Regulator output voltage is wrong
Opened this issue · 3 comments
Installed the AP2210 adjustable regs on the test board.
Board appears to boot and can be communicated with over serial.
Output of 3.3V reg is just under 2.1V.
Noise seems reasonably under control.
There seems to be noticeable ripple in the supply at 1ms intervals (corresponding to the LED switching/micro doing processing on tick timer from sleep).
Scope traces for record. Set to AC coupling.
- Pulled R3 (51k) and R4 (82k) resistors for the 3v3 reg off the board.
- They measured at 50.8k and 83k which is within tolerance.
- Replaced with new resistors which tested at 81.9k and 50.98k.
As per datasheet, VOUT=1.25V*(1+R2/R1) where R1 is the 51k selected. This gives VOUT of 3.295V.
Still not sure what's going on with it...
All regulators are wrong...
Decided to look at the other regulators when the camera was spitting out garbage. I should have checked this earlier.
Input voltage is 5.01V from the USB-UART adaptor -> USB hub.
The 1.3V reg is outputting 4.30V.
The 2.8V reg is outputting 2.44V.
The 3.3V reg is still outputting ~2.2V.
This is really wrong, and I wouldn't be surprised if the actual sensor core was irrevocably damaged by ~3x recommended voltage, and the datasheet states a absolute max 3V...
WTF
Maybe junk regulators? The marking on the regs show AEAD with some orientation marks and bars/dots above/below some letters. This code doesn't match up with any of the tables in the datasheet.
I'm not even sure what these are anymore... Real stock seems to be at least 2 months away.
Datasheet issue
I've been reading a AP2210 from the RS website. Its branded as BCD manufacturer while the real Diodes Inc datasheet is laid out slightly differently (there should be a logo on the package is the only difference). The Vout formula, pinout and package markings seem to be otherwise identical.