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Project Notes

#153 AMS1117 Regulator

Test an AMS1117 3.3V linear regulator

The Build


The AMD1117 is a low drop fixed and adjustable voltage regulator from Advanced Monolithic Systems (AMS). It is similar to “1117” regulators available from a number of manufacturers including UTC and ST. Parts are available for a range of output voltages, including: 1.5V, 1.8V, 2.5V, 2.85V, 3.3V, and 5.0V.

The component I have (obtained from a seller on aliexpress) is marked: AMS1117-3.3 H1518 in a SOT-223 package.

As given in the datasheet:

  • dropout voltage (Vin - Vout): 1.1V typical, 1.3V max
  • Vin max: 15V
  • current limit: 1.1A typical, 1.5A max
  • pin out (from left front): ground, Vout, Vin

Circuit recommendations:

  • 22µF tantalum output capacitor

Some DMM measurements, with a 10kΩ output load:

Vin Iin Vout Iout Pin:Pout
5.09V 2.68mA 3.29V 333µA 13.64mW : 1.1mW

The inefficiency of a linear regulator is clear to see - we’re dissipating 12.74mW in the 1117, far more power than is actually delivered to the load. But they’re convenient!


NB: these diagrams use the custom AMS1117 module fritzing part


The Schematic

Credits and References

About LEAP#153 Power
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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 (IMHO!).

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