controller initiates the sdfs on the next rising edge of the serial clock. in the ad6650, there are 3 or 4 modes in which the frame sync may be generated as a serial bus master. in the case where both a and b input channels are processed through sdo0 only, there are four modes, and when a and b input channels are output through sdo0 and sdo1 respectively, there are three modes of operation (mode 0 and 1 are the same). these modes are described in section sdfs modes. serial data frame (serial cascade) any of the ad6650 serial outputs may be operated in the serial cascade mode (serial slave). in this mode, the selected ad6650 channel requires that an external device such as a dsp to issue the serial clock and sdfs. to operate successfully in the serial cascade mode, the dsp must have some indication that the ad6650 channel?s serial buffer is ready to send data. this is indicated by the assertion of the dr. this pin should be tied to an interrupt or flag pin of the dsp. in this manner, the dsp will know when to service the serial port. when the dsp begins handling the serial service, the serial port should be configured such that the sdfs pin is asserted one clock cycle prior to shifting data. as such, the ad6650 channel samples the sfds pin on the rising edge of the serial clock. on the next rising edge of the serial clock the ad6650 serial port begins shifting data until the specified number of bits have been shifted. configuring the serial ports both serial output ports can either function as a master or slave, but they cannot be set independently. a serial bus master will provide sclk and sdfs outputs. serial ports 0 and 1 will always default to serial slaves when reset is taken low, but the serial ports can be programmed to become master by setting the sbm bit in the serial control register high. serial port data rate if the serial ports are defined as a master, the sclk frequency is defined by equation x. fclk is the frequency of the master clock of the ad6650 channel and sdiv is the serial division word for the channel. the sdiv for serial port 0 and 1 can be programmed via the internal control register 0x22. serial slave operation the ad6650 can also be operated as a serial bus slave. in this configuration, shown in figure x, the serial clock provided by the dsp can be asynchronous with the ad6650 clock and input data in this mode the clock has a maximum frequency of 52 mhz and must be fast enough to read the entire serial frame prior to the next frame coming available. the ad6650 output is derived (via the decimation/interpolation rates) from its input sample rate, so the user can determine the output rate. the output rate of the ad6650 is given below. serial ports cascaded serial output ports may be cascaded on the ad6650. this allows data to be shifted out of the master and slave channel in parallel. to accomplish this, the sdfs signal of the master channel drives the sdfs input of the slave channel using the ad6650 master/slave mode permits a dsp to shift the data from the master ad6650 serial port, in parallel with a frame of data (i and q words) from the ad6650 slave port. as shown in figure xx, the master port is serial port 0. the slave port is serial port 0 and 1 from another ad6650. the only limit to the number of ports that can be cascaded comes from serial bandwidth and fan-out considerations. there must be enough serial clock cycles available to shift the necessary data into the dsp, and the sclk (common to all channels and dsp) must be closely monitored to ensure that it is a clean signal. serial output frame timing (master and slave) the sdfs signal transitions accordingly depending on whether the part is in master (sbm = 1, figure xx) or slave (sbm = 0, figure xx) mode. the next rising edge of sclk after this occurs will drive the first bit of the serial data on the sdo pin. the falling edge of sclk or the subsequent rising edge can then be used by the dsp to sample the data until the required number of bits is received (determined by the serial output port word length). if the dsp has the ability to count bits, the dsp will know when the complete frame is received.
