MAX33221 cap voltage

Patrick Chen(TPE System & Application)

Hi Sir,

I got a question from customer as below, i think they want to know what's the cpa voltage on the C1+/C2- and what voltage cap they need to choose.

Please help.

Could you help to clarify the question for us due to we are choose capacitor for de-rating

For V+/V-, the voltage to GND is +/-7V. I suppose we use 16V cap (50% de-rating) will be fine.

How about C1+/C2+ and C1-/C2-. It is charge pump doubler cap. Will it charge to +/-15V? if it charge to +/-15V as RS232 protocol, we will need to change at least 30V power cap.

Could you help to check C1+/C2+ and C1-/C2- power for us.

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Thanks,

Patrick

over 8 years ago

0 Ron Michallick over 8 years ago

TI__Guru*** 140136 points

Patrick,

C1 is used to boost VCC to V+

C2 is used to mirror V+ to V-.

Therefore V+, V-, and C2 see the same voltage, about 7V maximum.
VCC bypass cap and C1 see VCC voltage.

Add some voltage for design margin. 16V is a conservative choice.

0 Patrick Chen(TPE System & Application) over 8 years ago in reply to Ron Michallick

TI__Expert 3430 points

Hi Ronald,

Many thanks for your help.

Patrick

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MAX33221 cap voltage