Video ICs VCR standard audio signal processor BA7797F The BA7797F is 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 and high-voltage head switch. The IC has 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 Two input switching systems built-in (LINE and TUNER). 2) Built-in coil equivalent circuit for recording equalization. 3) High-performance low-noise playback amplifier. 4) ALC level can be adjusted by connection of an external resistor. 5) Compatible with single-mode EQ making it ideally suited to widely-used decks. REC HEAD SW 2 REC OUT 3 REC AMP 4 VCC 5 GND 17 PB NFB 16 PB OUT 15 PB LINE IN 14 ALC FILTER 13 TUNER IN 12 PB / TU / LINE CTRL 11 LINE IN 10 MUTE CTRL + 28dB EQ REC L 18 PB 1 REC PB IN REC •Block diagram LINE 0dB ALC REC / EE CTRL 7 LINE OUT 8 ALC LEVEL ADJ 9 ATT – 8dB MUTE 6 BUFF RIPPLE FILTER ATT – 8dB 1 Video ICs BA7797F •Absolute maximum ratings (Ta = 25°C) Parameter Symbol Limits Unit Power supply voltage VCC 13 V Power dissipation Pd 550∗ mW Operating temperature Topr – 10 ~ + 65 °C Storage temperature Tstg – 55 ~ + 125 °C ∗ When mounted on a 50mm × 50mm × 1.6mm glass epoxy board. Reduced by 5.5mW for each increase in Ta of 1°C over 25°C. •Recommended operating conditions (Ta = 25°C) Parameter Symbol Min. Typ. Max. Unit VCC 7.5 — 12.5 V Power supply voltage •Pin descriptions (V CC Pin No. = 10V) Pin name Function Pin voltage 1 PB IN Playback amplifier input / playback head switch 2.0V 2 REC HEAD SW High-withstanding voltage recording head switch 0.0V REC: 17Ω (ON) REC: OPEN 3 REC OUT Recording amplifier output 4.7V EF (P-P) 4 REC L Recording EQ switch 4.7V B (NPN) 5 VCC VCC 10.0V — 6 RIPPLE FILTER Ripple filter 10.0V 10kΩ (VCC) 7 REC / EE CTRL REC / EE control 8 LINE OUT Line amplifier output 4.7V EF (P-P) ALC level adjustment 4.1V See Fig. 4 9 ALC LEVEL ADJ 10 MUTE CTRL 11 LINE IN 12 PB / TU / LINE CTRL 13 TUNER IN Mute control Line input PB / TU / LINE control Tuner input — — 4.7V — 4.7V PB: 0.0V PB: Not fixed See input / output circuit See input / output circuit 120kΩ See input / output circuit 120kΩ 14 ALC FILTER For setting the time constant for the ALC filter (attack and recovery times) 15 PB LINE IN Line input for playback 4.7V 120kΩ 16 PB OUT Playback amplifier output 2.0V EF (P-P) 17 PB NFB Playback amplifier feedback 2.0V B (NPN) 18 GND GND 0.0V ∗ EF: emitter follower, P-P: push pull, B: base, and C: collector. All measurements made using the measurement circuit (Fig.1) with VCC = 10V and quiescent circuit conditions. All numerical values are standardized values. 2 I / O circuit REC: 120kΩ REC: 11Ω EF (NPN) ~ 100Ω — Video ICs BA7797F •Input / output circuits REC / EE CTRL 7 MUTE CTRL 10 REC / EE CTRL 7 MUTE CTRL 10 56kΩ H 56kΩ M L REC AMP PB HEAD SW PB / TU / LINE CTRL 12 H L PB / TU / LINE CTRL 56kΩ 12 3 Video ICs BA7797F •Electrical characteristics (unless otherwise noted, Ta = 25°C, V CC Parameter = 10V, and f = 1kHz) Conditions Measurement circuit Symbol Min. Typ. Max. Unit Quiescent current EE IqEE 6.4 8.5 11.3 mA No signal Fig.1 Quiescent current PB IqPB 6.4 8.5 11.3 mA No signal Fig.1 Quiescent current REC IqREC 5.2 6.9 9.2 mA No signal Fig.1 〈Line amplifier〉 Voltage gain (PB input) 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 Distortion THDLT — 0.1 0.3 % VO = – 8dBV, RL = 4.7kΩ∗ Fig.1 Maximum output level VOMLT 5.9 8.4 — dBV THD = 1%, RL = 4.7kΩ∗ Fig.1 Output residual noise VNOLT — – 81.5 – 75 dBV Rg = 4.7kΩ, DIN AUDIO Fig.1 – 9.0 – 8.0 – 7.0 dBV VIN = – 25dBV, 9pin: OPEN 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 LINE IN, TUNER IN→REC OUT Fig.1 Distortion THDR — 0.13 0.4 % VO = – 8dBV Fig.1 Maximum output level VOMR 5.7 8.2 — dBV VO = – 8dBV, RL = 4.7kΩ∗ Fig.1 Openloop gain GVOR 60 71 — dB THD = 1%, RL = 4.7kΩ∗ Fig.1 Openloop gain GVOP 61 68 — Input conversion noise VNINP — Voltage gain (stand alone) GVCP 35.0 36.0 37.0 dB PB head switch impedance RPH — 11 20 Ω Fig.1 REC head switch impedance RRH — 17 25 Ω Fig.1 — 0 10 µA E2 = ± 55V Fig.1 80 100 — VP-P f = 70kHz, V2 ⬉ ± 1.5V Fig.2 ALC level ALC distortion Mute attenuation ratio VOA 〈Recording amplifier〉 Playback preamplifier – 122.5 – 114 Fig.1 dB dBV Rg = 680Ω, DIN AUDIO Fig.1 PB IN→PB OUT Fig.1 〈Head switch〉 REC head switch DC withstanding voltage BVRHDC REC head switch AC withstanding voltage BVRHAC ∗ Measured at BW = 400Hz to 30kHz. 4 Video ICs BA7797F 3.3µ •Measurement circuits ON: Gvo PB + 28dB LINE 22µ 0.01µ 4.7µ 15 4.7k PB LINE IN 47k 5 22µ + 8 4.7k 13 12 ATT – 8dB TUNER IN 47k PB / TU / LINE CTRL 4.7k 0.1µ BUFF 4.7µ 7 MUTE + REC / EE CTRL ATT – 8dB 0.1µ ALC 6 ON: ALC OFF 2.2M 14 22µ + 33µ 4.7k 0.1µ 12k REC AMP EQ 0dB + 1800p 4 VCC LINE OUT PB OUT 16 + 6000p 3 330k 12k PB 4.7µ + 4.7k + 17 REC 2 1.5k 18 330 + 1 680 REC HEAD SW REC OUT REC 68k PB IN 11 LINE IN 47k 4.7k 9 MUTE CTRL 10 Units: R [Ω] C [F] Fig.1 1 SW2 3 REC 2 PB IN REC OUT 0.1µ V ~ BVRHAC 100k 100k 1k e2 V2 V 0.1µ REC head switch AC withstanding voltage measurement circuit Fig. 2 5 Video ICs BA7797F •Control mode table (1) REC / EE control, PB / TU / LINE control Control pins Function Mode REC / EE PB / TU / LINE PB HSW REC HSW LINE SW L L LINE OFF ON LINE REC AMP OFF L M TUNER OFF ON TUNER OFF OFF L H PB OFF ON PB H L LINE REC ON OFF LINE ON H M TU REC ON OFF TUNER 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). (2) Mute control Control pins Function Mode MUTE LINE SW H MUTE OPEN L MUTE CLOSE 330k LINE 15 22µ 12k 8.2k + 28dB EQ CTRL + 4 16 REC AMP EQ 0dB 0.1µ + 3 EQ CTRL 0.01µ 17 PB 2 18 330 1 REC 3.3µ + BIAS OSC + REC + B REC •Application example 5 7 + 8 MUTE ATT – 8dB 9 11 10 TUNER IN PB / TU / LINE CTRL 12 BUFF LINE OUT 13 0.1µ ATT – 8dB 6 0.1µ + REC / EE CTRL RL 14 ALC 22µ + 33µ VCC LINE IN MUTE CTRL ALC LEVEL ADJ Units: R [Ω] C [F] Fig.3 6 Video ICs BA7797F notes •(1)Operation ALC level Set the ALC level in the range – 8dBV to 0dBV by connecting a resistor between pin 9 and GND. VOA = = 1 2 1 2 VBIAS 4k VCC – 0.7 • 4k + 32k × R / (32k + R) 2 4k • • VBIAS 4k + 32k × R / (32k + R) • ALC LEVEL ADJ 4k 9 ALC DET 32k R The formula for approximating the value of this resistor is as follows: When pin 9 is open, VOA is preset to – 8dBV (for VCC = 10V). Note that the supply voltage VCC has an effect. Fig.4 VBIAS = VCC – 0.7 2 9pin Voltage = 32k × R / (32k + R) • VBIAS 4k + 32k × R / (32k + R) (2) 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) 2 sec. Min. MUTE CTRL LINE OUT Fig.5 Also, be certain to apply the mute signal when switching between PB / LINE / TU. In the case of LINE / TU switching, it is possible to suppress switching noise by applying a time constant to the signal, in which case it is not necessary to apply the mute signal. (3) Recording control Do not switch the PB and REC modes on together. This will cause faulty operation. (4) Line output The line output can drive a load resistance of up to 2kΩ. Depending on the type of load, it can cause 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. 7 Video ICs BA7797F •Electrical characteristic curves 60 + GAIN: GV (dB) – PB 17 16 12k 330k 40 + 22µ 330 0.01µ 30 20 10 100 1k 10k 100k 1M 10M 10 8 6 VCC = 10V THD = 1% (BW = 0.4 ~ 30kHz) ALC OFF 4 2 LINE GAIN GVR: (dB) 40 1800p 6000p + 1.5k 10µ OUT 4.7k 30 20 10 100 1k 10k 100k FREQUENCY: f (Hz) Fig. 9 Gain vs. frequency (REC amplifier) •External dimensions (Units: mm) 1 9 5.4 ± 0.2 10 1.27 0.4 ± 0.1 0.15 ± 0.1 1.8 ± 0.1 0.11 7.8 ± 0.3 11.2 ± 0.2 18 0.3Min. 0.15 SOP18 8 2k 5k 10k Fig. 7 Line amplifier load drive characteristics VCC = 10V Input: LINE IN Output: REC OUT 3 1k LOAD RESISTANCE: RL (Ω) 50 12k VOUT 0 100 200 500 Fig. 6 Gain vs. frequency (PB amplifier) REC &EQ 10µ RL FREQUENCY: f (Hz) 4 + OUTPUT LEVEL: VOUT (dBV) 50 MAXIMUM OUTPUT LEVEL: Vom (dBV) 10 VCC = 10V VIN = – 60dBV f = 1kHz Input: LINE IN Output: LINE OUT 00 VCC = 10V – 10 VCC = 8.58V – 20 – 30 – 40 – 30 – 20 – 10 00 INPUT LEVEL: VIN (dBV) Fig. 8 ALC input / output characteristics