Nuts & Volts - September 2006

READER FEEDBACK Continued from page 6

proved problematic. It was then that I discovered the handy Texas Instruments (formerly Power Trends) PT5101 integrated switching regulator. This little module (about one inch square) is a virtual drop-in replacement for the 7805 in most circuits, but is far more efficient ( 90+ percent) due to its switch-mode (versus linear) operation. It can deliver + 5 volts at up to 1 ampere of output current with input voltages ranging anywhere from 9 to 38 volts, and all this

PLANS/KITS/ SCHEMATICS

with no heatsink! The only external component required is a 100 μF capacitor from the output pin to ground, which is a common requirement for many regulators, anyway. It is available in vertical (N suffix) and horizontal (A suffix) through-hole versions, as well as surface mount (C suffix). The only downside? It costs about $12 from Digi-Key. But for many of your readers' applications, it might be just the ticket! It is now my first choice when I need

on-board voltage regulation. By the way, there are other output voltages available too, such as + 3. 3, + 9, + 12, and - 12 (yes, inverting), as well as boost versions (the PT504x series) that can generate your other on-board voltage needs with a + 5 volt supply as input! These devices are a great alternative to a heatsink in many designs. Thank you for the opportunity to share my experience with your readers.