The SY10/100E154 offer five 2:1 multiplexers followed by latches with differential outputs, designed for use in new, high-performance ECL systems. The two external Latch-Enable signals (LEN1, LEN2) are gated through a logical OR operation before use as control for the five latches. When both LEN1 and LEN2 are at a logic LOW, the latches are transparent, thus presenting the data from the multiplexers at the output pins. If either LEN1 or LEN2 (or both) are at a logic HIGH, the outputs are latched. The multiplexer operation is controlled by the SEL(Select) signal which selects one of the two bits of input data at each mux to be passed through.