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Project Notes

#152 LD1117 Regulator

Test an LD1117 3.3V linear regulator

The Build

Notes

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!

Construction

Breadboard

The Schematic

The Build

Credits and References

About LEAP#152 Power

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

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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.

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