I'm hoping I can ask for some advice on how to best control power to my Adafruit Ultimate GPS Breakout using an N-channel MOSFET.
In the past, I've used the FQP30N06L N-channel logic-level MOSFET to turn power to the GPS on and off. This has been when I had the MOSFET's drain pin connected directly to my 4.2-5V battery. However, as I'm now looking to power my circuit from a 7.4-11.1V battery, I'd like to power the GPS directly from the 3V pin of my Adafruit Pro Trinket 3V. The Ultimate GPS notes that it has a minimum operating voltage of 3.0 V and a current draw of ~25 mA and the Pro Trinket's regulator can output a maximum of 150 mA. When I connect the GPS directly to the Trinket's 3V/GND pins it works fine. However, when I add the MOSFET and connect the circuit as shown below, my Pro Trinket enters a reboot loop as soon as the MOSFET is enabled. I have on hand two different N-channel MOSFETS: the FQP30N06L and the TN0702. I've observed the issue with both.
From researching this issue, it appears that the reset loop problem may be due to the voltage drop experienced by the Pro Trinket when the MOSFET is enabled and power is supplied to the Ultimate GPS. It sounds like the voltage drop may be triggering the ATmega328's brown-out detection and reseting the microcontroller.
When I replace the Adafruit Pro Trinket 3V with a SparkFun Pro Mini 3.3V this problem goes away. Could this perhaps be explained by the differences between the Pro Trinket's MIC5225 and the Pro Mini's MIC5205 regulator? It looks like the Trinket's 5225 has on average about twice the dropout voltage than that of the Pro Mini's 5205, though I'm unsure if this would be the cause of the problem.
Given that I'd like to continue using the Pro Trinket, I'm wondering how to best tackle this issue. Possible solutions I've seen involve slowing the power on/off cycles of the GPS, adding a capacitor to buffer the spike and/or using a high-side P-MOSFET.
If anyone may have any suggestions or pointers on what I might be doing wrong, I'd greatly appreciate it!