I'm looking for a switching device to be used for powering a sub-circuit in a battery powered low / ultra-low power circuit.
It can be a MOSFET, or something similar but it need to have some special properties.
The sleep mode power consumption of the circuit, without the above sub-circuit + switching device, will be in the range of 25-50nA @3.3V.
The ON current for the sub-circuit is expected to be ~25-50μA, with occasional spikes of at most 10-20mA.
Because the above currents are very small, I think we need a low power switching device with very small leakage currents. This way the sub-circuit should not gets accidentally powered and the power consumption in sleep mode is kept at minimum.
As far as now, I looked at following options:
- MOSFET-s:
- Vishay, Si1499DH – MOSFET, source-drain leakage current 1μA/10μA, gate leakage current 100nA
- Texas Instruments, CSD23280F3 – MOSFET, source-drain leakage current 50nA, gate leakage current 25nA
- load switches
- Texas Instruments, PS22860 – load switch, leakage current 10 + 2 nA
- Vishay, SiP32431/2 – load switch, leakage current 0.001nA, with 100nA max @3.3V (note: found this after posting the question, and looks to be good enough)
- some JFET-s, but I'm not sure if they could be used / are suitable for such an application
Now, may there may be a lot of devices / solutions I'm not aware of. What do you think are the most suitable devices or solutions for such a problem?
Best Answer
Because you've done some adequate research into a solution and have put together a half decent requirement I'm making an answer...
The ADG819 2:1 multiplexer operates from 1.8 volts to 5.5 volts and has a maximum D-S leakage current of +/- 10 nA across the full -40 C to +125 C temperature range. On-resistance is 0.8 ohms maximum and this would result in a volt drop of 16 mV at 20 mA current through the channel.
If you want more switching options the ADG1604 (4 channel multiplexer) is also pretty useful. On resistance is 1.6 ohms and D-S leakage is 16 nA max.