People, I have very basic question on 'How to make a switch using a PMOS' transistor.
Following are the specifications:
Drain – Output Pin
Source – 4.2V (From Lithium-ion Battery)
Gate – 3.3V / OV (Control Pin)
I am using NDS8434 PMOS. Gate threshold for this is less than -1V.
Question:
Ideally, if I am connecting Gate to 3.3V then PMOS should be OFF and when I am connecting 0V then PMOS should be ON, But this is not the case?
Best Answer
You need to level shift your 3.3V to 4.2V to use a pmos device use a circuit like this.
simulate this circuit – Schematic created using CircuitLab
Note The polarity of the input is changed the pmos transistor will be on when the input is high.