STM32F070RBT6 RESET CONDITION

[kemrek]

We work with STM32F070RBT6 . There is an internal POR/PDR controller in microcontroller but it seems to be active when VDD below 1.8V according to the product datasheet but the operating voltage seems between 2.4V to 3.6 V.

In Run Mode, If the input voltage VDD fall below 2.4V but not below VDR detect level (1.8.. 2V), in other words between (2.4 V and 2V) what will be happen? 

[Peter BENSCH]

Welcome @kemrek, to the community!

POR/PDR are always active, i.e. cannot be deactivated. As can be found in RM0360, section 6.2.1., these modules ensure proper operation down to the threshold voltage. The threshold voltage in turn is specified in the data sheet, Table 22, whereby different values apply for falling and rising edge due to the hysteresis.

Hope that answers your question?

Regards
/Peter

[kemrek]

Dear Peter,

in RM0360 in page 76

* The STM32F030/STM32F070 devices require a 2.4 V - 3.6 V operating supply voltage (VDD) and a 2.4 V - 3.6 V analog supply voltage (VDDA) 

so i understand minimum working voltage is 2.4V for STM32F070 it is above 2 V (PDR limit) and also in data sheet PDR is minimum 1.8V (according to table 22)

should we understand minimum working level is 1.8V for these modules?

we want to be sure that the device will work between PDR limit and 2.4V.. 

[Peter BENSCH]

OK, now I understand the background to the question. It should be mentioned that the STM32F0x0 belong to the so-called Value Line, where some parameters are broader or completely missing compared to more powerful families. POR/PDR were developed for the more powerful families, whose parameters are the same in this specific case. Nevertheless, the guaranteed voltage range for the STM32F070 is 2.4V-3.6V. So even if POR/PDR is supposed to safeguard the function from 2V, a supply of <2.4V is still not a guaranteed operating range.

It is therefore quite possible that the STM32F070 will work in this voltage range - however, no guarantee is given for this.

Regards
/Peter