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CD4010B-Q1: powering board through level shifter

Part Number: CD4010B-Q1
Other Parts Discussed in Thread: CD40109B-Q1,


I was previously using PN# CD40109BQNSRQ1 to level shift from 12v to 3.3v. I needed extra inputs so changed to PN#CD4010BQDRQ1. I am currently running vehicle turn signals through it to send 3.3v to microcontroller. With the new chip I can disconnect power from the board, but leave turn signals on and the board stays powered through the level shifter. The old part did NOT do this. Is there something I'm missing or just chose wrong chip, and if so do you have recommendation? This is how each chip is pinned out.




vss=gnd (0v)








Josh Christie

  • The CD40109B-Q1 datasheet says:

    Thereare no restrictions on the sequence of application of VDD, VCC, or the input signals.

    The CD4010B-Q1 datasheet does not mention anything similar, and shows in the schematic diagram on p. 2 that there are diodes from the input pins to VDD.

    You have to continue to use the CD40109B-Q1.