OSH Park
Unobtainium-400
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Unobtainium-400
by
mrnuke.
2
layer board of
1.50x0.75
inches
(38.13x19.08
mm).
Shared on
June 26th, 2016 07:16.
Tektronix Unobtainium 400 hybrid replacement (U400)
Ever had a Tektronix U400 channel switch IC go bad on you? Unobtainium hard to get? Don’t care about high frequency performance and channel A+B feature? Then Unobtainium-400 has you covered. For under ten dollars, you can be the proud owner of not one, not two, but three U400 low-performance equivalent hybrids.
This is a prototype to see how feasible it is to develop a full-featured replacement for the infamously fail-prone Tektronix channel switch from the 2400 series of analog oscilloscopes. Also known as U400, since it receives that designation on virtually all scopes in the series.
The current prototype doesn’t support the A+B channel addition feature, and bandwidth is limited by the switch IC. 40MHz is to be expected on standard CD4051 ICs, though some TI 74HC4051 muxes can go as high as 200MHz. Proper routing of the differential pairs is made difficult by the use of separate ICs for switching the + and - lines. This further limits performance of the prototype.