RF telemetry transceiver power circuit design

I have a couple of RF telemetry transceivers that require a power supply.
Specs for them are as follows:
1.8v - 3.6v Supply Voltage.
85mA when transmitting.

I want one to be powered from USB and the other from a 3.6v Lithium Ion AA battery.

I have copied a circuit that I think might work but I don't understand what the capacitors actually do or how you calculate their size for my application.


There are three indication LED's that need to be connected to each transceiver for indication of RX, TX and FAULT.

Can someone point me in the right direction.

From your schematic the IC is a Vcc regulator, generating < 5 V from 5V USB power line. THe capacitors are for filtration, to make sure there are no AC transients of the DC voltages. You can use the values in the schematic, or larger. Connecting 10 uF and 0.1 uF in parallel is used to make sure that low-frequency (10 uF) and high-frequency (0.1 uF) AC components are reduced on the DC lines.

If your RF transceivers are specified for 3.6V DC power supply, you can use the 3.6 V battery or the regulator from your schematic, run from USB. Use a DVM to check that 3.6 V is not exceeded.

You do not indicate where the LEDs are connected. If the transceivers are controlled from the USB, internal circuits should connects then when the module transmits or receives. The FAULT indication must be generated in module controller.