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Electronics => Projects, Designs, and Technical Stuff => Topic started by: atgeek on November 21, 2016, 01:39:00 am

Title: What ldo for battery project?
Post by: atgeek on November 21, 2016, 01:39:00 am

I need a cheap ldo voltage regulator with low quiescent current for a battery powered project. The input should be in 5-12v range and the output is irrelevant if 5v or 3.3v. Do you know someone?

Title: Re: What ldo for battery project?
Post by: salbayeng on November 21, 2016, 02:11:00 am

I use the TPS76050 (TPS76033 for 3,3v) , its 50mA out, Iq ~ 100uA.

For nanopower applications you might want to look at some nanopower voltage references, many can supply 5v ~ 10mA

One thing to check on the data sheet is how the queiscent current (= ground leg current) changes with load, some parts may add 10% of the load current as quiescent.

If you only want approximately 5v then consider using a depletion mode mosfet , the VGS is -1v so use a 4v low current, low leakage zener diode. The attached figure has a 10k resistor, so Iq = 100uA.  A bigger resistor will mean less Iq at the expense of more temperature drift and worse regulation. With a BSP 149 expect 100mV regulation up to 20mA and < 100mV droput voltage.