preliminary technical data ad6650 rev. prj 0 2/27/2003 20 serial port timing specifications whether the ad6650 serial channel is operated as a serial bus master or as a serial slave, the serial port timing is identical. figures xx to xx indicate the required timing for each of the specification. t sclk t sclkl t sclkh sclk figure xx. sclk timing requirements sclk clk t dsclkh t sclkl t sclkh figure xx. sclk switching characteristics (divide by 1) t dsdo sclk sdo i 15 i 14 i 13 ..... figure xx. serial output data switching characteristics t ssf t hsf sclk sdfs figure xx. sdfs timing requirements (sbm=0) sclk sdfs sdo sdfs minimum width is one sclk i ms b i msb - 1 first data is available the first rising sclk after sdfs goes high t dso figure xx. timing for serial output port (sbm=1) sclk sclk is an output when sbm is high; sclk is an input when sbm is low in serial slave mode. all outputs are switched on the rising edge of sclk. the sdfs pin is sampled on the falling edge of sclk. this allows the ad6650 to recognize the sdfs in time to initiate a frame on the very next sclk rising edge. the maximum speed of this port is 52 mhz. sdo sdo is the serial data output. serial output data is shifted on the rising edge of sclk. on the very next sclk rising edge after an sdfs, the msb of the i data from the channel is shifted. on every subsequent sclk edge a new piece of data is shifted out on the sdo pin until the last bit of data is shifted out. the last bit of data shifted is the lsb of the channels q data. sdo is three-stated when the serial port is outside its time-slot. this allows the ad6650 to share the sdin of a dsp with other ad6650s or other devices. sdfs sdfs is the serial data frame sync signal. sdfs is an output when is high in the master mode. sdfs is an input when sbm is low in the slave mode. sdfs is sampled on the falling edge of sclk. when sbm is sampled low, the ad6650 serial port will function as a serial slave. in this mode, the port is silent until the dsp issues a frame sync. when the ad6650 detects an sdfs on the falling edge of a dsp-generated serial clock, on the next rising edge of the serial clock, the ad6650 enables the output driver and shifts the msb of the i word. data is shifted until the lsb of the q word has been sent. when sbm is sampled high, the chip functions as a serial bus master. in this mode, the ad6650 is responsible for generating serial control data. four modes of that operation are set via channel address 0x22 bits 6?5. serial word length bit 4 of register 0x22 determine the length of the serial word (i or q). if this bit is set to ?0,? each word is 16 bits (16 bits for i and 16 bits for q). if this bit is set to ?1,? the serial words are 24 bits wide.
preliminary technical data ad6650 rev. prj 0 2/27/2003 21 sdfs modes as mentioned in the section above, serial data frame sync, there are either 3 or 4 modes of operation depending on how the output of the ad6650 is configured. setting bit 7 of register 0x22 high indicates that input channel a data is output on sdo0 and input channel b is output on sdo1. in this condition there are 3 modes of operation (there are technically 4 modes, but mode 0 and 1 are the same): mode 0 and 1 (0x22 bits 6?5:00; bit 7:1): the sdfs is valid for one complete clock cycle prior to the data shift. this single pulse is valid for output channel sdo0 and sdo1. on the next clock cycle, the ad6650 begins shifting out the digitally processed data stream. depending on the bit precision of the serial configuration, either 16, or 24 bits of i data are shifted out, followed by 16 or 24 bits of q data. mode 2 (0x22 bits 6?5:10; bit 7:1): since both sdo0 and sdo1 are used, sdfs pulses high one clock cycle prior to i data and also pulses high one clock cycle prior to q data for each corresponding input channel. in this mode, there will be 2 sfds pulses per each output channel. mode 3 (0x22 bits 6?5:11; bit 7:1): the sdfs is high for the entire time that valid bits are being shifted. on sdo0 this will be either 16 or 24 bits of i data, followed by 16 or 24 bits of q data corresponding to input channel a and for sdo1, sdfs remains high for 16 or 24 bits of i data, followed by 16 or 24 bits of q data corresponding to input channel b. the sdfs bit goes high one complete clock cycle before the first bit shifted out of the ad6650. setting bit 7 of register 0x22 low indicates that input channel a and b data will be output to sdo0 only. in this