BA7746S Rohm, BA7746S Datasheet
BA7746S
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BA7746S Summary of contents
Page 1
... BA7746S / BA7746FS The BA7746S and BA7746FS contains the recording and playback amplifiers required for Hi-Fi VCR signal process- ing. The recording system uses a constant-current amplifier with AGC to eliminate the need to adjust the recording current, and ensure stable operation as the head wears. The IC also features REC MUTE and OVER REC functions. ...
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... PRE IN ch2 PRE AC – FB ch2 N.C. REC + B ch2 REC + B ch1 2 Symbol Min. Typ. V 4.5 5.0 CCS 13 14 AGC BA7746S / BA7746FS Max. Unit 5.5 V REC / PB CTRL 12 REC REC MIX IN OVER REC CTRL 9 8 REC MUTE CTRL VCA CTRL (PRE MUTE) PRE OUT CTRL 3 ...
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... VCA control. • When the terminal is open ( required), the • 6 playback amplifier gain is set to the Typ. value. The PRE MUTE function is made possible by • connection of a mute H signal to this through a diode BA7746S / BA7746FS Voltage Circuit diagram V — CC REC REC: 0.9V PB: 0V 20k — ...
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... REC / PB CTRL REC / PB control pin. • Use circuit time constant to slow the rise • the control signal reduces noise spikes during switching. Do not leave open circuit. • 4 BA7746S / BA7746FS Voltage Circuit diagram V — CC — MUTE REC — OVER NORMAL REC: 2.9V PB: 2 ...
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... The frequency characteristics can be adjusted so • that it is flat with the L value of the rotary transformer, and the external capacitor C (100pF etc.). Voltage REC: 0V PB: 0V REC: 0.58V PB: 0V 38.6mA P-P REC: 4.1V PB: 0V GND REC: 0V PB: 0.8V REC: 0V PB: 0.7V BA7746S / BA7746FS Circuit diagram — 13k 18 5 ...
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... Open emitter output circuit. • Turns on and off in accordance with the REC / PB • control signal. The values given above are design values, they are not ratings and are not guaranteed. 6 BA7746S / BA7746FS Voltage Circuit diagram GND — REC: 0V PB: 0. 13k ...
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... VCA V 2.0 2.6 — OMP V — 0.4 1.0 NP1 V — 0.4 1.0 NP2 BA7746S / BA7746FS = 5.0V, and f = 1.7MHz) CC Unit Conditions mA No signal, pin 1 + pin 7, inflow current mA 10pin 93.0dB IN, 14pin OUT P-P < dB AGC 0.8dB, 14pin OUT 10pin MIXIN , dB 14pin OUT (0.4MHz - 1.3MHz) ...
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... Fig. 1 BA7746S / BA7746FS = 5.0V, and f = 1.5MHz) CC Unit Conditions V Pin 3 DC when ch2 operating V Pin 3 DC when ch1 operating 18, 20pin 0 IN, mV 3pin “H” “L” 5pin OUT V Pin 12 DC for PB mode V Pin 12 DC for REC mode ...
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... Control pin Mode Function REC AMP PRE AMP ON OFF OFF ON Function REC AGC Level 60.0mA P-P 48.2mA P-P Function REC AMP OFF ON Function PRE AMP gain Typ. + 5dB Typ. BA7746S / BA7746FS REC + B SW HEAD SW (P) ON OFF OFF ON 9 ...
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... Application example ch1 ch2 0.047 10 AUDIO HEAD 100p 100p 560 560 560 560 0.01 0.01 0.1 0 PRE PRE ch2 ch1 REC VCA 0.01 1.8k 390 100 0.01 100 5V Fig. 2 BA7746S / BA7746FS 0.1 220k 680 12 220p REC 0.01 0.22 68k 0.1 ...
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... In this case, connect a resistor to the preamplifier output (approx. 390 ). BA7746S / FS PRE HEAD AMP Connection example for BA7746S / BA7746FS and BH780XK series. Output R L Output GND BA7746S / BA7746FS ...
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... IC to function incorrect- ly. Use the current sense pin (pin 14) to monitor the recording current. BA7746FS 10.0 24 7. BA7746S / BA7746FS 0 0.36 0.1 0.3Min. 0.15 SSOP-A24 ...