DESIGN VIEW is the summary of the complete DESIGN SOLUTION contributed article, which begins on Page 2.
One, zero, one, zero, one, zero... repeat forever. Building a clock should be one of the simplest engineering design challenges. And it is, unless you need it to be small, stable, and tunable. Traditional approaches involve a 555-type timer, or perhaps a comparator with a handful of discrete components. But these solutions consume board space, have limited stability over voltage and temperature, and yield poor accuracy beyond a few hundred kilohertz.
Resonant-element oscillators (crystals, ceramic resonators) boast superior accuracy and stability but are less robust. They're also not adjustable. However, a new class of device, the resistor-programmable oscillator (RPO), combines excellent accuracy and linearity, a small footprint, low power, and the ability to be swept over a wide frequency range. It uses only two components (three if you count the supply bypass capacitor): a tiny SOT-23 IC and a timing (set) resistor. They are the only oscillator ICs that can accurately generate an infinitely variable square wave without using a crystal, ceramic resonator, or external clock reference.
Viewed from the outside, the RPO is deceptively simple. Behind the curtain, though, a proprietary internal feedback loop works to maintain a linear relationship between RSET and the output frequency. Plus, there's a typical temperature coefficient of only 40 ppm/°C and stability over the supply-voltage range of 0.05%/V.
The article highlights the benefits of the RPO and discusses applications where it enhances design flexibility and performance. Some of these applications include timing circuits, synchronized power regulation (via a multiphase clock), and filter circuits. Tips on getting the most out of the RPO are provided as well.
Full article begins on Page 2