Fork me on GitHub

Project Notes

#152 LD1117 Regulator

Test an LD1117 3.3V linear regulator

The Build


The LD1117 is a low drop fixed and adjustable voltage regulator, available from a number of manufacturers including UTC and ST. Parts are available for a range of output voltages, including: 1.2V, 1.5V, 1.8V, 2.5V, 2.85V, 3.0V, 3.3V, 3.6V, 5.0V, and ADJ.

The component I have is marked: UTC LD1117AL 33D010HT5

Although I can’t find a datasheet that matches these markings exactly, I figure:

  • A = 1A
  • L = lead free
  • 33 = 3.3V
  • D? = pin out is (from left front): Vin, Ground, Vout

Note that the LD1117A by ST has a different pin configuration for the TO220 package. From pin 1 left front: Ground, Vout, Vin.

Some DMM measurements, with a 10kΩ output load:

Vin Iin Vout Iout Pin:Pout
5.10V 2.47mA 3.30V 329µA 12.6mW : 1.09mW

The inefficiency of a linear regulator is clear to see - we’re dissipating 11.51mW in the 1117, far more power than is actually delivered to the load. But they’re convenient!



The Schematic

The Build

Credits and References

About LEAP#152 Power
Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is my personal collection of electronics projects, usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting (IMHO!).

The projects are usually inspired by things found wild on the net, or ideas from the sources such as:

Feel free to borrow liberally, and if you spot any issues do let me know. See the individual projects for credits where due. There are even now a few projects contributed by others - send your own over in a pull request if you would also like to add to this collection.