condition there are 4 modes of operation: mode 0 (0x22 bits 6?5:00; bit 7:0): the sdfs is valid for one complete clock cycle prior to the data shift. there is only a single pulse for both a and b input channels. on the next clock cycle, the ad6650 begins shifting out the digitally processed data stream onto sdo0. depending on the bit precision of the serial configuration, either 16, or 24 bits of i data, followed by 16 or 24 bits of q data are shifted out corresponding to input channel a and then either 16, or 24 bits of i data, followed by 16 or 24 bits of q data corresponding to input channel b are shifted out. mode 1 (0x22 bits 6?5:01; bit 7:0): the sdfs bit goes high one clock cycle prior to the actual data associated with analog input channel a. when the i and q data stream is complete, a second sdfs is inserted one clock cycle prior to the shift of the data associated with analog input channel b. mode 2 (0x22 bits 6?5:10; bit 7:0): sfds will go high for one complete clock cycle prior to i data and a second sdfs is inserted one clock cycle prior to the shift of the first q bit, both corresponding to channel a input data. a third and fourth sdfs are inserted a clock cycle prior to the shift of i and q data respectively, which corresponds to input channel b data. in this mode there will be a total of 4 sfds pulses. mode 3 (0x22 bits 6?5:11; bit 7:0): the sdfs is high for the entire time that valid bits are being shifted, and goes high one complete clock cycle before the first bit is shifted out of the ad6650. on sdo0 there will either 16 or 24 bits of i data, followed by 16 or 24 bits of q data, then 16 or 24 bits of i data, followed by 16 or 24 bits of q data corresponding to input channel a and b respectively. microport control the ad6650 has an 8-bit microprocessor port and 4 serial input ports. the use of each of these ports is described separately below. the interaction of the ports is then described. the microport interface is a multi-mode interface that is designed to give flexibility when dealing with the host processor. there are two modes of bus operation: intel non- multiplexed mode (inm), and motorola non-multiplexed mode (mnm). the mode is selected based on host processor and which mode is best suited to that processor. the micro-port has an 8-bit data bus (d[7:0]), 3-bit address bus(a[2:0]), 3 control pins lines (/cs, /ds or /rd, rw or /wr), and one status pin (dtack or rdy). the functionality of the control signals and status line changes slightly depending upon the mode that is chosen. refer to the timing diagrams and the following descriptions for details on the operation of both modes. external memory map the external memory map is used to gain access to the channel address space. the 8-bit data and address buses are used to set the 8 registers that can be seen in the following table. these registers are collectively referred to as the external interface registers since they control all accesses to the channel address space as well as global chip functions. the use of each of these individual registers is described below in detail.
preliminary technical data ad6650 rev. prj 0 2/27/2003 22 external memory map a[2:0] name comment 111 access control register (acr) 7: auto increment 6: broadcast 5-2: instruction[3:0] 1-0: a[9:8] 110 channel address register (car) 7-0: a[7:0] 101 special function register 2 (sf2) 6: agc sync enable 5: dc correction sync enable 4: pn sync enable 3-1: reserved 0: issue soft sync 100 special function register 1 (sf1) 5: first sync only 4: enable edge-sensitivity 3-1: reserved 011 special function register 0 (sf0) 7-4: reserved 3: status of channel b 2: enable channel b 1: status of channel a 0: enable channel a 010 data register 2 (dr2) 7-4: reserved 3-0: d[19:16] 001 data register 1 (dr1) 15-8: d[15:8] 000 data register 0 (dr0) 7-0: d[7:0] table xx. external memory map access control register (acr) the access control register serves to define the channel or channels that receive an access from the micro-port or i 2 c port. bit 7 of this register is the auto-increment bit. if this bit is a 1 then the car register described below will increment its value after every access to the channel. this allows blocks of address space such as coefficient memory to be initialized more efficiently. bit 6 of the register is the broadcast bit and determines how bits 5-2 are interpreted. the broadcast bit should be set high so that bits 5-2, which are referred to as instruction bits (instruction [3:0]), allows a single or multiple (up to 4) ad6650 chip(s) to be configured simultaneously there are 10 possible instructions that are defined in the table below. the x?s in the table represent don?t cares in the digital decoding. microport instructions instruction comment: 0000 all chips will get the access. 