A 12-ps-resolution digital variable-delay macro cell on GaAs 100 K-gates gate array using a meshed air bridge structure

A digital variable-delay macro cell (DVDM) on a GaAs 100 K-gates gate array has been developed for measurement instruments and for elimination of clock skew on printed circuit boards. Three new technologies for high resolution are introduced into the DVDM: (1) a meshed air bridge structure bringing 29% reduction of propagation delay, (2) a rising edge selector circuit creating 33% decrement of standard deviation /spl sigma/ on delay, and (3) a delay circuit with a discharge control path for a high resolution of 12 ps. The DVDM produces 24.4 ns span and 12 ps resolution, about one-quarter that of a conventional DVDM. Linearity error is less than /spl plusmn/27 ps. Power dissipation of the DVDM is 250 mW/cell, about one-third of the value for a conventional Si bipolar junction transistor analog delay circuit.