I've somehow damaged one my cheap atTiny 88 boards:
It no longer powers up, presumably due to the burnt out component that was in the location highlighted here: .
A bright light and magnifying glass reveals the marking on one of the undamaged ones as 'S4'.
Can anyone identify the component please? I'll try to replace it, although probably not with a surface mount type.
It is a diode D3 in below picture that is part of the protection of the USB port.
It most likely will get blown when you connect the VCC pin of your MH-Tiny to GND when powering from the USB.
The other two with the SMD marking W4 are the two zener diodes D1 and D2
(I know this is a schematic of a Attiny85 board, but the idea around the USB port is the same).
Thanks, appreciate that helpful reply.
I'm a bit puzzled about the USB socket '5V'. If that's 5.0V from the PC, doesn't that imply only about 4.4V on the Tiny? Or 4.8V if it's a germanium diode?
It's probably a Schottky diode with a drop of about 0.3 ~ 0.4V, though that schematic shows a "regular" silicon diode with a 0.6 ~ 0.7V drop.
Nano's use that scheme and usually have a Vcc of 4.6 ~ 4.7V
From the Nano schematic:
My spec sheet for the S4 diode says:
Schottky barrier diode
40V @ 350mA continuous and 1.5 A repetitive @t<=1.0sec.
Vf = 0.37V @ If = 20mA and 0.6V @ If = 200mA.
Thanks, I’ll look to order some or similar.
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.