0001 all chips will get the access. 0010 all chips will get the access. 0100 all chips will get the access. 1000 all chips with chip_id[0] =xxx 0 will get the access. 1 1001 all chips with chip_id[0] = xxx1 will get the access. 1 1100 all chips with chip_id[1:0] = xx00 will get the access. 1 1101 all chips with chip_id[1:0] = xx01 will get the access. 1 1110 all chips with chip_id[1:0] = xx10 will get the access. 1 1111 all chips with chip_id[1:0] = xx11 will get the access. 1 1 a[9:8] bits control which channel is decoded for the access. table xx. microport instructions when broadcast is enabled (bit 6 set high) read back is not valid because of the potential for internal bus contention. therefore, if read back is subsequently desired, the broadcast bit should be set low. bits 1-0 of this register are address bits that decode which of the two channels are being accessed. because the channels of the ad6650 cannot be programmed independently, these bits should be set to 0. channel address register (car) this register represents the 8-bit internal address of each channel. if the auto-increment bit of the acr is 1 then this value will be incremented after every access to the dr0 register, which will in turn access the location pointed to by this address. the channel address register cannot be read back while the broadcast bit is set high. special function registers the ad6650 has three special function registers, sf0, sf1, and sf2 that control synchronizing and enabling the channels. sf0 is the channel enable register, sf1 is the pin- sync register, and sf2 is the soft-sync register. for sf0, bits 0 and 2 allow the channels a and b, respectively to come out of sleep based on the method selected in sf1.bits 1 and 3 are read-only and indicate whether or not channels a and b, respectively are active. a 1 indicates the channel is active and a 0 indicates it is not active. bits 4 through 7 are unused. for sf1, if bit 0 is set to 1,then both channels will wait for a pulse to appear on the sync pin before coming out of sleep; otherwise, the channels will assume a soft start is desired and wait for the start hold-off counter to issue a sync. when bit 5 is set, both channels ignore all subsequent attempts to resync once they are awake. for sf2, bit 0 tells the startup block to run the start hold-off counter from the value programmed into the start hold-off counter control register and issue a sync when done. bits 4-
preliminary technical data ad6650 rev. prj 0 2/27/2003 23 6 can be used to enable syncs to individual blocks in the channels. data address registers external address [2-0] form the data registers dr2, dr1 and dr0 respectively. all internal data words have widths that are less than or equal to 20 bits. accesses to external address [0] dr0 trigger an internal access to the ad6650 based on the address indicated in the acr and car. thus during writes to the internal registers, external address [0] dr0 must be written last. at this point data is transferred to the internal memory indicated in a[9:0]. reads are performed in the opposite direction. once the address is set, external address [0] dr0must be the first data register read to initiate an internal access. dr2 is only 4 bits wide. data written to the upper 4 bits of this register will be ignored. likewise reading from this register will produce only 4 lsbs. write sequencing writing to an internal location is achieved by first writing the upper two bits of the address to bits 1 through 0 of the acr. bits 7:2 may be set to select the channel as indicated above. the car is then written with the lower eight bits of the internal address (it doesn?t matter if the car is written before the acr as long as both are written before the internal access). data register 2, (dr2) and register 1 (dr1) must be written first because the write to data register dr0 triggers the internal access. data register dr0 must always be the last register written to initiate the internal write. read sequencing reading from the micro port is accomplished in the same manner. the internal address is set up the same way as