Switched guard modules target low-leakage current measurement in semiconductor parametric testing

Pickering Interfaces has announced a family of low leakage switching solutions targeting low current driven-guard measurements in semiconductor parametric test applications such as WAT (wafer acceptance testing). The cross-platform products include PXI, PXIe, and LXI versions and are based on the switched guard design principle, with the overall designs ensuring isolation resistances of up to 1013-Ohm.

The product family consists of three ranges delivering various switching topologies. The PXI module, model 40-121, provides SPST (13 or 26) or 2:1 (8 or 16) multiplexer configurations. The PXI/PXIe modules, model 40-590 and model 42-590, deliver matrix (8x4 or 16x4) functionality, while the LXI, model 65-290, is based on the company's established 2U LXI modular chassis (model 65-200) and accepts up to six 8x16 or 16x16 matrix plugins. Individual plugins are loaded into the front of the chassis, which is advantageous for expansion and maintenance.

To allow future test system scalability, PXI/PXIe models 40/42-590 and LXI model 65-290 products include loop-thru functionality, whereby the matrix size may be extended by interconnecting adjacent modules in a chassis via short standard cables – the former permits expansion on the X-axis, and the latter enables X and Y-axis expansion, enabling flexible matrix sizes up to 16x96 per chassis with simple expansion into additional chassis. Each PXI module occupies just one chassis slot. This footprint is achieved using high-density coaxial connectors to support low–leakage–driven–guard measurements. The PXI model 40-121 modules utilise multiway MS-M connectors with all fifty-two pins (SPST configuration) distributed between just two connectors, significantly speeding up connect and disconnect operations. Models 40/42-590 and 65-290 families employ MMCX micro-miniature coaxial connectors with insulated covers, providing compact single ports that reduce wiring complexity and facilitate the simple loop-thru expansion of the matrix size.

The LXI model 65-200 platform also allows users to load pre-defined test sequences and increment them via software or hardware triggers, reducing test times compared to standard software driver control transactions. The sequences are stored on the LXI controller, reducing the burden on the Host CPU and Ethernet traffic and minimising overall system latency. These features will optimise usage in semiconductor testing, where many thousands of tests may be needed per DUT.

Steve Edwards, switching product manager at Pickering, comments: "All products employ custom-designed, high-quality ruthenium sputtered reed relays manufactured by our relay division, Pickering Electronics. These switches feature an internal construction that maintains the necessary isolation for the new switched guard modules and ensures a long service life. Pickering also offers standard and custom cable solutions that can aid with integrating the products into users' test systems."

The company's standard three-year warranty covers all modules.