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KiwiSDR Voltage Range
5V PSUs don't always deliver exactly 5.0 volts. Quickstart says the Beagle will power down by 4.75V, but which upper limit shouldn't be exceeded? I have one (originally supplied with the RF Space NetSDR) which measures 5.17V with my DVM.
edited April 15
Short answer: 5V +/- 0.25V.
That's according to the BeagleBone Black spec.
The 5V DC in goes from the Kiwi board first to the Beagle power management IC (PMIC) where it is tested for under/over-voltage and switched. The switched 5V returns to the Kiwi board and is regulated down to 1.8 and 1.0V. It also powers the regulators on the Beagle. Kiwi 3.3V is taken from regulators on the Beagle.
There is some voltage drop along this path given that over 1A is being pulled at 5V. The common mode choke on the Kiwi board drops the voltage a bit. So a more valid measurement is at the header pin marked 5VE (E for external).
If my bench power supply were working I'd try some experiments. I have some Beagles now that have dead Ethernet PHY chips and so are basically useless and perfect for some over-voltage experiments.
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