search

speeduino / Hardware

Official Speeduino hardware designs
152 stars 91 forks source link

Power Supply Component Mismatch: Suggested Replacements #19

Open OpenLogicEFI opened 3 days ago

OpenLogicEFI commented 3 days ago

This is for the 0.4.4d board:

Noticed a few components need to be balanced in the power supply. I found some component that could serve as BOM drop in replacements.

D15 has a max Vbr of 49.1v. Too high for D14 (30v) and U8 (35v). -Could swap D15 to SMBJ20A-Q. Vbr is 24.5v.

C21 doesn't meet the ESR requirements of U8 (page 15 - 8.1), which calls for a 'critical' use of 100mΩ - 1Ω ESR.

-Could replace U8 to make it less strict (TLF80511TC / TLE42744GV50ATMA, 400mA max, Automotive) or (LM7805SX/NOPB / LM340S-5.0/NOPB, higher output, easier to get, reliable).

-Or, replace C21 with something like TPSB476K010R0250 (250mΩ) or TPSB476K010R0350 (350mΩ).

noisymime commented 3 days ago

Not sure if I'm looking at a different data sheet or BOM, but the ESR I'm seeing of C21 (EEU-FC1H470B) is 600mΩ, which is very much in spec?

OpenLogicEFI commented 3 days ago

I think you're looking the 0.4.3d THT BOM. I was looking at the 0.4.4d SMD board.

0.4.4d (https://github.com/speeduino/Hardware/blob/main/v0.4/SMD/Latest/v0.4.4d%20BOM.csv)