filterless wideband fm if detector s1a0429a 1 introduction the s1a0429a is a monolithic integrated circuit designed for filterless and coilless fm if detector used in the cordless telephone. it includes the external 2nd if ceramic filter and the external discriminator in itself and that realized to be able to reduce the external parts extremely. features operating voltage range: 2.0 to 6.0v typical supply current: 6.3ma at 3v filterless & coilless fm if detector ? excellent demodulation characteristics ? intermediate frequency is 76khz ? include the if band pass filter (active rc filter) ? include the phase shifter (for discriminator) ? dual feedback if detect system (for the image rejection of mixer) ? the only function to be tuned is the resonant frequency of the oscillator ? minimum number of external parts required ordering information device package operating temperature S1A0429A01-s0ba 16 ? sop ? 225 ? 10 c to +70 c 16 ? sop ? 225
s1a0429a filterless wideband fm if detector 2 block diagram pin configuration 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 demodulator path control audio filter dem o tmc gnd vcc osc decpl iflt4 iflt3 rssi iflt2 iflt1 rfin+ rfin- af o aflt2 aflt1 mixer bpf limiter vco 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 s1a0429a demo tmc gnd vcc osc decpl iflt4 iflt3 aflt1 aflt2 afo rfin- rfin+ iflt1 iflt2 rssi
filterless wideband fm if detector s1a0429a 3 pin description absolute maximum ratings pin no. symbol description 1dem o demodulator output terminal, low pass filtering with the external capacitor 2 tmc this terminal stabilizes the control of audio signal path with the external capacitor 3 gnd ground 4 vcc supply voltage 5 osc local oscillator terminal the external local signal injection is possible as this terminal connects resister to vcc 6 decpl internal if amp (limiter) de-coupling terminal for dc bias 7 iflt4 if band pass filter terminal for high cut-off frequency 8 iflt3 if band pass filter terminal for low cut-off frequency 9 rssi received signal strength indicator 10 iflt2 if band pass filter terminal for high cut-off frequency 11 iflt1 if band pass filter terminal for low cut-off frequency 12 rfin+ balanced input terminal of mixer 13 rfin- balanced input terminal of mixer 14 af o recovered audio output terminal 15 aflt2 audio signal band pass filter terminal for high cut-off frequency 16 aflt1 audio signal band pass filter terminal for low cut-off frequency characteristics symbol value unit maximum supply voltage vcc 7 v operating temperature t opr ? 10 to +70 c storage temperature t stg ? 55 to +150 c
s1a0429a filterless wideband fm if detector 4 electrical characteristics (vcc = 3v, fc = 98mhz, f dev = 22.5khz, f mod = 1khz, ta = 25 c, vrfin = 150 vrms, unless otherwise specified) test circuit characteristics symbol test conditions min. typ. max. unit current consumption icc ?? 6.3 8.0 ma input for -3db limiting v lim afo = -3db 0db ref = 150 vrms rfin ? 5.0 13 vrms s/n ratio s/n ? 45 60 ? db detector output distortion thd det ?? 0.7 ? % recovered audio output v o(ra) ?? 90 ? mvrms am rejection ratio amrr am modulation = 30% 40 50 ? db 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 s1a0429a r2 10k c1 10n c2 100n gnd cv 2-6p c5 56p l5 2.7 f c6 100n c7 1.5n c8 820p vcc r9 8.2k c9 100n rssi c10 4.7n c12 220p rfin (98mhz) c13 220p c15 3.3n c16 100n gnd af output
filterless wideband fm if detector s1a0429a 5 application circuit 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 s1a0429a 10k 6.8n 10n gnd 56p vcc 100n 1.5n 560p vcc 100k 0.1 rssi 4.7n 560p rfin (10.7mhz) 220p 3.3n 0.1u gnd af output shin woo ? s coil 7bs-c4037 tel: 832-0343-74-5040 330
s1a0429a filterless wideband fm if detector 6 external parts description (see figure 3) c1 eliminates if harmonics at the output of the demodulator. c2 stabilizes on/off switching of audio signal path. the function of path control block can controlled by audio on/off signal path from demodulator to audio filter if r2 is connected to pin2, audio signal path is always on state. c5, l5, cv determines the frequency of the local oscillator. oscillated level can be suppressed with shunt resistor. the values of c5, l5 and cv depend on the required tunning range. decouples the dc feedback of limiter. c6 decouples the dc feedback of limiter. c7, c8, c10 determine the center frequency and bandwidth of active if bandpass filter. this bpf determines selectivity characteristics and demodulated output distortion characteristics. c7, c10 determines the high cut-off frequency (f hp ). c8 determines the low cut-off frequency (f lp ). c9 eliminates if harmonics at the rssi output. r9 determines rssi slope which is inversely proportional to rfin(dbm), adjust the slope and level of rssi output. c15, c16 determines the cut-off frequency of audio band pass filter c15 determines the high cut-off frequency (f hp ). c16 determines the low cut-off frequency (f lp ). f lp 1 1 c i 10 c 10 2 r i 10 -------------------------------------- - = f hp 2 1 2 r i 7 c 7 ----------------------- = f lp 2 1 2 r i 8 c 8 ----------------------- = internal parts r i10 = 2.2k ? , c i10 = 148pf r i7 = 4.7k ? r i8 = 4.7k ? f hp 1 2 r i 15 c 15 ----------------------------- = f lp 1 2 r i 16 c 16 ----------------------------- = internal parts r i15 = 12.3k ? r i16 = 14k ?
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