TLH7894

April 1987

LM1818 Electronically Switched Audio Tape System

General Description

The LM1818 is a linear integrated circuit containing all of the

active electronics necessary for building a tape recorder

deck (excluding the bias oscillator) The electronic functions

on the chip include a microphone and playback preamplifi-

er record and playback amplifiers a meter driving circuit

and an automatic input level control circuit The IC features

complete internal electronic switching between the record

and playback modes of operation The multipole switch

used in previous systems to switch between record and

playback modes is replaced by a single pole switch thereby

allowing for more flexibility and reliability in the recorder de-

sign

Monaural operation

Figure 9

Features

Y

Electronic recordplay switching

Y

85 dB power supply rejection

Y

Motional peak level meter circuitry

Y

Low noise preamplifier circuitry

Y

35V to 18V supply operation

Y

Provision for external low noise input transistor

Typical Applications

TLH7894 – 1

Order Number LM1818N

See NS Package Number N20A

C1995 National Semiconductor Corporation

RRD-B30M115Printed in U S A