A new 4x4 array of active bipolar transistor crosspoints

Discusses a new 4/spl times/4 array of active bipolar transistor crosspoints realized for use in private branch telephone exchanges (PBX). It achieves low insertion loss by internal feedback and solves the interconnection problem cell by cell without a double metal layer or cross-chip bonding. Each crosspoint cell also includes a flip-flop for pulse triggering. The total number of pins is reduced to 25. The 4/spl times/4 crosspoint chip measures 3.0/spl times/2.9 mm and can easily be implemented in any higher order matrix.