Video Design Idea: Build your own laboratory precision voltage reference

-May 24, 2007


Bonnie Baker, senior applications engineer at Texas Instruments and regular EDN columnist, demonstrates a simple way to add DAC functionality to a microcontroller-based system using only an op amp and two passive components.; Bonnie Baker; DAC;; analog design; op amp; video design idea; Mark Thoren, mixed-signal application engineering manager with Linear Technology, demonstrates an amplifier-based circuit design for a relatively inexpensive precision voltage source.; Mark Thoren; amplifier-based circuit design; linear technology; mixed-signal application; precision voltage source; Jim Williams, staff scientist with Linear Technology, explains why PC clocks are invariably wrong, and how engineers can surmount the extreme measurement challenge involved in solving the problem.; cell phones; computer clocks; jim williams; linear technology; nanoamps; quartz crystals; video design idea; EDN Tech Clips deliver technical depth and tutorial design information for engineers involved in analog circuit design, power management, embedded-system design, board-level design, signal integrity, and more.

Designers working on analog circuits in the lab often need accurate voltage sources to test the operation of op amps and other components. A lab power supply isn't a very good choice for such work because most such supplies aren't stable over temperature and time. Of course you could use a 7-decade Kelvin-Varley precision voltage reference although such instruments are relatively expensive and perhaps overkill for the task at hand. Or you can build your own relatively inexpensive 5-decade reference and power it with batteries to ensure that no line noise corrupts the precise output.


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