HD74HC490 Overview
This circuit contains eight master-slave flip-flops and additional gating to implement two individual 4-bit decade counters. Each decade counter has individual clock, clear and set-to-9 inputs. BCD count sequences of any length up to divide-by-100 may be implemented with a single HD74HC490.
HD74HC490 Key Features
- High Speed Operation: tpd (Clock to QA) = 13 ns typ (CL = 50 pF) High Output Current: Fanout of 10 LSTTL Loads Wide Oper
- 0.5 1.35 1.8
- 0.5 1.5 3.15 4.2
- 1.9 4.4 5.9 4.13 5.63
- Output voltage
- 4.4 4.5
- 5.9 6.0
- Input current Quiescent supply current
- 95 19 16 10 pF ns ns ns ns Set-to-9 to Q B, QC ns Set-to-9 to Q A, QD ns Clear to any output ns Clock to QC ns Clock to
- 80 16 14