topic Re: PCAL9722 100kOhm matching in Other NXP Products

PCAL9722 100kOhm matching

Fast — Wed, 04 Jun 2025 14:38:43 GMT

Has anyone have an idea what the matching is for 100kOhm pull-up pull-down resistors?

First between pull-up and pull-down on same pin, and between pins?

If we knew what technology it is fabricated on, and size and type of element, we could hazard a guess? +/-10%?

Re: PCAL9722 100kOhm matching

RafaR — Thu, 05 Jun 2025 01:41:10 GMT

Hello Fast

I am starting to work on your case, I will contact you soon.

Re: PCAL9722 100kOhm matching

RafaR — Thu, 05 Jun 2025 22:12:24 GMT

Hello Fast

Well, I'm not sure I fully understand your questions. I'll respond to what I interpreted. Please let me know if you're referring to anything else in your questions.

All information related to the internal pull-ups of PCAL9722 is available under its datasheet:

This internal pull-up/down are “weak”. If you are looking for tight tolerances, general recommendation is to use external “strong” pull-up/down.

I hope this information has helped you, please let me know if you need help with anything else.

Have a great day and best of luck.

Re: PCAL9722 100kOhm matching

Fast — Sat, 07 Jun 2025 13:39:59 GMT

OK RafaR a fixed resistor is so cheap not worth worrying about matching.

Re: PCAL9722 100kOhm matching

Fast — Mon, 09 Jun 2025 09:37:07 GMT

Actually I missed my point; quinary base 5, is an option if pull resistance tolerable; 5 states, VDD, pull to VDD, float, pull to VSS, VSS. as you add ports the resolution increases much faster than trinary base 3. These potential DACs are good for comparator reference and hysteresis control.