TPS546D24A: Schematic review

Hi Chandrasekhar,

      Did you use WEBENCH to create the design?

Regards,

Gerold

 Chandrashekhar, in addition to Gerold's question, please upload a higher resolution image of the schematic (or pdf). I cannot make out any component values in the image you posted.

Regards,
Kris

Hi Gerold,

Yes, we used WEBENCH for design and also we referred Reference designs and datasheet.

Hi Kris,

Sorry for the poor image. PFA for the PDF of the same schematic.TPS546D24A.pdf

Thanks, the pdf is a lot better. I will review and get back to you with feedback by tomorrow.

Hi Chandrasekhar,

I have some feedback on your design, and some questions below:

1. R1320 5.11kΩ between VDD5 and BP1V5 is not required for TPS546D24A. You can remove this.
2. Recommend adding placeholders for 10-50Ω in series to VOSNS and GOSNS remote sense lines and a capacitor across VOSNS and GOSNS (e.g. >47pF). This helps filter out some high frequency noise in the feedback, but the cap should be chosen such that the RC cutoff is <= 325kHz switching frequency, so that the filter does not introduce too much phase lag at loop crossover. See the EVM schematic for an example of these components and how they're connected.
3. BCX_CLK and BCX_DAT should be short to PGND per Table 5 in the datasheet.
4. C2170 bypass cap for AVIN pin should go to AGND, not PGND
5. Replace MSEL2 resistor R1311 6.81kΩ lower resistor with value less than 20ohm (or short) for setting standalone mode, TON_RISE to 3ms, and OC_FAULT/OC_WARN to 40/52A.
6. Do you have a load transient requirement (allowed deflection/undershoot for a given load step size)? How did you determine your output cap components and quantity?
7. Do you plan on optimizing the loop compensation through PMBus, or only relying on pin-strapping resistors on MSEL1?

Regards,
Kris

Hi Kris,

Thanks for the review.

6. This regulator is used to power up the peripherals used in the design and hence we considered 50% transient current (i.e 11A). Output capacitors are chosen according to calculations given in the datasheet and also values used in the reference EVM.

7. As of now loop compensation is only through pin-strapping for MSEL1 (I didn't get how to select the option for Loop-compensation through PMBUS).