Recently I used an N-mos tube to make an IIC level matching circuit. The first tube I used was ao3402. I found that the device was not working properly. I changed the tube to 2SK3019 and the circuit can work normally. I checked these two tubes. In the specifications, the parameters related to level matching may be about the same as the turn-on rise time, turn-off fall time, and voltage drop. The only difference that makes me care is their power consumption and static drain-source on-resistance. A tube with a low power consumption and a large resistance is enough. The great god will guide you how these two parameters affect the level matching circuit, and what is the reason? I am not good at learning, just laugh.
AO3402 N-ch 30V 4A 55mΩ 1.4W SMD SOT-23
2SK3019 150mW static on resistance 5Ω
Lyon Posted on January 29, 2021
No circuit, you can't see it in detail. However, the parameters of these two tubes are quite different. One of the bulk resistance is mΩ and the other is Ω. Also, pay attention to the VGS voltage difference in your circuit.
Cass Posted on January 29, 2021
2N7000 should work.
Shahid Posted on January 29, 2021
Use a tube with a small gate capacitance/Qg. AO3402 is a tube used for high-current switching, and its high Qg value is not suitable for this place.
