SN74HC590A: Low Pulse Volgage Level on RC0

RCO is a push/pull output and should be able to drive a small load without a pullup.

What exactly is connected to this pin?

It's connected directly to an input of a micro controller. Saying that, I have not set it up as an input yet. I will check in the morning.

Hi,

Let us know if that resolves the issue. This could be caused by bus contention, if the MCU I/O is an output.

Hey Guys

OK, I have set the MCU pin up as an input. This has not resolved the issue, please see scope trace below of the RCO and QH. There is nothing else connected to the net and the only external components is a 0.1uF bypass cap.

Thanks

Please zoom in on one of those pulses, and show it together with CCLK.

Sorry for the delay, here is the zoomed in image. The Clock frequency has changed (as the rest of the project progresses in testing) but hopefully this shows what you are looking for.

Thanks

The timing and the edges appear to be OK.

I am not aware of any defect in the device itself that could cause this problem. I guess that there is a short between this signal and ground, with a resistance of about 16 Ω. (Check with a multimeter.)

Hi,

Yes this is unusual. The part is likely damaged. Do you have any extra devices that you can replace this device with to verify?

Hi Dylan

Yeah, I can't seem to find any shorts, I have other to replace it with if need be. But for the time being its not critical as this is just a test piece before I commit to the production design.

Thanks