Pris 10 kr.
NXP HEF4518BP 4-Bit Tæller, BCD Optæller; Envejs.
The HEF4518B is a dual 4-bit internally synchronous BCD counter. The counter has an
active HIGH clock input (nCP0) and an active LOW clock input (nCP1), buffered outputs
from all four bit positions (nQ0 to nQ3) and an active HIGH overriding asynchronous
master reset input (nMR). The counter advances on either the LOW-to-HIGH transition of
the nCP0 input if nCP1 is HIGH or the HIGH-to-LOW transition of the nCP1 input if nCP0
is LOW. Either nCP0 or nCP1 may be used as the clock input to the counter and the other
clock input may be used as a clock enable input. A HIGH on nMR resets the counter (nQ0
to nQ3 = LOW) independent of nCP0, nCP1. Schmitt trigger action in the clock input
makes the circuit highly tolerant of slower clock rise and fall times.
It operates over a recommended VDD power supply range of 3 V to 15 V referenced to VSS
(usually ground). Unused inputs must be connected to VDD, VSS, or another input