Amplifiyng ISD1820 with PAM8403 module

Other Hardware General Electronics
1

Hi,

I'm trying to amplify sound of isd1820. I bought pam8403 ic module .
I first connect SP - pin of isd1820 to ground pin of Pam(input) .Then I connected SP + to L or R pin of pam. ANd then I fully hear distortion.

What is the way yo connect isd1820 to pam8403 module? I'm little bit confused :confused:

Best regards,
Tugce.

2

No, look at the datasheet, there are coupling capacitors on the inputs in their example circuit, they are required.

[ Actually the docs for the ISD1820 don't say if its analog or class D output for the speaker - if its class-D you cannot do this at all ]

3

The pam6403 has a voltage gain of about 20 - so will be greatly overloaded by the ls output of the isd1820

Fit a 20dB attanuator/ 10kHz lowpass filter between the two - see attached.

This should deal with any pwm as well...

regards

Allan

if2.pdf (15.4 KB)

4

If its class-D, you can't necessarily assume you can use just SPK+, since its a differential signal

5

Thanks for replies

Pam module has 3 input pins namely l r and ground. In thus case how i can connect depending on your suggestion? Also,with using capacitors as isd data sheet, is it ok for pam module as well? If so how?

Sorry for asking again, but im really confused

Best regards

6

MarkT - the 1820 output could be an h-bridge with PWM - the filter should help.. Just use 1/2 the bridge.

edit: the pam module is capacitor-coupled, so dc isn't a worry. /edit

yuno - OK I'll spell it out. See attached.

The pam is a STEREO amp. so just use one channel - I've shown the left.

Note you CAN'T parallel L+R for more power.

regards

Allan

tf3.pdf (16 KB)

7

allanhurst, thanks for detailed answer.

I'll try whenever I buy 22n capacitor

I'll let you know about result :slight_smile:

Thanks

Regards,