Audio ICs Dual recording / playback preamplifier for radio cassette recorders BA3420AL The BA3420AL is dual recording / playback preamplifier for radio cassette players. It has an internal switch for switching between playback head, mic, and radio input modes, and also includes a bias oscillator and regulated voltage source for radio use. All control is possible with one external switch, allowing designers to reduce the number of external components and the size of their set designs. Applications Radio cassette recorders Features 1) Internal three-mode input / output switch for playback head, mic and radio modes. 2) Built-in bias oscillator and regulated voltage source for radio use. 3) Control of the internal switch and regulated voltage source is possible with one external switch. 4) Low distortion. 5) Low noise. Absolute maximum ratings (Ta = 25C) Recommended operating conditions (Ta = 25C) 243 Audio ICs Block diagram 244 BA3420AL Audio ICs BA3420AL Electrical characteristics (unless otherwise noted, Ta = 25C, VCC = 8.0V, f = 1kHz and measurement circuit: Fig. 1) 245 Audio ICs Measurement circuit Measurement circuit switch control table 246 BA3420AL Audio ICs BA3420AL 247 Audio ICs Application example 1 Application block diagram 248 BA3420AL Audio ICs BA3420AL Application example 2 249 Audio ICs Electrical characteristics curves External dimensions (Units: mm) 250 BA3420AL