TPS51200 DDR3 Module

Mehrdad Bradaran

Other Parts Discussed in Thread: TPS51200

Hello,

My customer is using P/N: TPS51200 switcher to generate Vref and VTT for their DDR3 module. By using the Micron 4Gb module MT8KTF51264HZ-1G9,

the VTT output (DDR3_VTT pin at TP38 on the schematic) is oscillating at 4.5 Mhz unloaded and it is at about 5Mhz when they load the DDR3 module.

The oscillation problem goes away when they swap the DDR3 with a 1Gb module, P/N: MT8JTF12864HZ-1G6G1.

Can you please advise.

Thanks,

Mehrdad.

over 9 years ago

0 Qian Chen over 9 years ago

TI__Mastermind 24075 points

Hello,

The schematic shows there is only 330uF polymer cap on VOUT. Is there any ceramic cap on Vout?
If not, please add several 10uF ceramic caps and placed caps close to VOUT pin to see if the issue goes away.

Thanks
Qian

0 Mehrdad Bradaran over 9 years ago in reply to Qian Chen

Intellectual 430 points

Thank you, Qian. Why do we need needs caps?

Mehrdad.

0 Qian Chen over 9 years ago in reply to Mehrdad Bradaran

TI__Mastermind 24075 points

Hi Mehrdad,

When there is only polymer cap and the polymer is not very close to VO pin, the regulator might not in stable operation.

Can you try my suggestion?

Thanks

Qian

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TPS51200 DDR3 Module