LM386: Unable to hear audio on speaker connected to LM386 amplifier and signal generating from MCU(ATSAMD21J18A) DAC pin3

Hi,

Please can you suggested on hardware and software need any correction in my design. I am using LM386 amplifier and MCU(ATSAMD21J18A),

I am unable to hear audio signal in speaker connected to LM386 3rd pin and signal(Sine wave or .wave generating form MCU DAC pin 3(PA02) pls suggest me to hear audio on speaker.

Hi, Prabhu,

Thank you for providing the circuit schematic. I have some questions regarding the application.

- Could you provide details about the input voltage level at the IN+ pin?

- If you remove the output speaker, do you see any activity at the output pin? Any amplified signal?

- If you incrase the gain with the DNP resistor and capacitor gain components, do you see any difference?

Thank you.

Best regards,
Luis Fernando Rodríguez S.

Hi Luis,

Thanks for helping.

- Could you provide details about the input voltage level at the IN+ pin?

0.125V

- If you remove the output speaker, do you see any activity at the output pin? Any amplified signal?

In schematic i didn't add speaker, but in test case i added speaker(measure voltage in pin5 Vout LM386 IC is 4.56V)

- If you increase the gain with the DNP resistor and capacitor gain components, do you see any difference?

I mounted all DNP components in test time(set 200 gain), but in schematic two are DNP(R95 & C90)

Hi, Prabhu,

Thank you for your responses.

Could you perform the following test?

- Remove all the DNP components.
- Use a 0.5Vrms 1KHz sine wave as input signal. Take a capture of the input and output.
- Perform this test with and without load connected.

Please share the captures in order to have a better approach to this issue.

Thank you.

Best regards,
Luis Fernando Rodríguez S.

Hi Luis,

I will share test report as per your steps.

Thank you, Prabhu,

I will wait for your response.

Best regards,
Luis Fernando Rodríguez S.

Hi Luis,

Circuit is working fine.

Issue: Software (Time delay ).

Thanks for your help.