I’m working on a low energy device consisting of a couple of IC’s. What is confusing to me is the following, All ICs has a vcc supply range of 1.7 to 3.6V and most of the time the current reading is given @3.3v supply. Chasing the most efficient design what is actually better running at the bare minimum supply ( assuming the internal LDOs has less power to dissipate ) or run at 3.3v?
I have tried to read if there is reduced performance at lower voltage but it is not apparent. The other question that then comes of the back of the previous question, if all ICs has a supply range 1.7 to 3.6 and all IO pins is rated to 3.3v can I run some ICs at 1.8v and other at 3.3v without effecting let’s say SPI or I2C communication ?
These are the ICs MCU infocenter.nordicsemi.com/pdf/nRF52832_PS_v1.4.pdf Radio semtech.com/uploads/documents/sx1272.pdf GPS u-blox.com/en/product/sam-m8q-module. I found a new MPPT DC reg from ST this one. st.com/content/st_com/en/products/power-management/… The idea is to run the MCU from the 1.7v LDO and only when Battery charge is sufficient enable the 3.3 VDO that feeds the rest of the system. My concern would be the UART and SPI coms between GPS and Radio IC... and MCU
Any advice is appreciated