Other Parts Discussed in Thread: ISO6740, ISO7740
Hopefully an easy question...
I'm looking for something that will do a level shift from a 0V/3V3 digital control signal to +/-2V5 (signals to control a split-supply amp, where they have to be referenced to -2V5 rather than 0V. The normal level translators aren't any use because they expect a common ground reference on both sides.
I think I can use the ISO7140, but it's not clear from the abs. max ratings whether or not I can have a voltage difference between the two grounds. I want to connect the supplies as follows:
GND1: 0V
VCC1: 3V3
GND2: -2V5
VCC2: +2V5
I can do it quite simply with a couple of FETs and resistors as per diagram below, but would like something that can switch a bit faster and 4 channels in one package would also help so a 4-channel isolator looks a good option. Is it OK to connect it like that?