PCM6240-Q1: external LDO under BSTOUT

Atsushi Hirai

Part Number: PCM6240-Q1
Other Parts Discussed in Thread: TPS7B4250-Q1

Hi team,

Is it okay that we add a 50mA~100mA external LDO or tracking LDO(track/copy the MICBIAS voltage) under boost output if 80mA is not enough?

Please give me your advice.

Regards,

over 2 years ago

0 Carson Allen over 2 years ago

TI__Genius 13610 points

Hi,

Yes this is possible, you would just need to make sure to set MBIAS_HIGH_CURR_THR S[7:0] register accordingly.

Best,

Carson

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0 Atsushi Hirai over 2 years ago in reply to Carson Allen

TI__Expert 3610 points

Carson-san,

thanks for your advice.

I have two questions.

1) where is the current for MBIAS_HIGH_CURR_THR monitored?(output of boost circuit or input/output of integrated LDO)

2) does the boost converter have switch current limit? If yes, what is the threshold?

Regards,

0 Carson Allen over 2 years ago in reply to Atsushi Hirai

TI__Genius 13610 points

Hello,

I will need to check with systems team on this, I appreciate your patience,

Best Regards,

Carson

0 Atsushi Hirai over 2 years ago in reply to Carson Allen

TI__Expert 3610 points

Carson-san,

Got it. I'll wait so, please update.

0 Carson Allen over 2 years ago in reply to Atsushi Hirai

TI__Genius 13610 points

Hello,

MICBIAS and Boost have independent thresholds but limit to 100mA and device should work, though we do not directly say in datasheet as this being an acceptable mode of operation and it is not guaranteed to fufil all specs that are laud out in datasheet if it is chosen to be used this way.

Best,

Carson

0 Atsushi Hirai over 2 years ago in reply to Carson Allen

TI__Expert 3610 points

Carson-san,

Could you confirm which parameters may be exceed the datasheet spec if customer connect TPS7B4250-Q1(50mA tracking LDO) to BSTOUT and consume 100mA totally(MICBIAS+TPS7B4250)?

Best Regards,

0 Carson Allen over 2 years ago in reply to Atsushi Hirai

TI__Genius 13610 points

Hello,

I am speaking of this section noting 80mA is max drive current of MICBIAS

Best Regards,

Carson

+1 Atsushi Hirai over 2 years ago in reply to Carson Allen

TI__Expert 3610 points

As we discussed offline, the output current from BSTOUT should be limited up to 80mA.

I'll change my proposal if my customer need >80mA output.

Thanks,

Audio

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PCM6240-Q1: external LDO under BSTOUT