BA3708F

Audio ICs Mute detector IC for 3V sets BA3708F The BA3708F is a mute detector IC for 3V tape players. When the signal is higher than the input decision level VIN and longer than the song detect time, a pulse of width TW is output after the pulse delay time TD which begins when the input signal ends. The output is an open collector which enables direct drive of the plunger. A mute function is included which makes it possible to stop detection. FApplications 3V tape players FFeatures 1) Low supply voltage (can be operated at 1.8V; recommended operating voltage is 2.0 to 5.0V). 2) Uses the song detection method to minimize incorrect detection caused by noise between songs. 3) The pulse delay time TD, pulse width TW, and song detect time TC can be set using external CR time constants. FAbsolute maximum ratings (Ta = 25_C) 4) Includes a mute circuit which makes it possible to stop song selection. 5) Built-in output transistor enables direct drive of the plunger. (IO Max. = 100mA) FRecommended operating conditions 738 Audio ICs FBlock diagram BA3708F FElectrical characteristics (unless otherwise noted, Ta = 25_C and VCC = 3V) 739 Audio ICs FMeasurement circuit Switch operations BA3708F FApplication example 740 Audio ICs FCircuit operation (1) Input amplifier The input amplifier is a PNP differential amplifier, and the input pin (Pin 3) must be directly connected to ground through a 10kΩ or less bias resistor (RIN). If RIN is too large, an input offset may occur and ope...