AM radio / FM IF stereo system IC

Transcription

1 radio / IF stereo system IC BAF BAF The BAF is a tuner system IC for electronic tuning for radios, IF, and MPX. It has been developed for HiFi component applications. The MPX VCO circuit requires no adjustment, which will enable a reduction in the number of production line processes. In particular, the laser lock technique used in the VCO means that no external adjustment is required.!applications Synthesized tuner for HiFi components.!features ) Built-in monaural radio, IF amplifier/detector, and stereo demodulator. ) DTS (both SD and IF count) compatible. ) Built-in reference voltage power supply provides good shortwave band frequency stability. ) Good stability. ) The MPX VCO uses laser locking making adjustment and external components unnecessary. ) Built-in forced monaural operation function for MPX (VCO stops, and LED goes off). ) Low cutoff of audio is possible to improve fidelity. ) MPX VCO stops in mode. ) Audio muting is possible when an IF request is made.!block diagram Vreg OSC MIX IF SD AGC / SW / PD IF Vcc SD GND LED DRIVER DECODER COMP VCO

2 BAF!Absolute maximum ratings Parameter Symbol Limits Unit Power supply voltage VCC. V Power dissipation Pd mw Operating temperature Topr + C Storage temperature Tstg + C Reduced by.mw for each increase in Ta of C over C.!Recommended operating conditions (Ta= C) Parameter Symbol Min. Typ. Max. Unit Power supply voltage VCC... V!Input and output circuits Pin No. Function Internal circuit Quiescent voltage (V) VCC Vreg IF amplifier input Connect to an ceramic filter. Ω.. GND VCC.. tuning ON level adjustment Connect a resistor from this pin to GND. to set the required ON level for the tuning indicator. kω GND discriminator.. Connect to the discriminator coil. pf Tuning indicator Connect to a tuning indicator / display device (eg. LED) Stereo indicator Connect to a stereo indicator display device (eg. LED)

3 BAF Pin No. Function Internal circuit IF request MUTE IF OUT Output the IF signal to pin excess kω of.v. kω Stops the IF signal at equal to or less than.v. MUTE Apply to muting excess of.v. Off the muting at equal to or less than.v. Quiescent pin voltage (V) IF output.. Output for the IF signal. R-channel output.. L-channel output.. kω / PLL filter Connect to a lag/lead filter. Vreg /. / band switch band when connected to GND. kω Forced monaural Forced monaural operation connecting to get a resistor to mediate. (Recommended value : kω to ground.) Vreg kω MONO.. Pilot filter Connect to a capacitor.

4 BAF Pin No. Function Internal circuit Quiescent pin voltage (V) MPX input Input the detector output. Vreg kω kω.. MPX input Input the detector output after low cut... / detector output Connect to the following stage MPX and low pass filter. kω.. AGC Connect to a capacitor. kω IF input.. Connect to an ceramic filter. kω mixer output Vreg.. Connect to primary side of IFT. kω antenna.. Connect to antenna.

5 BAF Pin No. Function Internal circuit Quiescent pin voltage (V) detector bandwidth adjustment Connect a resistor from this pin to the.. reference voltage supply to set the required detector bandwidth..kω Reference voltage supply Connected to a capacitor... local oscillator Vreg.. Connect to the OSC circuit. local oscillator output.. OSC output. Ω!Electrical characteristics (Unless otherwise specified, Ta= C and VCC=V) IF MPX signal source : fin=.mhz, modulation khz, khzdev (%) khz.khzdev (%) : fin=khz, modulation khz % Parameter Symbol Min. Typ. Max. Unit Conditions Quiescent current Quiescent current < IF MPX> Detector output voltage db limiting sensitivity Signal-to-noise ratio Channel balance suppression ratio Channel separation Total harmonic distortion Station detector sensitivity Station detector bandwidth IF OUT output voltage <> Detector output voltage Usable sensitivity Signal-to-noise ratio Total harmonic distortion Station detector sensitivity IF OUT output voltage Local buffer output voltage IQ () ma IQ () ma No input No input VO mvrms VIN=dBµV,mono L.S dbµv mono S / N db VIN=dBµV, mono C.B + db VIN=dBµV, mono R db : V IN=dBµV, mod=%, Hz SEP db VIN=dBµV, main THD.. % VIN=dBµV, main SDS dbµv Input for pin current ma SDSW khz VIN=dBµV, mono VIF mvp-p IF request ON VO mvrms VIN=dBµV Q.S dbµv Input for S / N = db S / N db VIN=dBµV THD.. % VIN=dBµV SDS dbµv Input for pin current ma VIF mvp-p IF request ON VOBuff mvrms

