LDO with good PSRR across Wide Frequency Range

Samuel Jaffe

Other Parts Discussed in Thread: TPS7A3501, TPS7A47

Hi E2E,

My customer is looking at the TPS7A35 but wants a better PSRR across all frequencies. PSRR for this part drops off at higher frequencies (see below). What part do we have that has improved performance in this spec?

Thanks,

-Sam

over 8 years ago

0 Samuel Jaffe over 8 years ago

TI__Mastermind 25590 points

A coworker remembers a part like this. He says it's in the 200mA range.

0 Ryan Eslinger over 8 years ago in reply to Samuel Jaffe

TI__Guru 55940 points

Hi Sam,

First it is important to recognize that TPS7A3501 is not a traditional LDO, but rather a Power Filter. As a result, the PSRR for TPS7A3501 has a different shape than a traditional LDO.

In order to help select an LDO for any application, we need to know a bit about the application. Vin, Vout, and Iout are essential details needed for selection.

Very Respectfully,
Ryan

0 Samuel Jaffe over 8 years ago in reply to Ryan Eslinger

TI__Mastermind 25590 points

Hi Ryan,

We're looking at parts comparable to the TPS7A35 but with 200mA output current, so:

Vin ~5Vmax
Vout ~1.7-4.5
Iout ~200mA

I'm looking for an LDO or power filter, whichever can get better performance at wide-frequency PSRR.

Thanks,
-Sam

0 Ryan Eslinger over 8 years ago in reply to Samuel Jaffe

TI__Guru 55940 points

Hi Sam,

From what I can tell about your application, I believe you are looking for an LDO not a power filter. An LDO will have higher PSRR across more frequencies than a power filter. Take a look at TLV733, TPS7A47 and TPS7A83. Each of these devices has different features and advantages; however, they do all provide good PSRR.

Very Respectfully,
Ryan

0 Samuel Jaffe over 8 years ago in reply to Ryan Eslinger

TI__Mastermind 25590 points

Ryan,

Those look great, especially the TPS7A47. Thank you for your answer. I'll let you know if the coworker finds what he is thinking of. But in the meantime, these are great.

Thanks!
-Sam

Power management

Power management forum

LDO with good PSRR across Wide Frequency Range