LM78L: Cin / Cout Capacitors

taichi

Expert 1395 points

Part Number: LM78L
Other Parts Discussed in Thread: UA78L

Hi, Team

Can customer use ceramic capacitors for LM78Lxx ?

Or may it be possible to use only tantalum capacitors like UA78L?

Regards,

over 8 years ago

0 Mark Sellers over 8 years ago

TI__Expert 7035 points

Hi taichi,

Based on the diagrams in the datasheet it does not look like it is stable with ceramic capacitors. They only show the tantalum capacitors in the datasheet. If you use ceramic you will likely have to add ESR to make the LDO stable.

Regards,
Mark

0 taichi over 8 years ago in reply to Mark Sellers

Expert 1395 points

Hi, Mark-san

Thank you for your reply.
If they use ceramic capacitors, How much resistance should be added to the capacitors ?
Is there a definition of minimum ESR?

Regards,
Taichi Nakamura

0 Mark Sellers over 8 years ago in reply to taichi

TI__Expert 7035 points

Hi Taichi,

I think that tantalum typically have an ESR of ~1ohm. But the best way to tell if the regulator will be stable is to do a load transient and see if there is any ringing.

Regards,
Mark

0 taichi over 8 years ago in reply to Mark Sellers

Expert 1395 points

Hi Mark-san

Thank you for your suggestion.

I will consider it as a reference.

Regards,

Taichi Nakamura

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LM78L: Cin / Cout Capacitors