Part Number: ADS1281EVM-PDK
Why is GPIO3 high? - I want Bipolar mode.
I have the ADS1281 EVM PDK kit.
I'm using it in Bipolar +/-2.5V mode.
I've discovered on the ADS1281 EVM that GPIO3 is high, which (post inverter U8) is disabling the Regulator and shorting the ADC AVSS line to 0V.
(This is destroying my external VA power (+/-5V) and reference (+/- 2.5V) - actually it is destroying my -5V - which then upsets my -2.5V REF).
GPIO3 is controlled by something on the MMB0 PCB. Rev D 2009. Bom Rev F.
I feel that the MMB0 must sense the -5V rail (Bipolar mode) and set GPIO3 low. Or is it something else?
How do I get GPIO3 to go low? Have I got a link missing?
I'm using external supplies for +/-5V VA analog and an external 5V digital. I don't have J13A (+VA to 5V) or J13B (+5VA to 5V) link installed. My MMB0 layout doesn't match the manual and the manual isn't very clear on the correct way to set these two.
Thanks
Peter Baxter