Instek GDS-820C Teardown

Zoom of a portion of the input circuitry

Teardown of the Instek GDS-820C oscilloscope on a lazy Friday afternoon.

It’s a fairly interesting design, two layer boards, no parts are leadless. The finest pitch components are the Altera FPGA and the Freescale CPU. Definitely “older” technology than a modern Tek or Agilent scope. Looks like a prototype I might build. It’s a good design to look at for inspiration.

Some highlights

• The scope claims a 150MHz analog bandwith with “ET25GS/s”, it has a pair of 100MS/s Analog Devices AD9283 analog to digital converters
• There is a trigger daughter card that has a delay line made of coiled coax
• Many of the high speed analog cards – the input boards, trigger stuff – are labeled “SparkGap” rather than Instek
• There is a configuration dip switch on the board which controls the display and UI with silkscreen marks indicating which options the scope has

In the future, I may reverse engineer the input signal chain.