Controlling ADC (on/off) with microcontroller

Thread Starter

mostafakibrahim

Joined Jun 24, 2022
2
Hello,
I'm designing a PCB and I wanted to turn off/on ADC(ADS1120) using microcontroller (SAMD21G). The ADC has two power inputs, 3.3V analog and 3.3V digital. The 3.3V analog is connected to an LDO that has an enable pin which is connected to one of SAMD21G pins, so that power pin I can turn on and off. For the 3.3V digital however, I can't turn on and off the LDO as it connects to other components. So, I was thinking about using two MOSFETS one PMOS connected to 3.3V digital with its gate connected to the drain of an NMOS (with gate connected to pin of SAMD21G) that way it acts as kind of an enable. Also thought about using a tri-state buffer with enable pin (connected to SAMD21G), not sure if that is a good idea though. Any other ways I could do that, and which would be the best way? Thanks in advance!
 

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ronsimpson

Joined Oct 7, 2019
2,161
The big question. why? To save power?

The digital part, in power down mode = 0.3uA. Adding your power down circuit will probably add more current than that.
The analog part, disable the PGA and save power. (and) In power down mode 0.1uA.
 

Thread Starter

mostafakibrahim

Joined Jun 24, 2022
2
Yea, main reason was to save power. But I realized as you mentioned, turning off the AC power already saves a lot of power. I also didn't know about the power down mode, will check that out. But if that wasn't the case and I wanted to control it using the microcontroller, what method should I use?
 
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