ChipKIT Max32 NCP1117 incorrect IC?

Created Sun, 15 Jul 2012 02:59:36 +0000 by jsmith1357

jsmith1357

Sun, 15 Jul 2012 02:59:36 +0000

I'm working on a project for PIC32 architecture and using the Max32 board as a development tool, and I noticed something strange about the two boards I've ordered.

The onboard 5V regulator used to step down the barrel jack input voltage is listed on the schematics from Digilent's site as a NCP1117DT50, but the IC on both boards I've ordered (one several months ago and one just a few days back) appear from their case markings to be NCP1117DT33 parts. Indeed, if I apply any voltage from 6-12 volts at the barrel jack with the power jumper in the REG position, I get 3.3 volts on the 5V0 pin.

Does anyone know if this an intentional design change, or if I just got a board with the wrong part for IC4?

Here's a photo of the most recent board I ordered (IC4 marked 17L33):

Jacob Christ

Sun, 15 Jul 2012 07:02:15 +0000

Considering there is also a 3.3V regulator as well, this sure seems like a mistake to me.

Jacob

jsmith1357

Sun, 15 Jul 2012 19:42:35 +0000

Yeah, the MCP1725 3.3V regulator on these boards is still present and working fine. If I change the regulator jumper to BYP and apply 5V to the barrel jack everything works as intended.

majenko

Sun, 15 Jul 2012 23:04:40 +0000

That certainly sounds like a manufacturing error to me. I suggest you contact Digilent support directly at support@digilentinc.com

GeneApperson

Mon, 16 Jul 2012 18:50:09 +0000

This is a manufacturing error, it was not an intentional design change. I'm investigating what happened. If you want your boards replaced, contact support@digilentinc.com and we'll RMA them.

Gene Apperson Digilent

spcomputing

Mon, 23 Jul 2012 03:44:10 +0000

Nice form, jsmith1357.

Working in the semiconductor industry for 15+ years, I can understand the catastrophic "opps" that occurs from time to time.

Being constructive to the possible 8D "containment phase", I have only one UNO32 with the correct voltages (verified by multimeter, 3V3 = 3.32 volts and 5V0 = 4.8 volts). 5V0 Regulator ID is RUY 17L50 and I don't have a microscope for the 3V3 IC.

Barcode is D410528. QC11 OK. Silkscreen ID PIC-M2V-0 94V-0 1203.

Looks like Max32 Production Line.

jsmith1357

Thu, 26 Jul 2012 12:49:42 +0000

For the moment, I'm just using an external 5V regulator and switching the jumper to the "BYP" position. This works just fine for the testing setup I'm using, but I just wanted to make sure that this wasn't a problem with the documentation.

Thanks for all the helpful replies!

cgclepper

Tue, 14 Aug 2012 00:15:17 +0000

I just got bit by this problem. My project has a 16x2 LCD and all is well using the USB for power, but switching to external DC the display stops working!

I just emailed Digilent for an RMA, I can report back on how that goes.

prabhatlall

Fri, 19 Jul 2013 17:28:09 +0000

i had a similar problem with the lcd not working with external power