Video ICs VCR standard audio signal processor BA7796FS The BA7796FS is a standard audio signal processor designed for use in VCRs and tape decks. The circuit is comprised of a playback preamplifier, a line amplifier, a recording amplifier, an ALC circuit, an EQ switch, and high-voltage head switch. The IC has three input switching systems, and a built-in coil equivalent circuit for recording equalization, which eliminates the need for an external component. Applications •Video cassette recorders and tape decks •1)Features Three input switching systems built-in (LINE1, 3) 4) 5) 6) LINE2, and TUNER). 2) Built-in coil equivalent circuit for recording equalization. Two-mode EQ switch. High-performance low-noise playback amplifier. Fixed ALC level ( – 7.2dB when VCC = 12V). Phase-inverting recording amplifier. •Absolute maximum ratings (Ta = 25°C) Parameter Symbol Limits Unit VCC 13 V mW Power supply voltage Pd 800∗ Operating temperature Topr – 10 ~ + 65 °C Storage temperature Tstg – 55 ~ + 125 °C Power dissipation ∗ When mounted on a 90mm × 50mm × 1.6mm glass epoxy board. Reduced by 8.0mW for each increase in Ta of 1°C over 25°C. •Recommended operating conditions (Ta = 25°C) Parameter Power supply voltage Symbol Min. Typ. Max. Unit VCC 7.5 — 12.5 V 1 Video ICs BA7796FS 2 REC HEAD SW 3 REC OUT 4 REC L2 5 24 HEAD GND 23 PB NFB 22 PB EQ SW 21 PB OUT 20 PB LINE IN 19 ALC FILTER 18 TUNER IN 17 INPUT SW CTRL 16 LINE IN1 15 PB / EE CTRL 14 LINE IN2 13 MUTE CTRL PB HEAD EQ SW LP + EP 1 PB SP REC PB IN REC •Block diagram REC AMP EQ 0dB REC L1 6 ALC + 28dB ATT – 8dB 8 RIPPLE FILTER 9 REC / EE CTRL 10 LINE OUT 11 GND 12 ATT – 8dB MUTE VCC LINE 7 BUFF EQ CTRL ATT – 8dB Units: R [Ω] C [F] 2 Video ICs BA7796FS •Pin descriptions Pin name Function Pin voltage I / O circuit 1 PB IN Playback amplifier input / playback head switch 2.0V REC: 120kΩ REC: 11Ω 2 HEAD EQ SW Head resonance capacitor switch 0.0V 220kΩ / 20Ω (ON) 3 REC HEAD SW High-withstanding voltage recording head switch 0.0V REC: 11Ω (ON) REC: OPEN 4 REC OUT Recording amplifier output 5.7V EF (P - P) 5 REC L 2 Recording EQ switch 5.7V 19Ω (ON) / OPEN 6 REC L 1 Recording EQ pin 5.7V B (NPN) 7 EQ CTRL — See input / output circuit Pin No. EQ control 8 VCC VCC 12.0V — 9 RIPPLE FILTER Ripple filter 12.0V 10kΩ (VCC) 10 REC / EE CTRL REC / EE control 11 LINE OUT 12 GND 13 MUTE CTRL 14 LINE IN2 15 PB / EE CTRL 16 LINE IN1 17 — See input / output circuit Line amplifier output 5.7V EF (P - P) GND 0.0V — Mute control — See input / output circuit Line input 2 5.6V 120kΩ PB / EE control Line input 1 INPUT SW CTRL Input switch control — See input / output circuit 5.6V 120kΩ — See input / output circuit 5.6V 120kΩ PB: 0.0V PB: not fixed EF (NPN) ~ 100Ω Line input for playback 5.6V 120kΩ PB OUT Playback amplifier output 2.0V EF (P - P) 22 PB EQ SW Playback equalizer switch 2.0V 35Ω (ON) / OPEN 23 PB NFB Playback amplifier feedback 2.0V B (NPN) 24 HEAD GND GND for playback amplifier and head switch 0.0V — 18 TUNER IN 19 ALC FILTER For setting the time constant for the ALC filter (attack and recovery times) 20 PB LINE IN 21 Tuner input ∗ EF: emitter follower, P-P: push pull, B: base, and C: collector. All measurements made using the measurement circuit (Fig. 1) with VCC = 12V and quiescent circuit conditions. All numerical values are standardized values. 