AVR DB: Microcontroller internal opamp - input bias current?

[Faranight]

Hello.

The AVR32DB32 microcontroller comes with a few built-in signal-conditioning operational amplifiers.
I've checked the datasheet, and chapter 35 on page 525 describes the opamp, chapter 39.5.12 on page 615 shows the opamp AC characteristics while chapter 40.1 shows the opamp charts.
But can't seem to find any information on the input bias current for the built-in opamps. Am I missing something or is this parameter just not listed (why?)?
I need it to calculate an error margin and resistor values for a voltage divider.

https://ww1.microchip.com/downloads/aemDocuments/documents/MCU08/ProductDocuments/DataSheets/AVR32DB28-32-48-DataSheet-DS40002301A.pdf

[magic]

My guess:

"It's CMOS, so input bias is insignificant for applications this dodgy thing could be adequate for".
"If you need to ask, this isn't a device for you".


Yeah, it would be kind of them if they could at least provide a ballpark "typical" spec.
But then again, look at MCP6002, which is a "real" opamp from the same guys. No guaranteed maximum at all

[Faranight]

Maybe it's because the opamp input pin is multiplexed with other functionality available on that pin.
So, whatever current the opamp is draining is insignificant to the leakage on other parts of the input?
And the datasheet does state a spec about current leakage on I/O pins (< 5nA) though it applies for pins in high-impedance state only.
I'm not sure.

[Dabbot]

In the datasheet you linked, search for "Input Leakage Current":

<5na typical, and "...valid also when the pin is used as an input to an enabled analog peripheral"

[Faranight]

Oh, thanks. I missed the "valid also when the pin is used as an input to an enabled analog peripheral" part.
Solved then.

[harerod]

Oh, thanks. I missed the "valid also when the pin is used as an input to an enabled analog peripheral" part.
Solved then.

Don't beat yourself up. Although I knew that I was looking for that specific information, I overlooked it last night. I expected and wanted to give exactly that answer.

[rant]
I had one major project on the AVR32AP, back in 2008. Critical omissions in the datasheet of that then new product led to several redesigns. We started out with 6 layers and ended with 12 layers. One crucial problem was the power supply during peak performance. MCU was fine with basic hardware tests, but tended to crash when the Linux application went full power.
Atmel pulled the same stunt in 2004 with the AT91RM9200.
I hate eventually seeing errata that burned thousands of Euros of my money.
Looking back at those two old Atmel components, I can only say that STM32 is gold by comparison.
[/rant]