DS90UB9722-Q1: ADC ExtVol0/1

d_zero

Dear Team,

in DS is stated if ADC on DS90UB9722-Q1 measure voltages up to 1.207V.

Our questions is:

-> if VDDIO is connected to 1.8V then ADC input ( GPIO0 or GPIO1) is tolerant up to 1.8V but it will measure the same value for 1.207V and 1.8V is that correct?

-> if VDDIO is connected to 3.3V then ADC input ( GPIO0 or GPIO1) is tolerant up to 3.3V but it will measure the same value for 1.207V and 3.3V is that correct?

Best Regards,

over 1 year ago

0 Glenn Uranga over 1 year ago

TI__Genius 16220 points

Hi David,

The pin will always see a voltage up to 1.207V. If you would want to measure a 1.8V for example, an external voltage divider would be needed to bring down the 1.8 or 3.3V below 1.207 threshold.

If you use a 10K and 10K divider on 1.8V then it would drop to 0.9V. This is within the 1.207V and 0.9V would indicate it's detecting the 1.8V on that pin.

Glenn

0 d_zero over 1 year ago in reply to Glenn Uranga

Genius 5015 points

HI Glenn,

we don't need to measure the 1.8V but only 1.2V , but in some cases the voltage that can be seen on the pin is 1.8V, will this damage the pin of VDDIO=1.8V?

it is for the TPS2H160 current sense, in normal operation the max voltage is 4V bit if fault occurs it is 6.5V

we use resistor divider to bring down the 4V to 1.2V -> meaning 6.5V is also brought down to 1.8V but we don't need to measure it but the adc pin only needs to survive it.