i've an issue with the AD421 in 4/20mA mode, powered at 3.3V.
I'm using a microchip DN2530 FET transistor.
I've always 16.6mA accross R2, regardless the current order from my microcontroller, when i power-up the AD421 i've 16.6mA and then... no reaction...
My SPI communication seems correct.
Thanks in advance.