4 ms·
Agreed. Low-N solutions should optimize for simplicity rather than cost, but simplicity tends to favor LDOs too. PSA: Watch out for residual flux residue on yo
by jjoonathan 4y ago
Agreed. Low-N solutions should optimize for simplicity rather than cost, but simplicity tends to favor LDOs too.
PSA: Watch out for residual flux residue on your voltage dividers! I've seen parallel resistance as low as 50k. If your rails come up at the wrong voltage they can fry your expensive chips! Consider investing in packaged LDOs at the exact voltage you require.
- CamperBob2 4y agoHigh divider resistances are asking for trouble, but very popular in datasheets because they make the efficiency specs look a little better. Residual flux in combination with high resistances is especially scary because the regulator will appear to work "just fine" until some moisture is encountered. Such as when you're spraying R134a around looking for a problem elsewhere on the PCB. Water condenses on the flux near the divider resistors, and now you have (at least) two problems. Another trap for young and old alike is putting your finger on the regulator IC to see how hot it's getting. Touch the 1M resistor next to it by accident, and now your 3.3V bus is more like six or eight volts...