# Switching device for ultra-low power sub-circuit

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
• 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?

• This looks like a shopping question, which is considered off topic (Stackexchange considers such questions to not be timeless enough). Questions about what technologies to be considered for this would be on-topic, though. Jan 5, 2020 at 19:44
• @TimWescott, by switching device I meant anything that acts like a switch. Normally, in a non low power application I would have used MOSFET. So, before posting this question I searched for MOSFETs, but I did not found a suitable one. Then, I looked for other devices types (technologies), found some good ones, but there may be some better options. Also, there may some better suited device types, technologies, or techniques am simply I'm not aware off. Jan 5, 2020 at 20:01
• What do you exactly mean by "PFET"? P-channel MOSFET? I'm interested in ultra-low leakage currents (in any direction) in the OFF state. P-channel MOSFET-s, the better ones, seems to have "Gate-Source Leakage (IGSS)" of max 100nA, "Zero Gate Voltage Drain Current (IDSS)" of max 1μA. I'm looking for values around 0-5nA. Jan 5, 2020 at 21:08
• @bluetiger9 What about this? I note that it appears to have fairly low leakage specs. (I didn't look at much else.) The other thing to note is that even if very clean, the bulk impedance of an epoxy package is on the order of $1\times 10^{11}\:\Omega$. If it is in any way dirty, that goes way down and fast. Keep things clean. I had a case where I needed nearer $1\times 10^{14}\:\Omega$ and so I had to accept dice, instead.
– jonk
Jan 5, 2020 at 22:32
• @jonk, the TI CSD15380 you linked looks very similar to the TI CSD23280 I looked at. This epoxy + dirt thing sound interesting. Thanks for drawing my attention to this :) Jan 6, 2020 at 18:55