TP223 replacing a button?

Question

I have a button which does some resistor-alteration:

schematic

^{simulate this circuit – Schematic created using CircuitLab}

Now I wish to replace SW with TP223 (link):

On page2, datasheet mentions TP223 has CMOS output on Q.

I wish to supply TP223 from battery (3V), which is perfectly suitable for it.

How could I replace SW, with its CMOS-output? Easiest would be a relay, but I'm curious if there is any other (simpler) solution.

what do you mean by resistor-alteration? ... is that the actual circuit? — jsotola, Commented Apr 28 at 18:05
It's a sample. Consider a circuit with constant 100R resistance, and SW alters it to 50R. — Daniel, Commented Apr 28 at 18:21

Ale..chenski · Accepted Answer · 2024-04-28 18:59:13Z

1

The TP223 can't be used directly for your task of "resistor alteration". The simplest way would be to use a transistor as a switch:

Now you can use the TP223 to drive the INPUT.

answered Apr 28 at 18:59

Ale..chenski

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\$\begingroup\$ Why R2 is only 98R? \$\endgroup\$
– Daniel
Commented Apr 28 at 19:16
1

\$\begingroup\$ The 98R is because the 2N7002 has typical Rds(on) of 2R. You can choose a transistor with Rds(on) in milli-Ohm range and select the R2 close to 100R. \$\endgroup\$
– Ale..chenski
Commented Apr 28 at 19:36
\$\begingroup\$ In case I have higher supply than 5V, can I still use your solution? Which parameter shall I check in this case (for 2N7002)? \$\endgroup\$
– Daniel
Commented Apr 29 at 4:48

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