What is the current drawn when the U3V70F9 is 1) operating but no load, and 2) in shutdown? I’m using a 7.2V LiPo supply. I see the efficiency graph, but for long term operation the quiescent currents may dominate.
Hi.
A graph of the quiescent current for the U3V70F9 regulator at various input voltages can be found at the bottom of the regulator’s product page. The current draw during shutdown is discussed in the “U3V70F9 connections” section of the same product page.
-Claire
Thanks Clair, I see those now. It looks like operating Iq=~500µA with 9V output and 7.2V input, and sleep Iq=~74 µA under those conditions, dominated by the 100kΩ pullup.
A related question is this. I have been modifying your U1V11F5 step up regulator so that the 100kΩ resistor is a pull-down instead of a pull-up, so the regulator is off by default. That allows my processor to manage orderly power-on for a peripheral device, and also lowers the Iq when the regulator is shut down, ~1µA instead of 30µA. Will I be able to do the same trick with the U3V70F9?
There is an internal pull-down on the EN pin on the U3V70F9’s regulator IC, so you can just remove the pull-up from the board and connect EN to your microcontroller without a pull-down (though adding a pull-down wouldn’t hurt anything). The chip on the U1V11F5 does not have any internal pull resistors on the SHDN pin, so you are right to add a pull-down in that case.
-Claire
Thanks Claire. I’ll order a couple of those and try them out.
In application this is intended to power a satellite transceiver module, so I’ll be looking several aspects in addition to Iq. I see there are three chips on the U3V70Fx module, but for this one you don’t have a schematic posted. Is one available?
We do not release the schematic for our U3V70Fx regulators. If you have some specific questions or concerns about their functionality though, I can try to help.
-Claire
Thanks Claire. I may have further questions later when I have them in hand.