A HIGH-PERFORMANCE GAAS PIN ELECTRONICS CIRCUIT FOR AUTOMATIC TEST EQUIPMENT

A GaAs MESFET pin electronics circuit suitable for automated test equipment (ATE) has been designed and tested. A driver, window comparator, and programmable load has been integrated on a single chip. The driver has a variable amplitude of 0 to 7 V, a variable rise/fall time of 250 ps to 5 ns, and a 50-OMEGA output impedance. The driver has a real-time high-impedance inhibit mode that disconnects and reconnects ''on the fly'' at rates equal to the data rate (>1 Gb/s). Additionally, the voltage compliance of the driver in inhibit mode exceeds the high and low output levels by any amount within the -4-V to 7-V compliance window. Pattern dependent delay is typically +/-50 ps. The two comparators operate over the same compliance window with a dispersion in propagation delay of less than 100 ps for an overdrive of greater than 100 mV. The comparators have a high input impedance, low bias current, and show no evidence of oscillation when being overdriven by slow dV/dt input signals. The programmable load provides a sinking capability of greater than 50 mA over the compliance range,