Power amplifier Output Distortion Apex PA02 Amplifier IC

Thread Starter

saneeshforu

Joined Feb 22, 2014
8
Hai all, I am facing an issue related with power amplifier design. I am designing an amplifier with apex PA02 IC (50W Class AB) the problem is when i am working with lower frequencies (less than100kz) (Input voltage is sine 1 Volt peak to peak ) it is working fine but when i am increasing frequency like about 200khz the output wave is distorting. Supply voltage is 12vdc and load resistance is 500R. IC Data sheet saying band width of 350Khz and slew rate of 20V/uS. On my observation i found that when i reduce the input voltage to 0.5 volt pk to pk the output can vary up to 250 Khz without much distortion. Here i am attaching circuit diagram and distorted wave forms Please help me
Thank in advance
San Geo
 

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fourtytwo

Joined May 2, 2017
80
Something is odd, your scope shot amplitudes don't match your signal generator amplitudes times the gain.
Are you sure your signal generator output is clean ?
The load is a very high resistance for this device, have you tried much much lower in line with the data sheet ?
 

Thread Starter

saneeshforu

Joined Feb 22, 2014
8
Something is odd, your scope shot amplitudes don't match your signal generator amplitudes times the gain.
Are you sure your signal generator output is clean ?
The load is a very high resistance for this device, have you tried much much lower in line with the data sheet ?
Thanks for your reply
Signal generator output is perfect gain about 4.3 and signals at the input of amplifier is perfect even when the out is destroyed. Upto170 Khz output is fine. Please help me
 

KeithWalker

Joined Jul 10, 2017
1,409
The specifications are for a 10 Ohm load. It does not mention how it will behave with other resistive load values. If you really need to use it up to 300 KHz, all I can suggest is to try using frequency compensation in the feedback. Good luck.
Regards,
Keith
 
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