TPA3221: The OSCM and OSCP do not have square wave

Yuehai Zhou1

Part Number: TPA3221

Dear all,

I currently designed a EVM board using TPA3221 chip. The voltage of power is 16V. When I power on, I can not see anything from OSCM (PIN 12) and OSCP (PIN 13). The Pin 11 is connected to +5V. The schematic circuit is attached. Could you please help to check it. Thank you very much.TPA3221_PA.pdf

over 5 years ago

0 Robert Clifton56 over 5 years ago

TI__Mastermind 28130 points

Hi Yuehai,

I don't see a 47kΩ pull up resistor on OSCM and a 47kΩ pull down resistor to OSCP. Are they connected?

Best Regards,

Robert Clifton

0 Yuehai Zhou1 over 5 years ago in reply to Robert Clifton56

Prodigy 180 points

Hi Robert,

Thank you for your reply. Are the 47K pull-down and pull-up resistor necessary? When I power on, do I need to reset or take other actions? Are the design for Reset and Cmute correct? Currently, when I power on, there is no current.

0 Robert Clifton56 over 5 years ago in reply to Yuehai Zhou1

TI__Mastermind 28130 points

Hi Yuehai,

Yes these 47kohm resistors are necessary. Please refer to section 9.3.2 Gain Setting And Master / Slave Operation in the TPA3221 datasheet (page 20).

Cmute needs to have a 33nF capacitor to ground. please add that to the circuit. There's not really a need for the 47kohm pull-up resistor on Cmute but I don't think it would cause any issues.

Best Regards,

Robert Clifton

Audio

Audio forum

TPA3221: The OSCM and OSCP do not have square wave