ADC12DJ3200: Power Sequencing

Amy Luo

Part Number: ADC12DJ3200
Other Parts Discussed in Thread: TPS7A92

Hi team,

Due to stringent requirements for noise performance, one of our customers needs to use 2 LDOs to power digital voltage VD11 and analog voltage VA11, rather than use common 1.1VDC regulator for VA11 and VD11. If VD11 and VA11 are not from the same IC, So how big can the difference between VD11 and VAD11 be allowed during power up/power down procedure? Or, can't use 2 LDOs to power VD11 and VA11 respectively?

Best Regards,

Amy Luo

over 2 years ago

0 Neeraj Gill over 2 years ago

TI__Mastermind 20541 points

Hi Amy,

Customer can use the TPS74401MRGWREP LDO which able to provide 3A of current more than enough to supply both VA11 and VD11.

Regards,

Neeraj

0 Amy Luo over 2 years ago in reply to Neeraj Gill

TI__Expert 6890 points

Hi Neeraj,

The customer's need is not to recommend a power chip with a high output current, but he wants to know if he can use 2 LDOs to power VD11 and VA11 respectively?

Because of the power-up sequence requirements, the customer wants to know how much difference the voltage between the 2 LDO outputs can allow during power up/power down does not affect the power-up sequence, or the VD11 and VA11 must be powered from a common power supply to ensure the power-up sequence?

Thanks,

Amy Luo

0 Amy Luo over 2 years ago in reply to Neeraj Gill

TI__Expert 6890 points

Hi Neeraj,

The customer uses the same DCDC, which outputs 1.6V of intermediate voltage, and then uses 2 pieces of TPS7A92 2A LDO to VA11 and VD11, respectively. In theory, power is powered up at the same time. Is this a viable option?

Thanks,

Amy

+1 Neeraj Gill over 2 years ago in reply to Amy Luo

TI__Mastermind 20541 points

Hi Amy,

Yes if the two LDO's are coming up at the same time it should work.

Regards,

Neeraj

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ADC12DJ3200: Power Sequencing