BA7796FS

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 recorders and tape decks Video cassette •Featuresinput switching systems built-in (LINE1, 1) Three LINE2, and TUNER). 2) Built-in coil equivalent circuit for recording equalization. 3) 4) 5) 6) 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 Power supply voltage Power dissipation Operating temperature Storage temperature Symbol VCC Pd Topr Tstg Limits 13 800∗ – 10 ~ + 65 – 55 ~ + 125 Unit V mW °C °C ∗ 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 VCC Min. 7.5 Typ. — Max. 12.5 Unit V 1 Video ICs BA7796FS •Block diagram PB IN 1 REC 24 HEAD GND LP + EP HEAD EQ SW 2 23 PB PB NFB REC HEAD SW 3 REC SP 22 PB EQ SW REC OUT 4 PB 21 PB OUT REC AMP REC L2 5 EQ 0dB REC L1 6 20 PB LINE IN ALC + 28dB 19 ALC FILTER EQ CTRL 7 LINE ATT – 8dB 18 TUNER IN VCC 8 17 INPUT SW CTRL RIPPLE FILTER 9 ATT – 8dB 16 LINE IN1 REC / EE CTRL 10 MUTE 15 PB / EE CTRL BUFF LINE OUT 11 ATT – 8dB 14 LINE IN2 GND 12 13 MUTE CTRL Units: R [Ω] C [F] 2 Video ICs BA7796FS •Pin descriptions Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Pin name PB IN HEAD EQ SW REC HEAD SW REC OUT REC L 2 REC L 1 EQ CTRL VCC RIPPLE FILTER REC / EE CTRL LINE OUT GND MUTE CTRL LINE IN2 PB / EE CTRL LINE IN1 Function Playback amplifier input / playback head switch Head resonance capacitor switch High-withstanding voltage recording head switch Recording amplifier output Recording EQ switch Recording EQ pin EQ control VCC Ripple filter REC / EE control Line amplifier output GND Mute control Line input 2 PB / EE control Line input 1 Pin voltage 2.0V 0.0V 0.0V 5.7V 5.7V 5.7V — 12.0V 12.0V — 5.7V 0.0V — 5.6V — 5.6V — 5.6V PB: 0.0V PB: not fixed 5.6V 2.0V 2.0V 2.0V 0.0V I / O circuit REC: 120kΩ REC: 11Ω 220kΩ / 20Ω (ON) REC: 11Ω (ON) REC: OPEN EF (P - P) 19Ω (ON) / OPEN B (NPN) See input / output circuit — 10kΩ (VCC) See input / output circuit EF (P - P) — See input / output circuit 120kΩ See input / output circuit 120kΩ See input / output circuit 120kΩ EF (NPN) ~ 100Ω 120kΩ EF (P - P) 35Ω (ON) / OPEN B (NPN) — INPUT SW CTRL Input switch control TUNER IN ALC FILTER PB LINE IN PB OUT PB EQ SW PB NFB HEAD GND Tuner input For setting the time constant for the ALC filter (attack and recovery times) Line input for playback Playback amplifier output Playback equalizer switch Playback amplifier feedback GND for playback amplifier and head switch ∗ 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 7 EQ CTRL H L 10kΩ L H REC AMP PB HEAD SW MUTE CTRL 13 PB / EE CTRL 15 MUTE CTRL 13 56kΩ M PB / EE CTRL 15 56kΩ M INPUT SW CTRL 17 H 56kΩ L INPUT SW CTRL 17 L, M, and H in the above diagrams are 1.7V, 2.5V, and 3.3V respectively. 