74系列逻辑芯片/74HC163D
GENERAL DESCRIPTION
The 74HC/HCT163 are high-speed Si-gate CMOS devices and are pin compatible with low power Schottky TTL LSTTL. They are specified in compliance with JEDEC standard no. 7A. The 74HC/HCT163 are synchronous presettable binary counters which feature an internal look-ahead carry and can be used for high-speed counting. Synchronous operation is provided by having all flip-flops clocked simultaneously on the positive-going edge of the clock CP. The outputs Q0 to Q3 of the counters may be preset to a HIGH or LOW level. A LOW level at the parallel enable
input PE disables the counting action and causes the data at the data inputs D0to D3 to be loaded into the counter on the positive-going edge of the clock providing that the set-up and hold time requirements for PE are met.
FEATURES
• Synchronous counting and loading
• Two count enable inputs for n-bit cascading
• Positive-edge triggered clock
• Synchronous reset
• Output capability: standard
• ICCcategory: MSI