Monthly Archives: February 2013

Switch Mode Regulator Drop In Replacement for LM7805

I have completed the design, layout, assembly and initial testing of a switch mode regulator that is a drop in replacement for an overheating LM7805.  It includes all the capacitors on the module.  The module is only a few millimeters wider than a TO-220 package.  With 12V in and 0.5A load current a LM7805 needs a fairly substantial heatsink to keep the device from reaching over temperature cutoff.  The new module can supply 1A continuously with 15V input without overheating.  The back of the module gets noticeably hot but does not burn you when you touch it.

What needs to be done is more testing and some documentation before I’ll offer the part for sale from this web site.  If you are interested in an evaluation module, send an email and I send you a module for test.  I will also offer a 3.3V version.

• Drop-in replacement of 3-terminal LM7805 or equivalent linear voltage regulator.
• Guaranteed 1A output current
• Wide input voltage range up to 7V to 17V
• High efficiency, greater than 70% for loads greater than 1mA, peak efficiency achieved of 90% at 300mA load current.
• Thermal shutdown and current limit protection
• Breadboard friendly
• Board dimensions are 0.51″ x 0.75″ or 12.9mm x 19mm excluding pins. With pins 1.09″ or 27.75mm.
• Definitely no heatsink required.
• All components are mounted on one side of the PCB
• Highest component is the plastic of the connector at 0.15″, Next highest is the inductor at 0.121″ including the thickness of the PCB
• Available with straight or right angled pins.
• Weighs only 0.04 Ounce or 1.3g, ideal for RC model aircraft or quadcopters
• Can drive inductive loads such as DC motors.
• 2.2MHz Switching Frequency

The price is $6-95 in singles with discounts starting from 10 pieces.  If all goes well stocking quantities will be available by next week.


Size comparison PSU2-5 with LM7805 in TO-220 Package

Size comparison PSU2-5 with LM7805 in TO-220 Package

Shipping Cost

After fighting with the shipping calculator we now have new shipping rates for USPS First Class mail.  The shipping calculator refuses to offer First Class mail as an option so we added a table based shipping cost calculator that should fix this issue.  For people in the UK, the shipping calculator would routinely produce $50 as a shipping charge and this is ridiculous since our most expensive item is only $59-95.  We now offer world wide shipping for $6-95.

I hope the new shipping rates make shopping a pleasurable experience.


New Products

We are always looking for new products that solve real problems and are easy to use and master.  We are almost done transferring the manufacturing of our existing products to the new equipment.  This is a big task because all the pick and place programs were re-written on an unfamiliar machine.  At the same time we built stock so we can spend time on the machine programming the production of new designs without having to stop midway and build some board because stock is running low.

The first time you build a board on a new machine there is a lot of setting up to do.  You have to transfer the CAD data to the machine so you know where to place the parts.  Then you have to mount the reel containing a part on the feeder, tell the machine that the feeder exists and where it can find the part.  This goes quickly for one or two new parts but it gets tedious to do it for every part used in all the designs.  You also have to figure out how the tape goes into the feeder, where the cover tape goes etc.  Once you know, the next time is easier and by the filth one, it is easy.  Then you end up learning how the matrix trays work and the optical alignment.  Everything takes a lot of time the first time round.  One of the strange behaviors of this machine is how it picks up parts from the matrix trays.  It starts from the last position and ‘advances’ to the first position.  My first tray was partially used so I carefully moved the parts to the start of the tray just to discover that the machine starts from the side that I had just emptied out.  So I moved all fifty parts back to the other end of the tray.  What a waste of time.  Now, after having built panels of everything we sell we can move on to new designs.

The first new design is a small switch mode voltage regulator to fit the footprint of a standard TO-220 LM7805 type linear regulator.  When the supply voltage is a little high and the load current more than a few milliamps then the linear regulators run very hot with small heatsinks.  There are switching regulators of this type on the market but the suffer from two problems:  Most need external capacitors and are very expensive, around $10 each.  The new design has all the capacitors on board so you can remove and overheating linear regulator and drop this one in its place without having to find a place to hide a few external capacitors.  The price is going to be less than $6 in singles.

Watch this space.