topic Re: RT1170 DAC Reference in i.MX Processors

RT1170 DAC Reference

TM_MI — Wed, 15 Dec 2021 20:55:54 GMT

Hello,

If the DAC output desired is in the recommended range of 0.15V to (1.8V -0.15V) when ADC_VREFH is selected (Rload = 18 k Cload = 50 pF).

My question is if DAC_Vref = ADC_Vrefh, what is the Typical Value of ADC_Vrefh? Datasheet specify a range of 1V to 1.89V.

I am assuming using the recommended settings; ADC_Vref = 1.8 V Typical.

Thanks,

Tarek

Re: RT1170 DAC Reference

kerryzhou — Thu, 16 Dec 2021 06:15:20 GMT

Hi @TM_MI

From the reference manual, we can know:

The only DAC reference option for this chip is VREFH, which uses the ADC_VREFH pin.

ADC on RT1170 Supports only 1.0-1.8V reference (no support for 3V reference)

So, you can connect 1V to 1.89V to the VREFH as the reference voltage.

You can use 1.8V, it's OK.

Wish it helps you!

Best Regards,

Kerry

Re: RT1170 DAC Reference

TM_MI — Thu, 16 Dec 2021 15:34:44 GMT

Hello @kerryzhou ,

Thank you.

For some reason I thought there are two Vref and one is generated internally.

On a relevant subject, the reference manual for I.MX RT1170 includes an Input and an output buffer for the DAC module. Is this the case for all models ? do you know if buffers characteristics listed ?

Regards,

Tarek

Re: RT1170 DAC Reference

kerryzhou — Fri, 17 Dec 2021 03:08:01 GMT

Hi @TM_MI ,

Please check the reference manual for RT1170:

The DAC only can use ADC_VREFH.

In fact, the RT1170 DAC is very simple, for more details, please check the register.

You also can refer to the SDK code:

SDK_2_10_1_MIMXRT1170-EVK\boards\evkmimxrt1170\driver_examples\dac12

Then you will know how to use it.

Best Regards,

Kerry