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I'm looking for a low drop voltage regulator to use in a 600mA – 1000mA (peak) 3.3v system that can be powered either through a singe-cell LiPol battery or USB (so a max drop of ~0.4V).

So far the AP2112K seems like a good choice and is moderately priced, but I would like to know of alternatives. This is intended for hobbyist usage, so industrial-level quality is not required.

Any recommendations?

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closed as off-topic by brhans, Ignacio Vazquez-Abrams, Daniel Grillo, Matt Young, Ricardo Jul 22 '15 at 18:51

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    \$\begingroup\$ Don't forget that the actual voltage of a LiPol battery will vary from about 4.2 v at full charge down to ~2.7V when discharged. You will not be able to maintain a 3.3V output with just an LDO. A buck/boost switching regulator maybe what you need. Or let the LDO go into saturation and the output voltage drop to 2.7V and design your circuit appropriately. You may be able to get away without a regulator at all. kevin \$\endgroup\$ – Kevin White Jul 22 '15 at 18:25
  • \$\begingroup\$ "Chinese-manufactured sold in eBay with free shipping" is ALWAYS a bad idea, whether hobbyist or commercial. \$\endgroup\$ – Matt Young Jul 22 '15 at 18:50
  • \$\begingroup\$ I don't understand the "off-topic" vote, but I've tried to modify the original question. The main focus is on alternatives to regulate LiPol to 3.3v. \$\endgroup\$ – Hugo Sereno Ferreira Jul 22 '15 at 18:58
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Texas Instruments has a great step-down DC/DC converter which operates from a Single Li-Ion Cell (3 V to 5.5 V). It is the LM3281.

Main features:

  • Operates from a Single Li-Ion Cell (3 V to 5.5 V)
  • 6-MHz (typ.) PWM Switching Frequency
  • Fixed Output Voltage: 3.3 V
  • Up to 1.2-A Maximum Load Capability
  • High Efficiency: 94% (typ.) with 3.8-V VIN at 300 mA
  • Analog Bypass: 60-mV (typ.) Drop-Out at 600 mA

enter image description here


It is 0.861USD at a quantity of 10 at DigiKey or you can give a try and order samples from TI with an appropriate e-mail address.

A disadvtage in your case:

  • The only available packaging is BGA, but it has only six pins in two row on both side of the IC. So it is not impossible to solder it with a hot air soldering iron.

    enter image description here

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