Audio ICs Electronic volume for VCRs and audio devices BA7735FS The BA7735FS is an electronic volume IC developed for VCRs and audio devices. Applications VCRs Features 1) Internal high-performance electronic volume with a dynamic range of 100dB (Typ.). 2) Internal switching between EVR ON and EVR OFF modes. 3) Gain of output amplifier can be set to any value between 0 and 12dB using an external resistor. 4) ±2 power supply supported. Absolute maximum ratings (Ta = 25C) 865 Audio ICs Block diagram 866 BA7735FS Audio ICs BA7735FS Pin descriptions Input / output circuit 867 Audio ICs Electrical characteristics (unless otherwise noted, VCC = 5.0V, VEE = –5.0V, Ta = 25C) 868 BA7735FS Audio ICs BA7735FS Measurement circuit Control pin description EVR ON / OFF This selects the EVR ON or EVR OFF mode. 869 Audio ICs Circuit operation EVR control characteristic Gain control is carried out by means of voltage divider between the GND and the EVR REF pin (pin 2). External dimensions (Units: mm) 870 BA7735FS Operation notes (1) Since muting measures are not taken in the IC when the power supply is turned on or off, these measures should be taken externally if necessary. (2) The gain for the output amplifier should be set to a value between 0 and 12dB. (3) DC offset voltage may be produced, depending on the EVR control point. If this is a problem, insert a coupling capacitor at the point where connection is made to the next stage. (4) If DC offset voltage is a problem when switching modes, countermeasures such as providing a time constant to the control pin (pin 8) can be taken.