SN74LVC1G125: Input to VCC circuitry/resistive property.

Hi Petrone,

You can see if a device has any internal diode in the circuitry by reading through this FAQ: 

1. [FAQ] Can the input voltage (Vi) to my logic device be higher than the supply voltage (Vcc)? \

For input resistance refer to this FAQ; 

1. [FAQ] What is the impedance of the device's input pin? Is it CMOS or bipolar device?

Hello Albert, 

I've looked at the application note and the LVC does not seem to have a positive clamp diode ( the LV family does) and we're seeing characteristics as if the LVC series also has the positive clamp diode. We have 20 of these buffers in parallel, which is giving us a 30k resistance ( forward bias of ~ 600kohm per /device). Figure 3 in this application note. 

Is this expected from the LVC series? 

LVC does not have positive clamping diodes.

A diode does not have a constant resistance.

Please specify how exactly you are observing or measuring the resistance.

Hello Clemens, 

When measuring resistance from (DMM+ probe)  VIN and GND ( Connected together in our configuration to VCC (DMM- probe)  of 20 of these devices in parallel we see a constant ~30kOHM resistance. However, when we swap the probe (DMM+ on VVCC and DMM-* on VIN/GND)  we measure an open circuit. Almost diode "like" behavior..