TPA3251: Slave mode operation

Mochi

Part Number: TPA3251
Other Parts Discussed in Thread: TPA3255

Hello,
Our customer is considering to use TPA3255/3251 as slave mode.
From original E2E thread, it can operate as external clock in configuration. (+) TPA3251: Slave Mode Operation - Audio forum - Audio - TI E2E support forums

Also our customer have confirmed the device function is not degraded within Master clock frequency range in 2.58MHz to 3.75MHz.
Here is our question, do you see any concern to apply clock frequency in between Normal mode, AM1 mode and AM2 mode? Like 3.3MHz, 2.83MHz

I expect those frequency modes are just for AM radio beat avoidance purpose, but D-amp audio performance is not affected even applied those intermediate frequencys to master clock .

Regards,

Mochizuki

over 3 years ago

0 Jesse Ji over 3 years ago

TI__Mastermind 20541 points

Hi Mochi

Yes, your understanding is right.

they are for avoiding AM interference.

one more thing need to consider is the PWM frame rate programming resistor maybe need to re-calculate.

thanks.

Jesse

0 Mochi over 3 years ago in reply to Jesse Ji

Genius 4185 points

Hello Jesse,

Thank yuo for your reply.

The datasheet is stated that “For slave mode operation, turn off the oscillator by pulling the FREQ_ADJ pin to DVDD.”
FREQ_ADJ pin is pulled up, then can we ignore PWM frame rate programming resistor value?

Regadds,

Mochizuki

0 Jesse Ji over 3 years ago in reply to Mochi

TI__Mastermind 20541 points

Hi Mochizuki

yes, it is right.

But if you input fosc out of the spec defined by datasheet.

that means your Fpwm may also out of spec for the relationship between Fpwm and fosc is Fpwm x6 = fosc

we cannot guarantee the usage our of the spec defined by datasheet.

thanks.

Jesse