TDA1523 is a preamplifier for car radio/cassette players produced by Philips. Its features are two independent amplifiers with an open-loop gain of 90dB, internal DC feedback via a 140 kΩ resistor from output to feedback point, AC characteristics that can be determined externally by an RC network, electronic on/off switching with transient suppression for switch on, head input at DC ground that eliminates the input coupling capacitor, minimum external component requirement, stability down to a gain of 30 dB, low input noise, low distortion, and DC input current less than 2µA.
