Widlar
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Widlar
A tribute to analogue design master, Bob Widlar
The Fairchild μA723 voltage regulator is not at first sight a particularly exciting integrated circuit. Designed by the legendary Bob Widlar and released in 1967*, it should have followed the majority of its contemporaries and faded from supplier catalogues and parts lists during the 1970s as it was superseded by more capable devices. Instead it has persisted, and five decades later it can still be found in the product lists of several semiconductor companies.
This project is a tribute to the chip's designer and its legacy.
* After the release of our project, doubt has been cast on whether Widlar has actually designed the μA723. Wikipedia has more.
Widlar was project #21 of the Booldport Club.
What’s included
1x μA723, TI UA723CDR
1x NPN BJT TO-220, Fairchild BD239BTU
5x 470Ω resistor 250mW, Multicomp MCF 0.25W 470
5x 4.3KΩ resistor 500mW, RS PRO739-8809
5x 1.5KΩ resistor 500mW, RS PRO739-8767
3x 10KΩ resistor 250mW, Multicomp MCF 0.25W 10K
1x 10Ω resistor 600mW, Multicomp MCMF006FF100JA50
1x 3Ω resistor 600mW, Vishay MBB02070C3008FCT00
1x 10KΩ trimmer, Bourns 3306W-1-103
2x 100pF ceramic capacitor, Suntan TS15001H101KSBSA0R
2x 470pF ceramic capacitor, Suntan TS15001H471KSBPA0R
1x Lovely PCB
Assembly and usage
Jenny List has written a comprehensive guide to Widlar's μA723 in context of this project. Please follow her guide for the interesting things that this chip and board can achieve.
Additional information
Community contributions for this project
Open source circuit board design files