BA3304F

Audio ICs 3V dual preamplifier BA3304F The BA3304F is a monolithic, dual-preamplifier IC designed for 3V applications. It has been designed especially for lowvoltage operation. The preamplifiers can be directly coupled to the head to minimize the “pop” noise at power on. When combined with the Rohm BA5204, it is a simple matter to design a high-performance circuit for cassette players. FApplications 3V headphone stereos, 3V micro-cassette players and low-voltage stereo equipment FFeatures 1) Low noise (VNIN = 1.2µVrms). 2) Input coupling capacitors not required. 3) No input coupling capacitors means high bass stability. 4) Good channel balance. 5) Built-in bias circuit minimizes “pop” noise. 6) Emitter-follower output for low output impedance. 7) Good low voltage characteristics (operation possible from Typ. 1.2V). FBlock diagram 178 Audio ICs FAbsolute maximum ratings (Ta = 25_C) BA3304F FInternal circuit configuration FDescription of circuit (see Fig. 1) As shown in the equivalent circuit for the BA3304 in Fig. 1, the first stage is a differential amplifier. This gives good stability with respect to temperature and supply voltage variation, and improves resistance to earth and power supply noise. The second stage uses Darlington pairs to increase the input impedance and the gain of the first stage. The output is an emitter follower which suppresses deterioration of the linearity due to the influence of the equalizer terminal, and prevents drop in maximum output. ...