Wireless Audio Link IC

BH7F Wireless Audio Link IC BH7F The BH7F is a FM stereo transmitter IC that transmits simple configuration. The IC consists of a stereo modulator for generating stereo composite signals and a FM transmitter for broadcasting a FM signal on the air. The stereo modulator generates a composite signal which consists of the MAIN, SUB, and pilot signal from a 3kHz oscillator. The FM transmitter radiates FM wave on the air by modulating the carrier signal with a composite signal. Frequency is set for North America.!Applications Wireless speakers, Personal computer(sound board), Game machine, CD changer, Car TV, Car navigation!features ) It is possible to improve the timbre because it has the pre-emphasis circuit, limiter circuit, and the low-pass filter circuit. ) Built-in pilot-tone system FM stereo modulator circuit. 3) The transmission frequency is stable because it has a PLL system FM transmitter circuit. ) PLL controls data input in parallel (bits, ch for North America).!Absolute maximum ratings (Ta = 5 C, In measurement circuit.) Parameter Symbol Limits Unit Supply voltage Date input voltage comparator output voltage Power dissipation Storage temperature Derating :.5mW/ C for operation above Ta=5 C. VIN-D VOUT-P Pd Tstg 7.0 V 0.3~0.3 V 0.3~0.3 V mw 55~5 C Conditions Pin, Pin5,,7, Pin7!Recommended operating conditions (Ta = 5 C) Parameter Symbol Min. Typ. Max. Unit Operating supply voltage Operating temperature Audio input level Topr VIN-A.0 0.0 5 0 V C dbv Audio input frequency band fin-a 0 5k Hz time constant set up range τ PRE 55 µs Transmission frequency(00khz step) ftx 7.7 0.7.9 07.9 MHz Control terminal "H" level input voltage Control terminal "L" level input voltage VIH VIL 0. 0. V V Conditions Pin, Pin, Pin, Pin, Pin9, Pin5,,7, Pin5,,7,

BH7F!Block diagram Lch INPUT PRE-EMPHASIS TIME CONSTANT TIME CONSTANT PILOT SIGNAL ADJUST D D X'tal OSCILLATOR X'tal OSCILLATOR PLL 0 9 7 5 3 PLL Preemphasis OSC RF RF 3 5 7 9 0 9 Rch INPUT PREEMPHASIS TIME CONSTANT TIME CONSTANT FILTER COMPOSITE SIGNAL OUTPUT PLL PHASE DETECTOR OUTPUT RF OSCILLATOR RF RF OUTPUT

BH7F!Pin descriptions Pin No. Pin descriptions Equivalent circuit DC (V) Rch audio source input terminal It cuts DC with the capacitor and it inputs R-ch audio signal. 3k Lch audio source input terminal or.7k It cuts DC with the capacitor and it inputs L-ch audio signal. k, time constant terminal It connects a capacitor for the time constant of pre-emphasis. τ=.7kω C or 3,0 time constant terminal This is 5kHz. It connects a pf capacitor. 00k 00k 00k p 0 3 or Filter terminal It is a ripple filter for the reference voltage of the audio part. k k 5 Composite signal output terminal It connects to the FM modulator. 5 7 PLL phase output terminal It connects to the PLL circuit. 7 Power supply terminal

BH7F Pin No. Pin descriptions Equivalent circuit DC (V) 9 RF oscillator terminal This is the base terminal of the colpitts oscillator. It connects time constant of the oscillation. 9 5k p p 7 0k 30p 0 0 RF RF transmission output terminal It connects to the antenna through BPF..9 0 PLL power supply terminal 3, X'tal oscillator terminal It connects a crystal oscillator. k 3 M 5 Parallel data set up terminal Parallel data set up terminal D 7 Parallel data set up terminal D 5 7 or or or Parallel data set up terminal 9 Pilot signal adjust terminal 9 5k

BH7F!Electrical characteristics (Unless otherwise noted, Ta = 5 C, = 5.0V Signal source : fin = 00Hz) Parameter Symbol Min. Typ. Max. Unit Conditions Quiescent current IQ 0 ma Channel separation Sep 5 0 db Total harmonic distortion THD 0. 0.3 % Channel balance Input output gain Pilot modulation rate Sub carrier rejection ratio time constant Limiter input level cut off frequency Transmission output level "H" level input current C.B Gv MP SCR τ PRE VIN(LIM) fc() VTX IIH 0 9 0 0 5 30 3 5 99 0 0 0 0.0 db db % db µs dbv khz dbµv µa VIN=0dBV L R,R L VIN=0dBV LR VIN=0dBV LR VIN=0dBV LR VIN=0dBV,LR Pin5 VIN=0dBV LR VIN=0dBV LR Output level at db gain compression VO=3dB Pin, Open ftx=07.9mhz Pin5,,7, VIN=5V Measurement circuit Fig. Fig. Fig.3 Fig. Fig.3 Fig.3 Fig.3 Fig.3 Fig. Fig.5 Fig. Fig.7 "L" level input current IIL.0 µa Pin5,,7, VIN=0V Fig.7 "H" level output voltage "L" level output voltage VOH VOL.0 0.5 0.5.0 V V Pin7 IOUT=.0mA Pin7 IOUT=.0mA Fig. Fig. "off" level leak current IOFF 00 na Pin7 VOUT=5V Fig.9 "off" level leak current IOFF 00 na Pin7 VOUT= Fig.9

BH7F!Measurement circuits Quiescent current 0 9 7 5 3 PLL OSC RF RF 3 5 7 9 0 9 00p p 0µ D D 00p p 0.0µ 0.0µ 00µ 5V IQ A Fig.

