LM51231-Q1: Request for schematic design review

Hello Jeffrey,

Is there a reason why the LM51231 has been chosen instead of the LM5123?
Please note that the LM51231 is NOT a newer and better version of the LM5123.

Fundamentally, the schematic looks good to me.
It seems that the values of the components (e.g. compensation network) have been calculated with our QuickStart calculator, which is good.

In general, in case of a BOOST converter, the output capacitors are more important than the input capacitors.

Therefore, there is one change that I would strongly recommend:
Please move 3 out of the 5 ceramic 10µF capacitors from the input to the output side (C4, C5, C6).
Big enough ceramic capacitors are important because the electrolytic capacitors are not fast enough to store the energy that is transferred within each cycle.

A small capacitor (maybe 470pF) from VREF to AGND would also be good to have.


For the layout, please follow the deign rules that are given in the datasheet
and do not use any thermal-relief connection for any component of the power stage nor for the capacitors on the VCC pin and the HB pin (C29 and C27).

All information in this correspondence and in any related correspondence is provided “AS IS” and “with all faults” and is subject to TI’s Important Notice: http://www.ti.com/corp/docs/legal/important-notice.shtml

Best regards
Harry