4 Video ICs BA7796FS CC •Electrical characteristics (unless otherwise noted, Ta = 25°C, V Parameter Quiescent current EE Quiescent current PB Quiescent current REC 〈Line amplifier〉 Voltage gain (PB input) GVCLP 27.0 19.0 — 7.3 — – 8.2 — — 28.0 20.0 0.1 10.5 – 81.5 – 7.2 0.1 – 82.0 29.0 21.0 0.3 — – 75 – 6.2 0.5 – 72 Symbol Min. IqEE IqPB IqREC 7.4 7.4 6.4 Typ. 9.8 9.8 8.4 Max. 13.0 13.0 11.2 = 12V, and f = 1kHz) Unit mA mA mA Conditions No signal input No signal input No signal input Measurement circuit Fig.1 Fig.1 Fig.1 dB dB % dBV dBV dBV % dB VO = – 8dBV VO = – 8dBV VO = – 8dBV, RL = 4.7kΩ∗ THD = 1%, RL = 4.7kΩ∗ Rg = 4.7kΩ, DIN AUDIO VIN = – 25dBV VIN = – 25dBV, RL = 4.7kΩ∗ VO = 0dBV, DIN AUDIO LINE1, LINE2, TUNER→REC OUT VO = – 8dBV VO = – 8dBV, RL = 4.7kΩ∗ THD = 1% , RL = 4.7kΩ∗ Fig.1 Fig.1 Fig.1 Fig.1 Fig.1 Fig.1 Fig.1 Fig.1 Voltage gain (LINE1, LINE2, TU inputs) GVCLT Distortion Maximum output level Output residual noise ALC level ALC distortion Mute attenuation ratio 〈Recording amplifier〉 Voltage gain Distortion Maximum output level Openloop gain 〈Playback preamplifier〉 Openloop gain Input conversion noise 〈Head switch〉 PB head switch impedance REC head switch impedance RPH RRH GVOP VNINP GVCR THDR VOmR GVOR THDLT VOmLT VNOLT VOA THDA MT 19.0 — 7.0 60 20.0 0.13 10.0 71 21.0 0.4 — — dB % dBV dB Fig.1 Fig.1 Fig.1 Fig.1 61 — 35.0 68 – 122.5 — – 114 37.0 dB dBV dB Ω Ω µA VP-P E3 = ± 55V — Rg = 680Ω, DIN AUDIO PB IN→PB OUT Fig.1 Fig.1 Fig.1 Voltage gain (stand alone, SP mode) GVCP 36.0 — — — 80 11 11 0 100 20 20 10 — — — ± 1.5V Fig.1 Fig.1 Fig.1 Fig.2 REC head switch DC withstanding voltage BVRHDC REC head switch AC withstanding voltage BVRHAC f = 70kHz, V3 ∗ Measured at BW = 0.4 to 30kHz. 5 Video ICs BA7796FS •Measurement circuits 68k PB IN 3.3µ ON : GvoPB 1 REC 24 330 22µ PB OUT 4.7µ 0.01µ 4.7k 4.7k LINE PB IN 22µ 2.2M ON : ALC OFF 0.1µ TUNER IN LINE IN1 LINE IN2 + 680 HEAD EQ SW 2 LP + EP PB 23 12k 330k REC HEAD SW REC OUT 4.7µ 3 REC SP 22 8.2k 4 15k PB 21 0.1µ 4.7k 6000p 5 1.5k 1800p 12k REC AMP EQ 0dB 20 6 ALC + 28dB 19 EQ CT RL 33µ 7 LINE ATT – 8dB 18 + + 4.7k 8 17 0.1µ INPUT SW CTRL VCC 22µ 9 ATT – 8dB 4.7k 16 REC / EE CTRL 4.7µ 10 MUTE 15 0.1µ PB / EE CTRL BUFF LINE OUT 11 ATT – 8dB 4.7k 14 4.7k 12 13 MUTE CTRL Units: R [Ω] C [F] Fig. 1 6 + + + + + Video ICs BA7796FS LP + EP 1 PB IN 