Audio ICs Audio level sensor BA335 The BA335 is a sensor amplifier which consists of three blocks : a small signal audio amplifier, a hysteresis comparator, and a driver. Housed in a 9-pin SIP package, it is optimal for tape recorder end detection and tape mute detection. Applications Tape end detection Tape mute detection Features 1) Built-in comparator with stable hysteresis under power supply voltage and temperature fluctuations. 2) Built-in transistor and diode capable of driving an inductive load at 600mA. 3) Time delays can be created as needed with an external CR circuit. Absolute maximum ratings (Ta = 25C) Internal circuit schematic 829 Audio ICs Electrical characteristics (unless otherwise noted, Ta = 25C and VCC = 9.0V) Measurement circuit 830 BA335 Audio ICs BA335 Attached components C1 : Input coupling capacitor. 1 to 2.2µF recommended. C2 : AC bypass capacitor. 0.1 to 0.47µF recommended. R1, C3 : Resistor and capacitor for setting time delay. R2, C4 : Resistor and capacitor for ripple filter. Input characteristics As shown in Fig. 4, VP6 and VP8 invert when the input reaches approximately 45dBm. VP8 is designed to be able to directly drive the NPN small signal transistor at this time. When on, VP6 is capable of accepting a maximum of 600mA of current (this will vary as shown in the duty cycle table). A continuous ON should last for no more than 3 seconds. Time delay using the hysteresis comparator is as follows. When an input signal of 45dBm or more goes to nothing ceases, the electrical potential of Pin 2 begins to fall due to the CR circuit connected to Pin 2. The time until the hysteresis comparator inverts is the time delay. When deciding the values of the capacitor and resistor, select a resistor value from 100 to 500kΩ. 831 Audio ICs Electrical characteristic curves External dimensions (Units: mm) 832 BA335