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.
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:
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:
PCB layout:
Performance:
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)
Source: Silicon Chip March 2002