2 SW3 4 REC REC OUT 3 0.1µ V ~ BVRHAC 100k 100k 1k ~ V V3 0.1µ e3 Fig. 2 REC head switch AC withstanding voltage measurement circuit •Control/ mode tablePB / EE CTRL, INPUT SW CTRL (1) REC EE CTRL, Control pins REC / EE L L L L H H H H PB / EE L L L H L L L H INPUT SW L M H — L M H — TUNER LINE2 LINE1 PB TU REC L2 REC L1 REC inhibit Mode PB HSW OFF OFF OFF OFF ON ON ON — ON ON ON ON OFF OFF OFF — Function REC HSW LINE SW TUNER LINE2 LINE1 PB TUNER LINE2 LINE1 — REC AMP OFF OFF OFF OFF ON ON ON — If REC / EE CTRL is set to“M”, the REC pause state is possible (REC head switch: open, REC amplifier: off). (2) MUTE CTRL Control pins Mode MUTE H L MUTE MUTE LINE SW OPEN CLOSE Function (3) EQ CTRL Control pins EQ L M H Mode 2 MODE SP — EP 3 MODE SP LP EP HEAD EQ OFF ON ON Function PB EQ CLOSE OPEN OPEN REC EQ CLOSE CLOSE OPEN 7 Video ICs BA7796FS 3.3µ •Application example 1 REC 24 330 22µ 0.01µ TUNER IN LINE IN1 LINE IN2 LP + EP 2 23 12k 330k 22 8.2k SP 21 REC AMP EQ 0dB 0.1µ PB 20 19 0.1µ ATT – 8dB 4 5 BIAS OSC REC + B EQ CTRL 33µ + 7 REC 3 PB 6 ALC + 28dB LINE 18 VCC 22µ 8 + 17 0.1µ INPUT SW CTRL 9 ATT – 8dB 16 MUTE REC / EE CTRL LINE OUT RL 10 15 0.1µ PB / EE CTRL BUFF 11 ATT – 8dB 14 12 13 MUTE CTRL Fig. 3 Units: R [Ω] C [F] •Operation notes (1) 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) (H) MUTE CTRL 2 sec. Min. LINE OUT (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. The mute signal must also be applied when switching PB, LINE1,LINE2 and TUNER. 8 + + + + + Video ICs BA7796FS •Electrical characteristic curves VCC = 12V VIN = – 65dBV 50 GAIN: GV (dB) + PB SP; ON. 22 8.2k 21 MAXIMUM OUTPUT VOLTAGE: Vom (dBV) 60 10 10 OUTPUT LEVEL: VOUT (dBV) 00 VCC = 12V f = 1kHz Input: LINE1 IN Output: LINE OUT 23 OUT 330k 12k 0.01µ 22µ 330 8 40 EP 30 6 SP 4 Vcc = 12V THD = 1% (BW = 0.4 ~ 30k [Hz]) ALC OFF LINE – 10 20 2 +10µ VOUT RL – 20 10 100 1k 10k 100k 1M 10M 0 100 200 500 1k 2k 5k 10k – 30 – 40 – 30 – 20 – 10 0 FREQUENCY: f (Hz) LOAD RESISTANCE: RL (Ω) INPUT LEVEL: VIN (dBV) Fig. 4 Gain vs. frequency (PB amplifier) Fig. 5 Line amplifier load drive characteristics Fig. 6 ALC input / output characteristics 50 40 GAIN: GVR (dB) VCC = 12V ALC OFF Input: LINE1 IN Output: REC OUT 6 5 4 12k 15k 6000p OUT 30 1800p EP SP 1.5k 20 10 100 1k 10k 100k FREQUENCY: f (Hz) Fig. 7 Gain vs. frequency (REC amplifier) 9 Video ICs BA7796FS •External dimensions (Units: mm) 10.0 ± 0.2 24 7.8 ± 0.3 5.4 ± 0.2 13 1 1.8 ± 0.1 12 0.11 0.8 0.36 ± 0.1 0.3Min. 0.15 SSOP - A24 10 0.15 ± 0.1