6 BAF!Test circuit p L OSC OUT SG. STEREO T k p. Vreg. p MONO k STEREO SG OSC MIX Vreg SD MPX LED MUTE REQ. Vcc GND STEREO SG SG SG SG. k.k TUN. ST. IFREQ OFF MUTE.....k. +B IF OUT R-ch L-ch. L : OSC T : IFT CD : DISCRIMINATOR COIL Sumida Toko Toko Sumida Toko -JPS- ABRS-X CA- -JPS- AACS-N Units : R [Ω] C [µf] Fig.

7 BAF!Application example BAF OSC Vreg OUT BW Adj IN MIXOUT IFIN AGC MPX MPX SD OSC OUT IN IN / MONO BAF BPF IN VDD SD Adj GND TUN MUTE / ST IF REQ IF OUT Rch Lch PD / Vcc (V) Lch OUT GND PD PD VDD IN IN P P P Rch OUT Vcc (+V) BUF XOUT XIN CE DA CL TUN SD IFIN P CE µ-com DA CL TUNING TO LED etc. STEREO Fig.!Electrical characteristic curves Vo, R, SEP (db) S+D+N R R L Vcc=V, SEP fin=.mhz, L R fm=khz f=±.khzdev, pilot=±.khzdev N Ta= C, D+N (%) R MOD=%, fm=hz D+N (%) INPUT VOLTAGE : VIN (dbµ) Fig. input / output characteristics Vo (mvrms) dbl, S, TUNED ON (dbµ) SEP (db) R L L R VO TUNED ON db L.S. fin=.mhz, VIN=dBµ, f=±.khzdev. (pilot=±.khzdev) fin=khz, Ta= C, RSD=kΩ D+N (%) D+N (%) POWER SUPPLY VOLTAGE : VCC (V) Fig. characteristics vs. power suppy voltage

8 BAF BAND WIDTH : fin (MHz) RBW=kΩ, VIN=dBµ Ta= C CHANNEL SEPARATION : SEP (db) Vcc=V fin=.mhz VIN=dBµ f=±.khzdev pilot=±.khzdev Ta= C THD SEP R L L R MAIN k k k k k R L SUB MONO POWER SUPPLY VOLTAGE : Vcc (V) FREQUENCY : fm (Hz) Fig. bandwidth vs. power supply voltage Fig. Channel separation and THD vs. frequency OUTPUT VOLTAGE : VO (db) S / N=dB S+D+N VAGC VOUT=V, N. fin=khz, fm=khz D+N (%) MOD=%, Ta= C D+N (%) LED ON INPUT VOLTAGE : VIN (dbµ) Fig. input / output characteristics.. VAGC (V) Q.S., TUNED ON : (dbµ) OUTPUT VOLTAGE : Vo (mvrms) fin=khz, VIN=dBµ, MOD=% fm=khz, Ta= C Vo TUNED ON Q.S. D+N (%) D+N (%) POWER SUPPLY VOLTAGE : VCC (V) Fig. characteristics vs. power suppy voltage!external dimensions (Units : mm) ECTOR OUTPUT VOLTAGE : VO (dbm) VCC=V fin=mhz VIN=dBµ MOD=% Ta= C D+N (%) VO D+N (%) k k k k k. ±.. ±.. ±... ±... ±..Min.. ±.. FREQUENCY : fm (Hz) Fig. detector output and THD vs. frequency SOP