nPM2100 passthrough

RE: nPM2100 passthrough

charlesmarseille — Thu, 29 Jan 2026 12:58:43 GMT

I stumbled upon this conclusion also. Indeed, the docs are not very clear about the main functionnality of the device.
We had to put an external LDO to manage the VBAT>VOUT situation.
A simple one liner in the docs would fix all these misunderstandings and testing time for customers.

RE: nPM2100 passthrough

Asbjørn — Tue, 17 Jun 2025 16:31:17 GMT

Hello,

I'd recommend you to set up your own DevZone ticket to follow your concerns and behaviour and then link to this one if you'd like.

Best regards

Asbjørn

RE: nPM2100 passthrough

Audun — Tue, 17 Jun 2025 07:42:06 GMT

Hi Nick_RA

>I guess a better was to phrase my question: Is the switching regulator BOOST only rather than BUCK/BOOST?

Yes, the nPM2100 regulator is a BOOST only. When VOUT is set to lower than VBAT, it will pass VBAT directly to VOUT without regulation.

As you mention, there is an LDO available also, which would be the only way for nPM2100 to reduce VBAT voltage.

Best regards,

Audun

RE: nPM2100 passthrough

armadillonoah — Fri, 13 Jun 2025 18:40:27 GMT

I'm here with the same issue. When I put VSET to 1.8V with a 3.0V Battery or VEXT.... I get 3V.

Is this a bug? Can it be fixed?

RE: nPM2100 passthrough

Nick_RA — Thu, 12 Jun 2025 10:03:38 GMT

I guess a better was to phrase my question: Is the switching regulator BOOST only rather than BUCK/BOOST?

When I set up the EV kit with PowerUP I couldn't set Vout less than Vbatt. I initially thought the EV kit may have been faulty but I bought a 2nd one to verify.

By the way, I don't mean using the LDO to drop VOUT down to 1.8v when using 3V battery.

RE: nPM2100 passthrough

Asbjørn — Thu, 12 Jun 2025 09:52:59 GMT

Hello Nick,

For the BOOST pass-through mode, Vbat needs to be 100mV above the target Vout.

You can run the BOOST from 3V and have Vout set to 1.8V.

Maybe I'm misunderstanding you here now, so let me know if this wasn't the question you asked.

Best regards

Asbjørn