高速CMOS逻辑可预置计数器 High-Speed CMOS Logic Presettable Counters
Description
The ’HC161, ’HCT161, ’HC163, and ’HCT163 are presettable synchronous counters that feature look-ahead carry logic for use in high-speed counting applications. The ’HC161 and ’HCT161 are asynchronous reset decade and binary counters, respectively; the ’HC163 and ’HCT163 devices are decade and binary counters, respectively, that are reset synchronously with the clock. Counting and parallel presetting are both accomplished synchronously with the negative-to-positive transition of the clock.
Features
• ’HC161, ’HCT161 4-Bit Binary Counter, Asynchronous Reset
• ’HC163, ’HCT163 4-Bit Binary Counter, Synchronous Reset
• Synchronous Counting and Loading
• Two Count Enable Inputs for n-Bit Cascading
• Look-Ahead Carry for High-Speed Counting
• Fanout Over Temperature Range
- Standard Outputs . . . . . . . . . . . . . . . 10 LSTTL Loads
- Bus Driver Outputs . . . . . . . . . . . . . 15 LSTTL Loads
• Wide Operating Temperature Range . . . -55oC to 125oC
• Balanced Propagation Delay and Transition Times
• Significant Power Reduction Compared to LSTTL Logic ICs
• HC Types
- 2V to 6V Operation
- High Noise Immunity: NIL = 30%, NIH = 30% of VCC at VCC = 5V
• HCT Types
- 4.5V to 5.5V Operation
- Direct LSTTL Input Logic Compatibility, VIL= 0.8V Max, VIH = 2V Min
- CMOS Input Compatibility, Il ≤ 1µA at VOL, VOH