Dynamically changing supply voltage

[embedded_ee]

I have a follow-up to this question: devzone.nordicsemi.com/.../

We are interested in dynamically changing the supply voltage because our space-constrained design requires it. Specifically, extra board area for level translation components is not available.

We would greatly appreciate if you could please provide specifications to guide our implementation of dynamically changing the supply voltage. In particular, the most valuable spec would be a slew rate spec for the supply voltage. Clearly, in battery-powered systems, there is no problem as the battery voltage changes during discharge -- this is an example that dynamic supply voltage change is clearly possible.

In addition to a slew rate spec, is it possible to please provide a datasheet(s) for the internal LDOs?

If there are specific hardware issues / concerns that this approach would cause, please explain what they are; it would be helpful for us to understand them so that we can figure out a way to address these issues.

EDIT: This question: devzone.nordicsemi.com/.../ mentions testing supply ripple and the effect on radio sensitivity. Is this where the suggested 100mV-pp value comes from? If the only adverse effect from slewing the supply voltage is on radio performance, we can work around this in our application.

Thanks! Jon

[Asbjørn]

This information is not available in the nRF24LU1+ documentation. The slew rate isn't defined, but worst case if you change between voltages is that you will reset the chip. How fast you can change it is not a number we have available. I don't see any issues with what you guys are planning. If you are planning on sudden changes, then you would have to expect a reset on the chip.

The 100 mV values are tests that we did on the radio interface if you have noise on the power supply. The performance of the chip will be the same if it runs at 2.0 V or 3.3 V as internal regulators provide the internal supply.

[embedded_ee]

Thank you!