An application of photoconductive switch for high-speed testing

This paper describes a high speed test technique for CMOS device with I/O terminals using photoconductive switch (PC-switch). Since the switching speed of the PC-switch is high, it can be utilized by fast test systems. The PC-switch uses indium phosphide (InP), and has an on-resistance 40-60 /spl Omega/, a switching time of 1 ns, a capacitance between terminals of 31 fF, and a break down voltage 9.5 V. The PC-switch can be used with a laser diode (LD) to implement an optical driven line switch (ODLS). The performance of ODLS is suitable for testing devices with high speed I/O pins. The ROUND TRIP DELAY of less than 500 ps is achievable by assembling the I/O switch on a performance board in close proximity to the device pin. The I/O switching characteristics of this PC-switch have been verified by simulation and experimentation.