2-channel PRE / REC amplifier with auto-tracking interface

The BA7180AS and BA7180AFS are PRE / REC amplifiers developed for use in video cassette recorders. They have been designed for use in two-head decks and feature built-in FB damping, two preamplifiers, a chroma output amplifier, an FM output amplifier (with AGC), an envelope detector, a constant-current BTL-drive REC amplifier (with AGC) and built-in channel and REC / PB switches on a single monolithic IC.

Features

1) The playback amplifier has a total gain of 57dB (Typ.), and has a low-noise preamplifier. Designed for VHSband operation with low external parts count.The ICs have 2 circuits for 2-head VCR applications.

2) Two playback output systems (through output and AGC output). The AGC output level is 300mVP-P (Typ.); suitable for FM brightness signal output.

3) Auto-tracking interface for automated tracking adjustment. The detector characteristic is non-linear to improve tracking accuracy during playback of low signal levels.

4) The recording amplifier uses constant-current BLT drive that handles load variations (i.e. head impedance) well, and gives stable recording characteristics. A single circuit is provided for 2-head VCR use.

5) Built-in recording level AGC means adjustment of FM recording current is not necessary.

6) Head switches for 2-channel PRE / REC system provided.

7) Operates off a sigle 5V power supply, with low power dissipation.

Applications

VCRs