SN54LS490, SN74LS490

DUAL 4-BIT DECADE COUNTERS

SDLS125A – OCTOBER 1976 – REVISED JULY 1998

7

POST OFFICE BOX 655303

PARAMETER MEASUREMENT INFORMATION

SET9

1.3 V

1.3 V

1.3 V

1.3 V

CLR

CLK

QA

QD

QC

QB

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

1.3 V

tsu

tsu

tw(clock)

3 V

0 V

3 V

0 V

3 V

0 V

VOH

VOL

VOH

VOL

VOH

VOL

tPLH

(Measure at

tn + 1)

tPLH

tPHL

tPHL

(Measure at

tn + 2)

tPHL

tPHL

tPHL

tPLH

(Measure at

tn + 2)

tPHL

(Measure at

tn + 4)

tPHL

tPHL

tPHL

tPLH

(Measure at

tn + 4)

tPLH

(Measure at

tn + 8)

tPLH

tPHL

tPHL

tPHL

(Measure at

tn + 8)

tPHL

(Measure at

tn + 10)

NOTE A: Input pulses are supplied by a generator having the following characteristics: tr ≤ 15 ns, tf ≤ 6 ns, PRR ≤ 1 MHz, duty cycle = 50%,

ZO ≈ 50 Ω.

VOH

VOL

Figure 1. Voltage Waveforms