BH7F Channel separation Channel balance 0µ 00p p 70p D D 0.0µ L-ch 0 9 7 5 3 PLL fin = 00Hz VIN = -0dBV R-ch 0µ OSC RF RF 3 5 7 9 0 00p p 0µ 0µ 0k 0.0µ 00µ 9 Stereo signal demodulator 5V L-ch V ~ V ~ R-ch Sep, C.B Fig.

BH7F Total harmonic distortion Input output gain Pilot index of modulation Sub carrier rejection ratio time constant 0µ 00p D D 0.0µ p 70p L-ch 0 9 7 5 3 PLL ~ fin=00hz VIN=0dBV R-ch 0µ 9 OSC RF RF 3 5 7 9 0 00p p 0µ 0k 0µ 0.0µ 00µ Spectrum analyzer SCR GV, MP τ PRE IHF BPF 00Hz~5kHz 5V THD, VO(MUTE) 0 Output response (db) -0-0 -30-0 - SCR -0 0 0k 0k 30k 0k k Frequency (Hz) Fig.3

BH7F Limiter input level 0µ 00p p 70p D D 0.0µ L-ch 0 9 7 5 3 PLL ~ fin=00hz R-ch 0µ 9 OSC RF RF 3 5 7 9 0 00p p 0µ 0k 0µ 0.0µ 00µ VIN (LIM) 5V Output level (dbv) db Input level (dbv) VIN(LIM) Fig.

BH7F cut off frequency 0µ p 70p D D 0.0µ L-ch 0 9 7 5 3 PLL ~ fin=00hz VIN=0dBV R-ch 0µ 9 OSC RF RF 3 5 7 9 0 p 0µ 0k 0µ 0.0µ 00µ fc () 5V Output response (db) 3dB Frequency (Hz) fc() Fig.5

BH7F Transmission output level D D 0.0µ 0 9 7 5 3 PLL 3 5 7 9 0 0µ 0k 0.0µ 00µ 9 5p FEM0C-F (SUMIDA) OSC RF RF p 000p 0k KV-7E (TOKO) VTX Spectrum analyzer Zin=Ω ftx=07.9mhz 0.07µ 5.k 00 33µ 0k 5V SDK (ROHM) 000p Fig.

BH7F H level input current L level input current 0V, 5V A IIH, IIL D D 0.0µ 0 9 7 5 3 PLL 3 5 7 9 0 0.0µ 9 OSC RF RF 00µ 5V Fig.7

BH7F H level output voltage L level output voltage D D 0.0µ 0 9 7 5 3 PLL 9 OSC RF RF 3 5 7 9 0 0.0µ VOH, VOL V VOH 00µ VOL 000p ~ SG fin=0.0mhz (VOH) fin=07.mhz (VOL) ma ma 5V Fig.

BH7F off level leak input current D D 0.0µ 0 9 7 5 3 PLL 3 5 7 9 0 0.0µ 9 OSC RF RF 00µ IOFF, IOFF A 0V, 5V 5V Fig.9

BH7F!Application circuit US BAND (.0MHz 9.MHz) 0µ 0.µ 0 9 7 5 3 PLL k µ µ 0.0µ 000p 0µ 33 RF 3 5 7 9 0 000p 30 GFWB3 (SOSHIN) 33p FEM0C-F (SUMIDA) 0k 33p 0k 330p 0k p 0k KV-7E (TOKO) 0.07µ.k 3.3k 3.3k VT 00 00µ SDK (ROHM) 00p p L-CH k µ µ R-CH 00p p µ ANT 00p 0µ 00µ Fig.0

BH7F!Circuit operation Parallel data Control data (Pin5) D (Pin) D (Pin7) (Pin) L L L L H L L L L H L L H H L L L L H L H L H L L H H L H H H L L L L H H L L H L H L H H H L H L L H H H L H H L H H H H H H H Frequency 7.7MHz 7.9MHz.MHz.3MHz.5MHz.7MHz.9MHz PLL stops. comparator terminal supports high impedance. 0.7MHz 0.9MHz 07.MHz 07.3MHz 07.5MHz 07.7MHz 07.9MHz PLL stops. comparator terminal supports high impedance.!external dimensions (Units : mm) 3.±0. 7.±0.3 5.±0..±0. 0. 0.3Min..7 0.±0. 0. 0.5±0. SOP