MIC5504 3.3V LDO Output Voltage Increases With Load Current—Bad Batch or Circuit Issue?

Hi, I'm using MIC5504 3.3v voltage regulator in my circuit and have been having imense trouble with them. I have indiviually tested 10 of them and they are all exhibiting the same behavior, their output voltage is highly dependet on the output current (not how an LDO should work). My test circuit has 1uF capactiors at input and output then leads giong to a power supply, variable resistor, Ammeter, and a Volt meter. I set my input voltage at 5.0V, then at 0 load, the output voltage is 3.3V, when I start ramping up my current the output voltage increases to around 4.8V at an ouput current of only 140mA, well within the 300mA allowable. Did I just get a bad batch of these voltage regulators?

Specsheet:http://ww1.microchip.com/downloads/en/DeviceDoc/MIC550X.pdf

Thank you all for the valued input!

I assume that the capacitors are low ESR ceramics as specified, directly on the pins, and that you have tied the enable pin high,
cheers,
Richard

I am using low ESR ceramic capacitors, but they are about 1cm of trace from the pins. If that turns out to be the issue then I need to recalibrate how finicky I believe LDOs to be!

Hi, one more issue with ceramic capacitors, they have a VERY strong voltage dependency, more so with the smaller case sizes for the same capacitance and voltage rating, so make sure at the voltage and case size you have, that they meet the specs, go higher than 1uF to be sure. This effect is independent of the temperature rating, you should use X5R or X7R though, for best performance over a wide temperature range.
See this article, https://www.maximintegrated.com/en/app-notes/index.mvp/id/5527
LDO regulators tend to be quite unstable unless you meet all of the manufacturers specifications, the price you pay for a low in-out differential. There are a number of application notes out there about LDO's, it is worth while reading up on the topic.
If you have a scope, monitor the output and see if it is oscillating,
cheers,
Richard