3 Video ICs BA7796FS •Input / output circuits EQ CTRL 7 REC / EE CTRL 10 REC / EE CTRL 10 56kΩ 10kΩ L 7 EQ CTRL H H L REC AMP PB / EE CTRL 15 MUTE CTRL 13 MUTE CTRL 13 PB HEAD SW 56kΩ M PB / EE CTRL 15 56kΩ M INPUT SW CTRL 17 H 56kΩ L L, M, and H in the above diagrams are 1.7V, 2.5V, and 3.3V respectively. 4 INPUT SW CTRL 17 Video ICs BA7796FS •Electrical characteristics (unless otherwise noted, Ta = 25°C, V CC Parameter Symbol Min. = 12V, and f = 1kHz) Typ. Max. Unit Conditions Measurement circuit Quiescent current EE IqEE 7.4 9.8 13.0 mA No signal input Fig.1 Quiescent current PB IqPB 7.4 9.8 13.0 mA No signal input Fig.1 Quiescent current REC IqREC 6.4 8.4 11.2 mA No signal input Fig.1 GVCLP 27.0 28.0 29.0 dB VO = – 8dBV Fig.1 Voltage gain (LINE1, LINE2, TU inputs) GVCLT 19.0 20.0 21.0 dB VO = – 8dBV Fig.1 — 0.1 0.3 % VO = – 8dBV, RL = 4.7kΩ∗ Fig.1 THD = 1%, RL = 4.7kΩ∗ Fig.1 〈Line amplifier〉 Voltage gain (PB input) Distortion THDLT Maximum output level VOmLT Output residual noise 7.3 10.5 VNOLT — – 81.5 – 75 dBV Rg = 4.7kΩ, DIN AUDIO Fig.1 VOA – 8.2 – 7.2 – 6.2 dBV VIN = – 25dBV Fig.1 THDA — 0.1 0.5 % VIN = – 25dBV, RL = 4.7kΩ∗ Fig.1 MT — – 82.0 – 72 dB VO = 0dBV, DIN AUDIO Fig.1 Voltage gain GVCR 19.0 20.0 21.0 dB LINE1, LINE2, TUNER→REC OUT Fig.1 Distortion THDR — 0.13 0.4 % VO = – 8dBV Fig.1 VO = – 8dBV, RL = 4.7kΩ∗ Fig.1 THD = 1% , RL = 4.7kΩ∗ Fig.1 ALC level ALC distortion Mute attenuation ratio — dBV 〈Recording amplifier〉 Maximum output level Openloop gain VOmR 7.0 10.0 — dBV GVOR 60 71 — dB Openloop gain GVOP 61 68 — dB Input conversion noise VNINP — 〈Playback preamplifier〉 Voltage gain (stand alone, SP mode) GVCP – 122.5 – 114 dBV 35.0 36.0 37.0 dB — Fig.1 Rg = 680Ω, DIN AUDIO Fig.1 PB IN→PB OUT Fig.1 〈Head switch〉 ∗ PB head switch impedance RPH — 11 20 Ω — Fig.1 REC head switch impedance RRH — 11 20 Ω — Fig.1 REC head switch DC withstanding voltage BVRHDC — 0 10 µA E3 = ± 55V Fig.1 REC head switch AC withstanding voltage BVRHAC 80 100 — VP-P f = 70kHz, V3 ⬉ ± 1.5V Fig.2 Measured at BW = 0.4 to 30kHz. 5 Video ICs BA7796FS •Measurement circuits 3.3µ 68k ON : GvoPB REC 680 24 22µ + 1 330 PB IN + 1800p 12k + 0.01µ LINE PB IN TUNER IN 18 4.7k 10 0.1µ 22µ + ATT – 8dB 9 MUTE BUFF ATT – 8dB 4.7k LINE IN1 16 PB / EE CTRL 15 4.7µ + 11 INPUT SW CTRL 17 0.1µ + 33µ ATT – 8dB ON : ALC OFF 0.1µ LINE 22µ 2.2M 19 ALC 8 LINE OUT 4.7k 20 7 REC / EE CTRL 4.7k 0.1µ REC AMP EQ 0dB + 28dB VCC PB OUT + SP PB 15k 6000p 21 6 EQ CT RL 330k PB REC 4.7µ + 4.7k 22 4 5 1.5k 12k 3 REC OUT 8.2k REC HEAD SW 23 4.7µ 2 LP + EP HEAD EQ SW 4.7k LINE IN2 14 4.7k 12 13 Units: R [Ω] C [F] Fig. 1 6 MUTE CTRL BA7796FS 2 3 SW3 PB IN REC 1 LP + EP Video ICs 4 REC OUT 0.1µ V ~ BVRHAC 100k 100k 1k ~ V e3 0.1µ V3 Fig. 2 REC head switch AC