TPS782 capacitors

Perico Eldelospalotes

Other Parts Discussed in Thread: TPS782

Hello.

In the datasheet of this LDO states that the input and output capacitors should have an ESR of 1 ohm or less. Which is the frequency this value of ESR should be measured?

Thanks.

over 10 years ago

0 Ryan Eslinger over 10 years ago

TI__Guru 55940 points

Hi ,

The ESR requirement should cover the bandwidth of the device. You can estimate the bandwidth of an LDO using the PSRR curve. Take the point at which the PSRR begins to roll off and draw a line -20dB per decade. An estimat of the bandwidth is where the line crosses 0dB.

Very Respectfully,

Ryan

0 Perico Eldelospalotes over 10 years ago in reply to Ryan Eslinger

Intellectual 505 points

Hello Ryan.
Thanks for your help. Maybe it is a stupid question (I am newbie), but what do you want to say when you say "cover the bandwidth of the device"? Do you mean that (in the case of the TPS782) the ESR should be less than 1 ohm at approx. 2 kHz? Or do you mean the ESR should be less than 1 ohm from 10 Hz to approx. 2 kHz?
Thanks in advance!

0 Ryan Eslinger over 10 years ago in reply to Perico Eldelospalotes

TI__Guru 55940 points

Hi ,

The ESR requirement should be met for all frequencies less than 2 kHz.

Very Respectfully,
Ryan

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TPS782 capacitors