T74LS90, T74LS92/93 Counters: LS90 Decade LS92 Divide By Twelve LS93 4-Bit Binary
The T74LS90 T74LS92 and T74LS93 are high speed 4-bit ripple type counters partitioned into two sections. Each counter has a divide-by-two section and either a divide-by-five (LS90), or divide-by-eight (LS93) section which are triggered by a HIGH-to-LOW transition on the clock inputs. Each section can be used separately or tied together (Q to CP) to from BCD, bi-quinary, modulo-12, or modulo-16 counters. All of the counters have a 2-input gated Master Reset (Clear), and LS90 also has a 2-Input gated Master Set(Preset 9).