topic Re: LPC82x Internal Voltage Ref to ADC? in LPC Microcontrollers

LPC82x Internal Voltage Ref to ADC?

mwp_nxp — Tue, 17 Jan 2023 03:18:47 GMT

Hi all,

(I thought I posted this question yesterday, but it seem to have disappeared. Weird.)

The LPC82x has an internal 0.9v voltage reference that the doc's state can be used as a reference input to the comparator peripheral.

Is it possible for this reference to be routed to an ADC input?

I ideally would like to be able to measure it with the ADC, so I can then determine the VREFP (and so VDD) voltages. I have done this with MKL03/05 in the past.

Thankyou!

Re: LPC82x Internal Voltage Ref to ADC?

RaRo — Tue, 17 Jan 2023 18:50:44 GMT

Hello @mwp_nxp,

Unfortunately, there is not an option for routing the 0.9V internal bandgap reference voltage to an ADC input channel for the LPC84x.

As a recommendation, you could try reading the following Application Notes:

AN5250. How to Increase the Analog-to-Digital Converter Accuracy in an Application
AN4373. Cookbook for SAR ADC Measurements
AN13102. How to Get Best ADC Accuracy for LPC800.

They might be useful.

Best regards, Raul.