List of MCUs with discreet VBAT pins?

Antypas.Peter · ‎2020-12-02

How do I obtain one? Cube isn't helpful -- this isn't a filter parameter. I need an MCU with built-in backup battery domain for the RTC. I don't want to build anything external and the design must not be capable of powering up the core from the battery, even by accident. The core must remain OFF for months at a time.

waclawek.jan · ‎2020-12-02

There's temporary shortage of some 'F0.

https://community.st.com/s/question/0D53W00000PSUgLSAX/helloare-you-in-trouble-buying-a-stm32f030i-have-trouble-buying-stm32f030-in-the-middle-east-in-most-stores-the-stock-of-stm32f030-is-zerohas-the-production-of-the-series-stopped-or-is-this-deficiency-due-to-the-coronavirus

There's a great deal of compatibility across the whole 'F0 family, so you could perhaps start with https://www.mouser.com/Search/Refine?Keyword=STM32F051C8U and then move down to the 'F030 variants when they become available, hopefully soon.

'G0 may still be a novelty enough so that distributors don't have stock until somebody requests them. There are around 1500 various STM32 models at the market, not counting the extended-temperature and tape-and-reel variants as different models (but the distributors usually do count them as such).

JW

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Peter BENSCH · ‎2020-12-02

There is a general rule: the VBAT domain is always present, but due to package restrictions, the VBAT pin is only available in larger packages, e.g. >32 pins.

The usual method is to select the particular STM32 according to your requirements and review its datasheet. There you will find the package(s) with VBAT pin in the table Pin Definitions in section Pinout and Pin Description.

Good luck!

When your question is answered, please close this topic by choosing Select as Best.

/Peter

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Antypas.Peter · ‎2020-12-02

HUNDREDs of MCUs qualify for this application. That's exactly my problem.

Peter BENSCH · ‎2020-12-02

What would be your requirements beside RTC?

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Antypas.Peter · ‎2020-12-02

2 ADC channels, an i2c bus, a few GPIOs ... pretty much every STM32 has them!

waclawek.jan · ‎2020-12-02

> There is a general rule: the VBAT domain is always present,

Not in 'L0 and 'L1.

JW

Antypas.Peter · ‎2020-12-02

I should also mention that the application is very low complexity and cost sensitive, so M0 would more than suffice.

Peter BENSCH · ‎2020-12-02

Right, L0/L1 don't have it built in, sorry.

But the STM32G030 or STM32F030 would be good choices.

/Peter

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Antypas.Peter · ‎2020-12-02

What's the availability outlook? I searched octopart.com and it seems to be pretty scant for both of these lines. In fact, I can only locate a single F030 with 48pins (F030R8T6) and it's LQFP which is not ideal for size (I would prefer QFN). I can't find any G030s with 48 pins at any of the usual distributors here in the US.

Antypas.Peter · ‎2020-12-02

Looks like G031 is more widely available, so I'll look into that.