SN74LVC2G66-Q1: Are its NMOS-body and PMOS-body connected ro GND?

Part Number: SN74LVC2G66-Q1

Hi team, 

1. Are internal NMOS-body and PMOS-body, which make CMOS, connected to GND? (Please see attached figure, yellow marked point)

2. What happen if VCC=0V, VI=5 (or 1A pin) and VO=0V (or 1B pin)? Does internal PMOS turns on irrespective of its control input (or 1C pin)?

I know its recommended does not say its condition, however I would like to understand its operation for start up requirement.


  • 1. In a transmission gate, the NMOS body is typically connected to GND, and the PMOS body, to VCC.

    2. I/O voltages above VCC + 0.5 V violate the absolute maximum ratings, and a current might flow through the ESD protection diodes into VCC, which might turn the device partially on. With a supply below 1.65 V, the behavior is unpredictable.

  • Hi Ochi,

    Thanks for your questions. The issue you are referring to is what we call power off protection. To learn more about this feature that is specified for some of our muxes, please see this video below:

    The SN74LVC2G66-Q1 does not have this feature, so as Clemens mentioned, there might be current flow through the ESD protection diodes that could possibly back power downstream devices and allow the internal logic of the mux to be back powered as well, turning on the switch.

    If you can clarify your requirements for your switch/application (VDD, RON, need for power off protection, leakage, etc.), I can help recommend some devices.