the write. a read from data register dr0 activates the internal read, thus register dr0 must always be read first to initiate an internal read followed by dr1and dr2. this provides the 8 lsbs of the internal read through the micro port (d[7:0]). additional data registers can be read to read the balance of the internal memory. read/write chaining the micro port of the ad6650 allows for multiple accesses while /cs is held low (/cs can be tied permanently low if the micro port is not shared with additional devices). the user can access multiple locations by pulsing the /wr or /rd line and changing the contents of the external three bit address bus. external access to the external registers of table 2 is accomplished in one of two modes using the /cs, /rd, /wr, and mode inputs. the access modes are intel non-multiplexed mode and motorola non-multiplexed mode. these modes are controlled by the mode input (mode=0 for inm, mode=1 for mnm). /cs, /rd, and /wr control the access type for each mode. programming modes the ad6650 can be programmed using several different modes. these modes include two micro-port modes, intel non-multiplexed mode and motorola non-multiplexed mode, and a serial port mode, i 2 c. the programming mode can be selected by writing the appropriate 3-bit word to the mode pins. the following table identifies which word selects the desired mode. mode [2:0] comment: 000 micro-port intel non-multiplexed mode 001 micro-port motorola non-multiplexed mode 010 reserved 011 reserved 100 i 2 c 101 reserved 110 reserved 111 reserved intel non-multiplexed mode (inm) setting the mode word bits to 000 will enable the ad6650 microprocessor in inm mode. the access type is controlled by the user with the /cs, /rd (/ds), and /wr (rw) inputs. the rdy (/dtack) signal is produced by the micro port to communicate to the user that an access has been completed. rdy (/dtack) goes low at the start of the access and is released when the internal cycle is complete. see the timing diagrams for both the read and write modes in the specifications. motorola non-multiplexed mode (mnm) setting the mode word bits to 001 will enable the ad6650 microprocessor in mnm mode. the access type is controlled by the user with the /cs, /ds (/rd), and rw (/wr) inputs. the /dtack (rdy) signal is produced by the micro port to communicate to the user that an access has been completed. /dtack (rdy) goes low when an internal access is complete and then will return high after /ds (/rd) is de-asserted. see the timing diagrams for both the read and write modes in the specifications. i 2 c control i 2 c programming is selected by setting mode =100. i 2 c is a two-line bi-directional serial interface specification developed by phillips that the ad6650 uses to program the control registers/ coefficient memory address space. it uses one data line (sda) and one clock line (scl) to transfer data between a master device and a slave device. the ad6650 can only act as an i 2 c slave, so a master device is always needed to program it in i 2 c mode. i 2 c data transfers or the ad6650 comply with the standard-mode transfer, up to 100 khz. an i 2 c bus can be multi-master and/or multi- slave relying on the wired-and function of the devices connected to it to indicate that the bus is free. to comply with this, the i 2 c pins on the ad6650 are open-drain
preliminary technical data ad6650 rev. prj 0 2/27/2003 24 outputs, meaning that they can drive a logic low, but not a logic high. the pins tri-state to indicate a logic-high and this is pulled high on the bus by external pull-up resistors to provide a logic high to the other devices on the bus. for a single-master, single-slave configuration, a 2.2 k-ohm resistor should be sufficient on each of the i 2 c lines. stable data is transferred on sda when scl is high, meaning that sda can only be changed when scl is low. if sda transitions while scl is high, this indicates to the ad6650 that a new transfer is being initiated on the i 2 c bus. a start condition from the master initiates a transfer between i 2 c devices and a stop condition ends one. a start condition is signaled by transitioning the sda line from high to low while scl is high and a transition from low to high while scl is high indicates a stop condition. acknowledge (ack) is obligatory in i 2 c, so the receiver must send an acknowledge back to the transmitter after each byte is transferred. the master generates the acknowledge- related