I'm looking on the best way to interface 2.2V and 1.8V systems. Direct connection draws ~40uA. I only have 20uA in my budget. I have tried a bus switch solution, but apparently they are optimized more for speed than for power, and all of them contain pullup resistors of 40K or less drawing too much excess current. I need two logic lines down, two logic lines up, and one logic line bi-directional. The speed is not critical to the design. Thanks for any thoughts on this.
Are these standard CMOS I/O signals that you're isolating? And is the 20uA budget for the I/O current draw or for the translation function?
The parts we have available today support interfaces from 3 V to 5 V. I/O voltages are trending toward 1.8 V interfaces, so it's possible that we'll address this in future products.
DaveC, yes these are CMOS I/O signals, and 20uA budget is total from 2.2V system (I/O, Translation, Leakage) Thanks.
The lowest power isolators we offer consume static (quiescent) current of ~0.4 mA/ch, so we don't currently have anything that meets your requirement of 20 uA/ch.
Have you looked at the ADG324x(ADG3242/3243) and ADG330x(ADG3301/ADG3304) families of level translators?
The quiescent current for these is in the uA region and they don't have internal pull-up resistors. Both parts support bi-directional data flow though the channel, but the ADG324x can only perform step-down translation(higher voltage logic into lower voltage logic) while the ADG3300x supports both step-up and step-down translation.
I assumed isolation was required, should've asked. Sorry for any confusion.