TPS7A49: Noise Reduction/Soft Start capacitor selection/depopulate

Marwan Al-Dulaimi

Part Number: TPS7A49

Team,

Thanks for your help in advance!

In regards to TPS7A4901DGN NR/SS capacitor which suppose to be in there (attached to pin 6). I have this question:

- Can I DEPOPULATE this cap from our design as this LDO is sensitive to very low leakage and if so what may change in this IC (output noise, feedback voltage noise, ..etc)?

Thanks again,

Marwan Al-Dulaimi

over 6 years ago

0 Ryan Eslinger over 6 years ago

TI__Guru 55940 points

Hi Marwan,

Cnr/ss is not required for stability, as such you can depopulate the cap if you wish. By removing the capacitor you will have faster startup and your ac performance will be degraded. Figure 16 of the datasheet shows you the effect of Cnr/ss on PSRR. Figures 19 and 20 show the effect of Cnr/ss on startup time. Figure 26 shows the effect of Cnr/ss on output noise.

Very Respectfully,
Ryan

0 Marwan Al-Dulaimi over 6 years ago in reply to Ryan Eslinger

Prodigy 110 points

Thanks Ryan for your answer.

Best Regards,
Marwan

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TPS7A49: Noise Reduction/Soft Start capacitor selection/depopulate