Video ICs Switchless REC / PB amplifier for standard audio signal processing BA7757BK The BA7757BK contains a playback equalizer amplifier, an REC / PB switch, a line amplifier, an ALC circuit with built-in detector, a recording amplifier, an analog switch for input switching, and a logic control circuit for independent switching of REC / EE, PR / EE, line mute and input. The IC is easy to interface with control systems, and features low noise during mode switching and at power on / off. The line amplifier and recording amplifire are directly connected internally, allowing construction of a high-performance audio signal processing circuit for VCRs using a minimum number of external components. •1)Features All necessary switches for audio signal processing are built-in. · MIC / LINE input selector switch. · EP / SP equalizer selector switch. · Built-in head switch on the playback side of the head for head switching for REC / PB, and a headswitch driver terminal provided on the recording side. · EE / PB and EE / REC selector switches (compatibility with after-recording mode (AFR) is possible). · Line muting switch. 2) All control functions are independent, so interfacing with the control system is simple. 3) Amplifiers required for audio recording and playback are provided on the IC. 4) Excellent S / N and distortion specifications through use of high-level ALC VR. 5) The ALC level is set using a external resistor, and variation due to temperature is extremely low. 6) Built-in ripple filter gives excellent ripple rejection. 7) Low noise generation when power is switched on and off, and during control system switching. 8) The line output can directly drive earphone. 9) Few external parts required. 10) Available in a QFP32 package, for high-density mounting. 11) Low power consumption. 1 Video ICs BA7757BK PB IN GND LINE / MIC INPUT CTRL INPUT SW OUT LINE IN MIC IN FREQ. COMPENSATION GND •Block diagram 24 23 22 21 20 19 18 17 INPUT SW EP SW 25 PB NF 26 FILTER 27 SP SW 28 VCC 29 120kΩ 16 EP SW 15 EP / SP CTRL 14 REC NFB 13 EE / REC CTRL 12 REC OUT 11 EE / PB CTRL 10 HEAD SW CTRL 9 LINE OUT PB BIAS REC Vreg PB OUT 30 LINE REC IN 31 LINE PB IN 32 – 24.4dB 39.2dB R LINE P BF BIAS 2 1 2 3 4 5 6 7 8 BIAS 1 (VCC / 2) LINE NFB N.C. BIAS 2 ALC FILTER AGC VR CTRL ALC LEVEL MUTE CTRL ALC Video ICs BA7757BK •Absolute maximum ratings (Ta = 25°C) Parameter Symbol Limits Power supply voltage VCC 8.0∗1 Power dissipation Pd 400∗2 Unit V mW Operating temperature Topr – 10 ~ + 65 °C Storage temperature Tstg – 55 ~ + 125 °C ∗1 When IC is stand alone. ∗2 Reduced by 4mW for each increase in Ta of 1°C over 25°C. •Recommended operating conditions Parameter Power supply voltage Symbol Min. Typ. Max. Unit VCC 4.0 — 6.0 V •Electrical characteristics (unless otherwise noted, Ta = 25°C, V CC Parameter = 5V, and f = 1kHz) Symbol Min. Typ. Max. Unit Quiescent current (SP mode) IqSP — 7.0 9.8 mA Conditions No signal, EE and SP mode Quiescent current (EP mode) IqEP — 8.0 11.2 mA No signal, EE and EP mode DISTNEE — 0.06 0.2 % Maximum output level VOmL 0.75 1.1 — Vrms DISTN = 1%∗1 ALC level VOA – 6.8 – 3.2 dBV VIN = – 15dBV 〈Line amplifier〉 (LINE IN ~ LINE OUT) Distortion ALC distortion DISTNA –5 LINE IN ~ LINE OUT, VIN = – 25dBV∗1 — 0.08 0.2 % VIN = – 15dBV∗1 〈Recording amplifier〉 (LINE IN ~ REC OUT) Gain Distortion Maximum output level GVR 39.1 40.8 42.5 dB VIN = – 25dBV, input attenuation conversion DISTNR — 0.06 0.2 % VIN = – 25dBV∗1 VOmR 0.85 1.2 — Vrms DISTN = 1%∗1 〈Input switch〉 (MIC IN ~ SW OUT) Gain Distortion Input resistance Maximum output level GVSW DISTNSW – 0.5 — 0 — dB VIN = – 14dBV 0.002 0.1 % VIN = – 14dBV∗1 ZINM — 75 — kΩ VOmsw 0.85 1.2 — Vrms DISTN = 1%∗1 ∗1 Measured at BW = 0.4 to 30kHz. 3 Video ICs BA7757BK •Measurement circuit 470p 62k 4.7µ 10k 1µ + 24 23 22 MIC IN LINE IN 1k 1k + + 6.2k INPUT SW OUT 21 0.47µ 20 + INPUT SW CTRL PB IN 220p 0.47µ 19 18 17 INPUT SW 25 220 16 33µ 120kΩ + 26 330k 0.01µ EP / SP CTRL 15 + 14 2.7k 33µ 12k 51k BIAS 28 1µ – 24.4dB 1µ + 31 + 32 5.6k 39.2dB R 5.6k 56k EE / PB CTRL 11 10 LINE P A VCC 10µ BF 9 + 1µ 56k REC OUT 10k 30 + 12 Vreg + + REC 29 100µ PB OUT & LINE (PB) IN EE / REC CTRL 13 5.6k VCC LINE (REC) IN ON GVOREC 4.7µ PB 27 + ON Gvope LINE OUT 1µ 10k BIAS 1 33µ 2 + + 3 NP 22µ ON RL 100Ω ALC 4 5 6 7 8 47µ N.C. 1M 22k + 10k ON ALC OFF FADE OUT / FADE IN CTRL Fig. 1 4 100 MUTE CTRL Units R: Ω C: F Video ICs BA7757BK •Application example AUDIO HEAD INPUT SW CTRL LINE IN MIC IN 1k 1k + + TP AC BIAS OSC TP 24 23 22 21 0.47µ 20 0.47µ 19 220p 18 17 INPUT SW 16 25 + 120kΩ 26 15 EP / SP CTRL PB + 14 27 33µ BIAS REC 29 12 Vreg – 24.4dB 30 11 + 10 + LINE P BF 32 BIAS 1 33µ 2 + + 3 NP N.C. 22µ EE / PB CTRL 39.2dB R 31 + VCC EE / REC CTRL 13 9 + 28 VCC LINE OUT ALC 4 5 1M + 6 7 22k 47µ FADE OUT / FADE IN CTRL Fig. 2 8 10k MUTE CTRL Units R: Ω C: F •External dimensions (Units: mm) 9.0 ± 0.3 7.0 ± 0.2 17 16 32 9 1.45 ± 0.1 0.05 1 0.8 8 0.4 ± 0.1 0.4 9.0 ± 0.3 7.0 ± 0.2 24 25 0.15 ± 0.1 0.15 QFP32 5