Switch mode breadboard supply from a PTH08080

[Ben] wanted a switch mode power supply for his breadboard. He ordered a PTH08080 module which is made by Texas Instruments. The spec sheet would make it a great choice for him, but he was not happy to learn that the pinout doesn’t conform to the 0.1″ spacing used by solderless breadboards. His solution was to make a breakout adapter from some protoboard.

The PTH08080 can source up to 2.25A. It accepts 4.5-18V input and can output 0.9-5.5V. The best part is the efficiency that a switch mode supply achieves compared to linear regulators. This design adds in two capacitors which are suggested in the application circuit from the datasheet (PDF). Notice that there are two headers on the breakout board. One supplies power and ground to the breadboard. The other gives him a place to connect the adjustment resistor used to select the output voltage. This connects between one pin on the PTH08080 and GND. [Ben] plans to upgrade the design by included a precision trimpot for easy output voltage adjustments.

Comments

  1. crenn says:

    Looks nice, I’ll have to remember this design when I go prototyping again

  2. rick says:

    i have been using these switch mode dc converters for a few months now as a trickle charger for my desulfator circuit. they are extremely easy to set up and very efficent. i power mune from old laptop power supplies and set the voltage for 13.50vdc and it keeps the battery floated while desulfating.

    • Tron9000 says:

      agreed, they are pretty damn useful! I’ve used these to MASSIVELY reduce a giant PSU rack design to just a single circuit board.

      Someone at TI was having a “good-day” when they made these!

  3. Sven says:

    I have used lots and lots of the KIS-3R33S module, a similar buck converter that’s available used but in good condition from china. I have ordered about 150 of them and only come across a couple that were broken.

  4. Grant says:

    TI has a few similar switching regulators that work quite nice. They default to 5v output if you don’t have the adjustment resistor connected.

    And of course, TI is AWESOME for sending out free samples of their parts – this regulator costs $5.73 in quantity, and they’ll send you a couple through fedex for free with no hastle.

  5. cde says:

    A review on the TI website shows that this supply has a 21 MA transient current draw when not powering any load. I’m assuming that is with the enable/interrupt pin not grounded, but even then, that is a hell of a draw for battery power projects, quickly kill a battery if not controlled.

    Can anyone confirm?

  6. ftorama says:

    With a bit of pin bending, you can also solder it directly to a 3-pin connector and use it as a 78xx replacement.

    You simply need to tie inhibit to GND with a small wire and put the configuration resistor on side of the module.

  7. rick says:

    i meant to ask anyone, after pkaying witg a fee of these what style pinout is this package? it doesnt even line up with standard through hole protoboards.

  8. bfhben says:

    The row of 2 pins are 0.1″ spaced, though the pins are too fat. The center of the row of 3 is also aligned by 0.1″ to the row of two. The outer two however are approximate 0.15″ from the center pin instead of 0.1″. The datasheet will give you exacts.

  9. Az says:

    TI makes some very impressive DC-DC converters and related bits.
    If you’re like me, once you’ve worked with one or two, you wind up spotting their relatives on all kinds of kit.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s