Reg. VSUP Voltage, Internal Resistive Divider

[mohanvustepalle]

I am using 'MC912ZVL32' series. Need to monitor the voltage range from 9 to 16V. For that configured 10 bit ADC with ref voltage as 5V but unable to find out the internal resistive divider of VSUP to ADC.

Below are my observed values at different voltages

VBATT Voltage     VSUP voltage    ADC value

   9V                             7.82 V               201

   12V                           11.2 V               271

   16V                            15.6V              367.

Based on the above values the relation differs for the voltage and unable to find out the relation in the Reference manual.

It just mentioned as

Kindly let me know if any one knows the Internal resistive divider value.

Thanks,

Mohan V

[RadekS]

Hi Mohan,

The Internal resistive divider ratio value is specified in Appendix F BATS Electrical Specifications of RM.

The Pin Input Divider Ratio = 9 ( RatioVSUP = VSUP / VADC; with 5.5V < VSUP < 29 V).

The Absolute Error on this divider is typically +/-2% and maximum +/-5%.

Note: The Pin Input Divider Ratio will be 17 when we select 3.3V VDDX output voltage – available only for S12ZVL128/64 derivatives.

I hope it helps you.

Have a great day,
Radek

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