LPC84x ADC current?

[mike_hackett]

LPC84x part.  Maybe ADC curent specified wrong

Hi.

Just checking my design for the current it takes using the LPC84x part.

There is a large current spike I can't account for when I do some A2D measurements.

In data sheet LPC84x (Rev. 2.0 — 6 November 2019)  on page 54, the current draw for vthe A2D when in full active mode is specified 79uA (@12MHz).

This is the same current as in all modes of operation, low power, full mode etc (to within 1uA) .

A s a comparsion the LPC82x takes 1990uA in full mode.  Which is the magnitude of the unknown current spike.

Is the LPC84x ADC 79uA in full mode, or is it closer to 1990uA as specified for the LP82x.

Thanks

[xiangjun_rong]

Hi, Mike,

I have checked the data sheet of both LPC84x and 82x, the ADC current of LPC84x is about 190uA in 30MHz ADC clock, the ADC current of LPC82x is about 80uA in 15MHz ADC clock.

Regarding the current spike you observed for the ADC current, I suppose that you connect a capacitor to the VDDA pin, which leads to a current spike in power-up stage.

Hope it can help you

BR

XiangJun rong