Friday, December 27, 2013

LA4440 Amplifier Circuit

LA4440 is a dual channel audio amplifier IC. It can be used in two modes; one is Stereo amplifier and another Bridge amplifier mode. The LA4440 is a monolithic linear IC from Sanyo. Here I give the both circuit mode of amplifier using IC LA4440.

Features of IC LA4440

  • It has 46dB of ripple rejection
  • Low distortion
  • Good channel separation
  • Thermal protector
  • Overvoltage protector
  • Surge voltage protector

LA4440 Stereo Amplifier Circuit

When the IC LA4440 is Stereo mode in the circuit, its output power is 6w+6w. In stereo mode use two pieces speaker of 2Ωto8Ω.
In the stereo amplifier configuration given below, C11 and C12 are output capacitor. But i ignore them from the circuit of bridge amplifier.

Stereo Amplifier Circuit using IC LA4440
Fig-1: LA4440 Stereo Amplifier Circuit Diagram

LA4440 Bridge Amplifier Circuit

When the IC LA4440 is in Bridge mode in the circuit, its output power is 19w. In bridge mode use 4Ω-8Ω speaker. If you want stereo output(19w+19w) in bridge mode then use two copies of amplifier circuit of given below. Resistor R3&R4 is to adjust the voltage gain and for making input signal of inverting amplifier.

Bridge Amplifier Circuit using  IC LA4440
Fig-2: LA4440 Bridge Amplifier Circuit Diagram

Circuit description for both, stereo and bridge amplifier mode


C10 is filter capacitor used to reduce the ripple of supply voltage. Don’t decrease the value of capacitor C6&C7 less than 100uF, 10v, it may causes of the output at low frequencies goes lower. The pin-6 of LA4440 amplifier circuit  is audio input pin; it used in stereo amplifier mode but in bridge mode it is grounded. C8&C9 are polyester film capacitor used to preventing oscillation, and R1&R2 used for the same reason as filter resistor. Though the maximum supply voltage for both circuit of amplifier is 18V but we recommend to use a 12V,3A power supply. Use a good quality heat sink with LA4440.

I think here you see little comparison between stereo and bridge amplifier of LA4440. If you want to make this amplifier project, then I recommend you the bridge one. I think it is ideal for a beginner. And I love its wattage rather than Stereo mode. There is also a possibilities as I say, make two copies of circuit of bridge amplifier for stereo, it will give you 19w+19w of audio power output.