This paper reports a 500-gate array implemented with AlGaAs/GaAs HBT’s, using an ECL/CML circuit approach. The HBT’s have f1’s and fmax’s above 55 GHz. Frequency dividers personalized on this gate array have shown flip-flop toggle rates up to 15.6 GHz, the highest ever demonstrated with gate arrays. Measurement on delay chains at 2-mA source current showed unloaded gate delay of 26 ps, and additional delays of 8 ps/fan-out and 0.12 ps/fF of capacitive load. The gate array has been fabricated successfully in a research laboratory and in a pilot production facility.