Description

74LS90 is basically a MOD-10 decade counter that generate a BCD output code. It consists of four master-slave JK flip-flop, which are internally connected to provide MOD-2 (count to 2) counter and MOD-5 counter. 74LS90 also have an independent toggle JK flip-flop by CLKA and other three are driven by the CLKB.
Typical power dissipation: 45mW
High count rates: 42MHz
Choice of counting modes
Input Clamp Diodes Limit High-Speed Termination Effect
Supply voltage: 5V
Operating Ambient Temperature Range: –55 to 125°C
Equivalents
74LS92, 74LS93