withstanding voltage measurement circuit mode table •(1)Control REC / EE CTRL, PB / EE CTRL, INPUT SW CTRL Control pins Function Mode REC / EE PB / EE L L L L L M L L H PB HSW REC HSW LINE SW REC AMP TUNER OFF ON TUNER OFF LINE2 OFF ON LINE2 OFF LINE1 OFF ON LINE1 OFF INPUT SW L H — PB OFF ON PB OFF H L L TU REC ON OFF TUNER ON H L M L2 REC ON OFF LINE2 ON H L H L1 REC ON OFF LINE1 ON H H — inhibit — — — — If REC / EE CTRL is set to“M”, the REC pause state is possible (REC head switch: open, REC amplifier: off). (3) EQ CTRL (2) MUTE CTRL Control pins Function Control pins Mode Function LINE SW EQ 2 MODE 3 MODE HEAD EQ PB EQ REC EQ Mode MUTE H MUTE OPEN L SP SP OFF CLOSE CLOSE L MUTE CLOSE M — LP ON OPEN CLOSE H EP EP ON OPEN OPEN 7 Video ICs BA7796FS 24 + BIAS OSC REC AMP EQ 0dB + 20 6 19 ALC LINE 7 – 8dB 10 11 0.1µ PB / EE CTRL 0.1µ MUTE ATT – 8dB 12 14 13 Fig. 3 notes •(1)Operation Mute signal Apply the mute signal shown below at power on and off. If the muting time is short, a “pop” sound will be audible, particularly when the power is switched on. Vcc (H) LINE IN1 16 15 BUFF + RL ATT 9 LINE OUT INPUT SW CTRL 17 22µ + REC / EE CTRL 2 sec. Min. TUNER IN 18 33µ + 8 VCC (H) ATT – 8dB 0.1µ + 28dB REC + B EQ CTRL 0.01µ 8.2k 0.1µ 21 PB + 4 5 MUTE CTRL LINE OUT The mute signal must also be applied when switching PB, LINE1,LINE2 and TUNER. 8 12k 330k PB LP + EP 22 SP 3 23 REC 2 22µ 1 330 + REC 3.3µ •Application example LINE IN2 MUTE CTRL Units: R [Ω] C [F] (2) Recording control Do not switch the PB and REC modes on together. This will cause erroneous operation. (3) Line output The line output can drive a load resistance of up to 2kΩ. Some types of load can result in local oscillation (eg. large capacitive loads that draw large current), so caution is required. In particular, when there is a possibility that the line output will be connected to a shielded cable, or line cable, connect a resistor of about 1kΩ in series with the output so that the capacitive load is not directly coupled to the IC output terminal. Video ICs BA7796FS VCC = 12V VIN = – 65dBV PB 23 GAIN: GV (dB) 50 SP; ON. 22 8.2k 21 OUT 330k 12k + 40 EP 30 0.01µ 22µ 330 SP 20 10 100 1k 10k 100k 1M 10M Fig. 4 Gain vs. frequency (PB amplifier) 40 8 6 Vcc = 12V THD = 1% (BW = 0.4 ~ 30k [Hz]) ALC OFF 4 LINE 2 +10µ VOUT RL 0 100 200 500 1k 2k 5k 10k Fig. 5 Line amplifier load drive characteristics Input: LINE1 IN Output: LINE OUT 00 – 10 – 20 – 30 – 40 – 30 – 20 – 10 0 INPUT LEVEL: VIN (dBV) Fig. 6 ALC input / output characteristics VCC = 12V ALC OFF Input: LINE1 IN Output: REC OUT 6 5 12k GAIN: GVR (dB) VCC = 12V f = 1kHz LOAD RESISTANCE: RL (Ω) FREQUENCY: f (Hz) 50 10 10 OUTPUT LEVEL: VOUT (dBV) 60 MAXIMUM OUTPUT VOLTAGE: Vom (dBV) •Electrical characteristic curves 4 15k 6000p 30 1800p 1.5k OUT EP SP 20 10 100 1k 10k 100k FREQUENCY: f (Hz) Fig. 7 Gain vs. frequency (REC amplifier) 9 Video ICs BA7796FS •External dimensions (Units: mm) 1 12 5.4 ± 0.2 13 0.8 0.36 ± 0.1 0.15 ± 0.1 1.8 ± 0.1 0.11 7.8 ± 0.3 10.0 ± 0.2 24 0.3Min. 0.15 SSOP - A24 10