Input Current

Hi Gene,

Can you tell me which databook and which section to look in for this?  I have many of our old databooks here (unfortunately not all of them though).  I looked through the LV book I have but didn't see anything like this.

In an LV family characterization packet, I did find a plot very similar to what you show, but it's for Icc vs Vin, not Iin vs Vin (and the peak current was 80 uA).  This makes perfect sense since the input to a CMOS part usually goes to a single inverter's input, which is the circuit below (borrowed from https://en.wikipedia.org/wiki/CMOS):

The reason the curve has that inverted V appearance is because the current flows from Vdd to Vss through both FETs only when both FETs are turned on - when A is at its midpoint value.  As A approaches either end it shuts off one of the FETS and effectively stops the current flow.

The Iin vs Vin plot I saw showed a steady decrease, with a max of ~22 uA at 0V and 0 at 3V.  This is likely due to leakage on a protection diode.

I wish I could say why we don't have these curves in the datasheets, but all I can say for certain is that we don't.  If you need the information for a particular application, I can schedule some time to test the parts for you.

I don't have access to old books anymore. The Iin vs Vin plot would not match the spec sheet, since it says Imax=1uA at 0 and Vcc.

It would really be helpful to see a plot of Iin vs Vin for sn74lv14a! If you could provide that I would be very greatful.

Thanks

Hi Gene ,

The input current vs input voltage I could find for the SN74LVC family is as shown below. This would be along similar lines for SN74LV family since the inputs are CMOS structures which have high input impedance .Input voltage going negative is not recommended as the internal diodes conduct and beyond the abs max specified -20mA it can harm device by damaging the ESD(electro static diode) structure.

Shreyas,

Please don't feel you have to respond.
There is nothing shown and no one said anything about negative input voltage.

Sorry ,Gene, I tried to put the graph but somehow it doesn't show up in the post .  I will try this again here hopefully it comes out well .

Gene,

I can get into the lab next week to do a plot of this for you (definitely).  If we're lucky I can find time this week.  Can you tell me about the application that you are putting this part into?

Emrys,

I really appreciate you getting this information for me.

Thanks!

Gene

Emrys,

I am hoping you didn't forget about me. Is it likely I will see this information soon? I have to move on this

part shortly, and I would really appreciate having that information.

Thanks!

Regards,

Gene