I am using the Bosch BMP280 pressure sensor and the FGPMMOPA6H GPS chip together on a PCB. I am using the reference designs from Adafruit's breakout boards for each chip (found via the product links: BMP280, Ultimate GPS). Both breakout boards use the MIC5225-3.3V regulator, but have slightly different support circuitry.

Here's the regulator circuit for the BMP280: MIC5225-3.3V with BMP280

and here it is for the GPS chip: MIC5225-3.3V with GPS

Since these are going on the same board, I only need to use one voltage regulator for my 3.3V rail. From what I gather from Adafruit's documentation, the enable pin for the BMP280 is always high to keep that sensor on, while the enable pin for the GPS can be switched off to conserve power when the sensor is not needed. Is this correct? Why does the GPS also need a ferrite bead but the pressure sensor does not? Can I keep the ferrite bead in place without it affecting my other loads on the 3.3V rail (such as my ESP32)?


Do not use a 3.3V rail. Use a separate regulator for each circuit. The reason is simple:

Any ripple on the supply will lower the signal/noise ratio of a radio receiver and have a negative impact on receiving the GPS signals. That's why that circuit has that ferrite bead in the supply. The ripple regulation is the better the less load the regulator faces —though LDOs have a minimum load, but that is reached by the GPS receiver easily.

If you are struggling with board space, consider to buy the regulator for the BMP280 in a smaller chip package. (I just saw the MIC5225 is super tiny already.)

You may share the input caps for multiple regulators, but place a small additional input cap near each one.

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