LP2996A: When AVIN/PVIN/VDDQ is below the minimum allowed value, is VTT in tri-state mode?

Louie

Expert 3180 points

Part Number: LP2996A

Hello,

I had a customer ask:

I want to use LP2996 with input voltage range up to 5.5V.

I have only one power supply so I need to connect together pins PVIN, AVIN and VDDQ.

What is the minimum working voltage at this situation?

Are it 2.2V or can it be 1.35V?

What LP2996 is doing with VTT when power supply is lower than 2.2V and/or 1.35V?

Are it became tristate or it’s output voltage is undefined?

I need solution for working output with power supply low as possible and when the power supply is lower than working output so the output will became tristate.

Could you provide me some assistance on the matter?

Thank you,

Louie

over 7 years ago

0 Qian Chen over 7 years ago

TI__Mastermind 24075 points

Hello,

Is the design for DDR application? What's the VTT voltage?

The VDDQ voltage should be higher than 1.35V.
The AVIN voltage should be higher than 2.2V.
If VDDQ and AVIN are connected together, the power supply voltage should be higher than 2.2V to make LP2996 work.
If the power supply voltage is lower than 2.2V, LP2996 may not work correctly and the VTT voltage may or may not in tristate.

Thanks
Qian

0 Louie over 7 years ago in reply to Qian Chen

TI__Expert 3180 points

So it sounds to me then, if the customer ties AVin, Pvin, and VDDQ together, the limiting factor will be 2.2V and the VTT will be limited to 1.1V

Could you find out if it will be in tristate mode?

0 Qian Chen over 7 years ago in reply to Louie

TI__Mastermind 24075 points

Continue the discusstion by email.

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LP2996A: When AVIN/PVIN/VDDQ is below the minimum allowed value, is VTT in tri-state mode?