During product stand-by mode the TAS5706B is powered off by turning off supply voltages. Also during stand-by mode the AVDD (pin10) is exposed to periodic pulses caused by other parts in the design (for auto-power-up on signal). The failure is audible on the connected subwoofer as periodic clicks/pops on the SUB_PWM+ output, during the standby mode of the system.
To find the cause of the problem we have tested identical PCB’s equipped with different TAS5706B devices. On a PCB mounted with TAS5706B 41A28GTG4 we see and hear the failure, whereas on a PCB with TAS5706B 21A358TG4 there is no problem.
And by exchanging[1] TAS5706B 41A28GTG4 with TAS5706B 21A358TG4 the pop-noise on the subwoofer output disappears.
The question is what is causing the failure and what the difference is between the two parts.
[1] System with pop-noise on SUB_PWM output: TAS5706B 41A28GTG4. System without pop-noise on SUB_PWM output: TAS5706B 21A358TG4
