The SN54/74LS168 and SN54/74LS169 are fully synchronous 4-stage up/down counters featuring a preset capability for programmable operation, carry lookahead for easy cascading and a U/D input to control the direction of counting. The SN54/74LS168 counts in a BCD decade (8, 4, 2, 1) sequence, while the SN54/74LS169 operates in a Modulo 16 binary sequence. All state changes, whether in counting or parallel loading, are initiated by the LOW-to-HIGH transition of the clock.

• Low Power Dissipation 100 mW Typical
• High-Speed Count Frequency 30 MHz Typical
• Fully Synchronous Operation
• Full Carry Lookahead for Easy Cascading
• Single Up/Down Control Input
• Positive Edge-Trigger Operation
• Input Clamp Diodes Limit High-Speed Termination Effects