How to generate -0.9V out from -5.2V?

Jianxiong Zou

Other Parts Discussed in Thread: LMH6554, TPS7A30

I am using the LMH6554 which needs -0.9V for the negative power supply (low noise required), but I just can't find a suitable LDO regulator...

So, is there any solution for that? thanks.

over 13 years ago

0 Sureena Gupta over 13 years ago

TI__Intellectual 1130 points

you can reference a negative LDO, like the TPS7A30, to a positive rail to achieve a -0.9 Vout.

Also, assuming that the -5.2V rail is fairly stable and low noise (though you could use an RC filter to clean it up) you could also use this same -5.2V voltage to offset the reference voltage at the feedback pin to get the LDO to set a Vout voltage lower than its own reference.

Regards,

Sureena Gupta

0 Dongdong Ying over 12 years ago in reply to Sureena Gupta

Prodigy 20 points

Hi Sureena,

Can you specify how to use TPS7A30 to generate a -0.9V Vout more detailedly? I'm in trouble on how.

Thanks.

0 Darwin Fernandez over 12 years ago in reply to Dongdong Ying

TI__Mastermind 41760 points

Hi Ying,

Please see the below app note regarding how to regulate an output voltage lower than its reference. By biasing the resistor divider network differently, one can achieve this.

http://www.ti.com/analog/docs/litabsmultiplefilelist.tsp?literatureNumber=slva216&docCategoryId=1&familyId=659

Regards,

Darwin

0 Dongdong Ying over 12 years ago in reply to Darwin Fernandez

Prodigy 20 points

Darwin,

Thank you very much for your reply, it helps.

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How to generate -0.9V out from -5.2V?