AXE022 Regulator marked incorrectly ?

[rjconway]

I posted this onto the yahoo forum however thought I would also include it here for comment.

I just paid the price of a blown PICAXE40x / EEPROM (I think my LCD is OK however PIC gone)....I removed J3 applied 12 V and gone !

I had the flat side of the 78L05 facing the capacitors as "screen printed". Prior to me blowing another PICAXE I checked the regulator and it was shorted in-out. This then led me to do some continuity checks and found the flat side of the regulator should face the PICAXE.

Whats going on with the screen printing of this board ? The only reference to component locations is the printing on the board itself as the instructions had no board layout at all.

Am I dreaming or is this board marked incorrectly, anybody else use the AX022 development board ?

Hi Rob,
I just checked my AXE022 board and found the same as you. Yes the regulator is marked backwards. Fortunatly I had only ever connected mine to an external regulated 5v supply. It might be a good idea to post this info on the Rev-Ed forums.

Glenn.

 

[BeanieBots]

Rob, I agree. Like Glenn I have only ever used the 5v input (j3 made) but the screening is certainly misleading and implies that the tab should be towards the cap. As you correctly point out, the tab should be towards the PIC.
The above is true when applied to a 7805 but the diagram indicates a 78L05 which to the best of my knowledge does not come in a T0220 packeage. The "L" type might have a different pinout and actually be correct when the small plastic package is aligned to the screening. I'll have to check.

After checking several datasheets for the T0 92 package pinout, it would appear that also would result in Vin and Vout being swapped if fitted in the manner implied by the screening.

Users beware !

Edited by - beaniebots on 1/24/2006 6:11:45 PM

 

[Technical]

Thanks for bringing this to our attention, it is a mistake on the silk screen which we apologise for. We will add an errata note to our documentation.

Most users do tend to use 5V or battery inputs, so this is probably why we have not been made aware of this earlier.