36 Watt Audio Power Amplifier Using TDA1562Q


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It's based on a Philips class-H audio amplifier IC and can deliver 36W RMS OR 70W music power, all from a 13.8V supply. Our new Mighty Midget Amplifier can really pack a punch - around 36W RMS continuous into a 4-ohm load when using a 13.8V supply. However, it's the 70W of output power that it can deliver during dynamic (music) signal conditions that really make you sit up and take notice.

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As can be seen from the photos and the circuit diagram, the Mighty Midget uses just a handful of parts. It's built on a PC board that measures just 104mm x 39mm but while its size may be modest, these's nothing at all modest about its power output. And the noise and distortion figures are pretty good too.

Circuit diagram:

Circuit diagram

At the heart of the circuit is the TDA1562Q IC, described by Philips as a "monolithic integrated Bridge-Tied Load (BTL) class-H high-efficiency power amplifier". It comes in a 17-pin "DIL-bent-SIL" plastic package and is not only designed for use in car audio and portable PA work but for mains applications as well; eg, mini/midi audio components and TV sound.

Parts layout:

Parts layout

PCB layout:

PCB layout


  • Output power:----------------------36W RMS into 4R
  • Music power:-----------------------70W into 4R
  • Frequency response:---------------1dB down at 28Hz and 55kHz
  • Input sensitivity:-------------------130mV RMS (for 36W into 4?)
  • Harmonic distortion:----------------typically 0.2% (see graphs)
  • Signal-to-noise ratio:----------------95dB unweighted (22Hz to 22kHz)