How to Make an Amplifier using LM4862Ī general LM4862 based amplifier circuit can be in the following figure. Power supply ripple rejection is superb, which is greater than 50 dB when C2 = 1♟. and to around 250 mA when it is operated at its maximum volume limit.

Total current consumption of the chip can be expected to be around ranges 5 mA in the absence of a music input. Which means the LM4862 can be powered from two or three 1.5 V AAA cells or a from a computer 5 V USB, or simply from your mobile phone charger.īut remember, the supply must not exceed 5.5 V, and therefore even a 6 V supply can permanently damage the chip.

The chip will work with supply voltage ranging from 2.7 V to 5.5 V. This is just enough to create a impressive volume of music volume over 4 inch full range speaker. This means, the amplifier is able to generate a total of 10 volts swing across the speaker from a 5 volt supply. In the BTL operation the two terminals of the speaker are alternately toggled with a +5V and a 0V depending on the music frequency. This differential topology is commonly recognized as BTL (bridge -tied load). The output of the IC LM4862 drives the speaker in a differential mode, which involves opposite push pull waveforms driving the speaker across the two output terminals. The following figure shows the internal structure of the chip LM4862. The input impedance of LM4862 is comparatively low and can be suitably adjusted externally, which ensues that the oscillation issue is kept to minimal. This circuit requires just a single 5 V supply for the operations. When operated at slightly lower power levels, the distortion is reduced to negligible limits.Īnother great feature of the IC LM4862 is its automatic thermal shutdown which protects the chip from damage even if the output is overloaded or short circuited. It is designed to deliver 0.675 watt into an 8-ohm speaker with a total harmonic distortion of 1%. On the other hand, the LM4862 IC is more advanced and slightly more powerful compared to LM386 and it works without any electrolytic capacitor.

Its voltage gain of 20 (or 200 by inserting an additional capacitor) looks quite high for line input level (1 V RMS) and this results in further oscillation issues. As shown below, the LM386 works with large electrolytic capacitors, which makes it bulkier and costlier, and causes it to be prone to distortions with age.Īnother flaw with LM386 is its input impedance which seems to be very high, allowing the chip to be much vulnerable to oscillations if the inputs are not sufficiently isolated from the output.

Pengganti ic lm386