Friday, 19 January 2018

LM3886 for lower bands

DIY audio fanatics appreciate this ‘chipamp’ a lot. See for example

                                 LM3886 as 65 Watt audio amplifier

It provides 65 Watts audio into 8 ohms. Audio quality is more than all right. PCB’s with this chip are available for about 10 euro’s (eBay, Aliexpress). 

Bunch of low-cost LM3886 PCB's (10 euro each)

The frequency response curve shows that we are dealing with a broadband amplifier. @ 200 kHz the attenuation is only 1.7 dB !

Frequency response

Therefore, this chip should be able to be used as an RF amplifier for the 2200 m band (135.7 – 137.8 kHz) and lower bands.

A challenge for the designer is of course to adapt the 8 ohms output to the antenna impedance.