Electronic – I’d like to replace NPN transistors with NMOS in this simple circuit

esp8266mosfetnpntransistors

I'd like to replace a pair of NPN transistors and their associated base resistor with two small N-channel MOSFETs, such as the ESD protected 2N7002K.

I've drawn the two versions of the circuit (left side is known good, right side is what I'd like to do) but I have no idea if it's going to work. PCB fabrication takes time and I don't have the parts on hand to prototype…

Should my replacement circuit work like the original, or am I misunderstanding something important?

Thanks!

Left-side: original circuit, right-size: what I'd like to do

See also:

Work in progress: the project this is going to be used in,

Example of the circuit used on the NodeMCU devkit
Networked Thermocouple Reader with Integrated Display

Okay, it took a while for me to receive the 2N7002K, but now I can confirm this modification actually works! All seems good on my modified WeMos D1. Now I'm waiting for my own circuit to come back from the PCB fab, and I'll test the modified circuit again and report on the results.

Original circuit
Modified circuit

Replacement solder is Sn42Bi57Ag1 and it looks a lot shinier than the original lead-free alloy.

Best Answer

One issue is that in your FET circuit the gates are exposed directly to static on the RTS and DTR lines, this may result in damage to the FETs. In this application BJT transistors are more robust.

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