The TDA1521 IC type from Valvo / Mullard is a stereo Hi-Fi amplifier that has been designed for TV audio purposes. For the circuit to function optimally, it must be supplied with a +/- 16V supply voltage and can provide a maximum output power of 2×21 Watt at an 8-ohm loudspeaker load. The gain of the amplifier on this amplifier is 30dB per channel.
One special feature of the TDA1521 IC is that it is equipped with auto-mute when there is no audio input. Besides this IC is equipped with auto-mute when given a supply below 6V.
This will be useful when the circuit is turned on or off, it won’t cause noise and the momentary noise that comes out through the loudspeaker. IC TDA1521 is also equipped with a short circuit safety on the output line.
If you are going to install this amplifier circuit, don’t forget to give a heatsink to the IC body because when it works optimally, the IC TDA5121 will give off quite a high heat. If you do not use an adequate heatsink, then the IC risks burning or damage.
The following technical data are stated as typical in the datasheets for the TDA1521 (RL=8 Q; Vs= ± 16 V):
Distortion at Po= 12W: 0.5%
Quiescent current: 40mA
Gain balance: 0.2dB
Supply ripple rejection: 60dB
Channel separation: 70dB
Output offset voltage: 20mV3 dB
power bandwidth: 20-20,000Hz