Electronic – Help identifying IC – top marking N14D4


I've searched and searched and can't figure out what this thing is. The trace on the bottom is going to a GPIO pin on a micro controller. The top trace goes out to a serial communications line. As best I can tell, the line is a half-duplex open drain serial connection. I think the comms itself is just bit-banged in the MCU.

Partially out of the image is a 5v zener diode. That Zener is being used as a voltage regulator and is connected to a 47.3k resistor, pulling up the comms line. I'm not sure what the resistor between the comms and the second line on the IC is doing, nor the other resistor on the right. All the resistors are 47.3k

Bottom left of the IC goes to ground. I assume bottom right is VDD.

I believe the writing is N14D4 written both directions. Google gives nothing for various combinations.

PCB section and subject IC

Best Answer

Desqa's comment, combined with rdtsc was enough to figure it out. It is functioning as a level shift.

It IS reversible and it's a pair of NPN transistors. I figured it was a SOT6 package, googling n14 sot6 led me to here:


From there, I found DDC114YU, which led me to


That's exactly what it is, the GPIO is triggering the left transistor for transmit mode, and the resistor at the top drives the right transistor when in receive mode.

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