Other Parts Discussed in Thread: TPS62743
First, I'm using a "TPS62231DRY" not a "-Q1" but I couldn't enter that in the dialog box. Not sure if that affects my results, but I wanted to mention it.
In my design I have a TPS62231DRY to regulate 5V -> 1.8V, and I'm measuring ~76% efficiency with currents in the range of 15mA - 25mA, when datasheet says to expect ~82%
and I also have a TPS62237DRY to regulate 5V -> 3.3V, and I'm measuring ~86% efficiency with current in the range of 10mA-11mA, which seems about right
My topology is different between the two in only the output capacitance.
I sized down the inductor to an LQM18PZ2R2MDHD because of size restrictions. This is still 2.2uF and the Q factor should be >>25 based on the datasheet specifications of DCR=0.47 Ohms
5V -> 4.7uF -> TPS6331 ->LQM18P -> 9.1uF total capacitance (76% efficiency)
5V -> 4.7uF -> TPS6337 ->LQM18P -> 11.6uF total capacitance (86% efficiency)
I'm using a Keysight N6705C to supply the 5V and measure current.
When testing the raw current draw I used the N6705C to supply the 3.3V or 1.8V current respectively.
Current was averaged over 30 seconds using the N6705c data logger.
Is an error of 6% allowed deviation from the datasheet spec, or is there something in the design that I failed to consider?