It was the beginning of July, on an English summer’s day—overcast and raining—as I drove up to Cheshire the pretty way, across the Derbyshire dales, to avoid the traffic problems on the M6 motorway. It was well worth the journey when I arrived at the premises of RoBAT Ltd., in Macclesfield, to meet with Managing Director Bruce Nockton.
RoBAT has a long-established name in high-speed signal integrity testing of complex assemblies and more recently, has offered a fully automatic impedance tester for bare boards. I was curious to learn more, and Nockton was happy to enlighten me.
I confessed at the start that I was basically a chemist who knew a bit about making PCBs but not a lot about the electronics of signal transmission, although I was aware of the increasingly critical importance of establishing the right combination of material properties and the precision of fabrication to achieve a product with specific electrical characteristics. Nockton kindly stayed with the basics and avoided getting too theoretical with his account of the development of RoBAT’s extensive product portfolio.
Describing the origins of the company, he explained that his early experience was with the design and manufacture of specialist test fixtures, particularly for large backplane assemblies. But by the late ’90s, frequent design revisions resulting from the rapid evolution of mobile phone infrastructure were making it uneconomical to produce dedicated fixtures for this type of assembly, creating an opportunity for an alternative approach. Flying probe testing had its mechanical limitations when using its typically long probes to consistently and reliably contact features like vertical pins and certain female connectors.
In 2003, Nockton and his colleagues devised a solution which he described as a cross between a test fixture and a flying probe, with an X-Y-Z-axis gantry system picking up individual “tools” from a magazine, which were effectively “mini test fixtures.” He showed me a selection of these tools, uniform in overall shape but each having probes on one face matching a specific connector on the backplane, while on the opposite side was a common interface to the testing machine.
To read this entire article, which appeared in the July 2024 issue of PCB007 Magazine, click here.