clock pulse after a given byte is transmitted and releases the sda line. the receiver must pull the sda line to a stable low before the high period of the extra clock pulse to signal receipt of the transmitted byte. i 2 c access once a start condition has been generated, the master must transmit the ad6650 ?s 1-byte device id and a read/write bit to indicate that the rest of the access to follow is intended for it (the read/write bit and the lsb of the id are xor ?ed together to create one byte). the i 2 c device id of the ad6650 is 0010 0000 or 20 (hex). next, the master must transmit the instruction byte to the ad6650 indicating the type of access to the eir. bit comment: 7 read/write 6 x 5 si[2] 4 si[1] 3 si[0] 2 a[2] 1 a[1] 0 a[0] table xx. i 2 c instruction byte each instruction byte indicates whether the eir is being written or read (r/wn), which serial instruction (si [2:0 ]) is being executed and which register (a [2:0 ]), if appropriate, is being accessed. the serial instruction is decoded according to the following table. read/write si[2:0] function 0 000 write 1 byte: a[2:0] determines eir address 0 001 write 2 bytes: acr and car 0 010 write 2 bytes: car and dr0 0 011 write 3 bytes: acr, car and dr0 0 100 write 4 bytes: acr, car, dr1 and dr0 0 101 write 5 bytes: acr, car, dr2, dr1, and dr0 0 110 write 8 bytes: all eir addresses, acr to dr0 0 111 write 3 bytes: dr2, dr1, and dr0 1 000 read 1 byte: a[2:0] determines eir address 1 001 write 2 bytes: acr and car 1 010 write 1 byte: car; then read 1 byte: dr0 1 011 write 2 bytes: acr then car; then read 1 byte: dr0 1 100 write 2 bytes: acr then car; then read 2 bytes: dr0 then dr1 1 101 write 2 bytes: acr then car; then read 3 bytes: dr0, dr1, then dr2 1 110 read 8 bytes: all eir addresses dr0 to acr 1 111 read 3 bytes: dr0, dr1, then dr2 table xx. i 2 c instructions after the instruction byte, the appropriate data must be written to or read from the eir. finally, a stop condition is sent to end the transfer. pin multiplexing since the programming modes of the ad6650 are all mutually exclusive, the pins used for each mode are all multiplexed together and are named after their microport function. for i 2 cmode, the scl pin is the dsn pin in microport mode and the sda pin is the dtackn pin in microport mode.
preliminary technical data ad6650 rev. prj 02/27/2003 25 ad6650 mem ory map ch a ddress register bit width bit definitions 0 (hex) clock divider control 0: clock_div 1: divide by 2 0: no divide 1 pll register 0 22 2 pll register 1 22 3 pll register 2 22 4 pll register 3 22 5 clamp control 1: disable b 0: disable a 6 aux dac a 8 aux_daca 7 aux dac b 8 aux_dacb 8 aux dac control 8 7-5: fs current adjust b 4: enable dac b 3-1: fs current adjust a 0: enable dac a 9 adc dither control 2 1: high dither power 0: enable dither a dc correction bw 16 15-0: correction bw b dc correction control 7 6: multiply by .75 5-2: scalar 1: pn_en 0: enable c agc control 0 4 3: force vga gain 2: fd_enable 1: fa_enable 0: slow loop enable d agc control 1 9 8-0: vga_gain e agc control 2 16 15-8 hysterisis 7-0: requested level f agc control 3 11 10-8: loop gain-exp 7-0: loop gain-mant 10 agc control 4 12 12-10: fd_step-1 9-8: fa_thresh 7-4: fa_count 3-0: fa_step-1 11 agc control 5 16 15-8: spb peak detect period 7-0: s peak detect period 12 agc control 6 12 11-0: fd_s threshold 13 agc control 7 12 11-0: fd_spb threshold 14 start hold-off counter 16 start hold-off counter 15 cic4 decimation 5 m cic4 -1 16 cic4 scale 4 cic4_scale 17 iir control register 1 sync_mask 18 rcf decimation register 3 m rcf -1 19 rcf decimation phase 3 p rcf 1a rcf coefficient offset 6 co rcf 1b rcf taps 6 n taps -1 1c rcf scale register 2 1-0: scale 1d bist for a-i 24 bist-i/data_i 1e bist for a-q 24 bist-q/data_q 1f bist for b-i 24 bist-i/data_i
rev. prj 02/27/2003 26 preliminary technical data ad6650 20 bist for b-q 24 bist-q/data_q 21 serial control register 9 8: rcf data to bist 7: use sdo1 for b data 6-5: i_sdfs control 11: high for sdo0 valid 10: ai,aq,bi,bq pulses 01: ai,bi pulses 00: ai pulse 4: sowl 1: 24-bit words 0: 16-bit words 3: sbm 2-0: sdiv[2:0] 23-3f reserved 40-6f coefficient memory 48x20 bit ram 70-ff reserved
rev. prj 02/27/2003 27 preliminary technical data ad6650 recommended applications circuit
rev. prj 02/27/2003 28 preliminary technical data ad6650 outline dimensions dimensions shown in mm 121-pin pbga

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