SN54LVC138A, SN74LVC138A

3-LINE TO 8-LINE DECODERS/DEMULTIPLEXERS

SCAS291I – MARCH 1993 – REVISED OCTOBER 1998

6

POST OFFICE BOX 655303

PARAMETER

TEST

VCC = 1.8 V VCC = 2.5 V VCC = 3.3 V

UNIT

PARAMETER

CONDITIONS

TYP

TYP

TYP

UNIT

Cpd

Power dissipation capacitance

f = 10 MHz

25

26

27

pF

PARAMETER MEASUREMENT INFORMATION

VCC/2

VCC/2

VCC/2

VCC/2

VCC/2

VCC/2

VCC/2

VCC/2

VOH

VOL

th

tsu

From Output

Under Test

CL = 30 pF

(see Note A)

LOAD CIRCUIT

S1

Open

GND

1 k

Ω

1 k

Ω

Output

Control

(low-level

enabling)

Output

Waveform 1

S1 at 2

× VCC

(see Note B)

Output

Waveform 2

S1 at Open

(see Note B)

tPZL

tPZH

tPLZ

tPHZ

0 V

VOL + 0.15 V

VOH – 0.15 V

0 V

VCC

0 V

0 V

tw

VCC

VCC

VOLTAGE WAVEFORMS

SETUP AND HOLD TIMES

VOLTAGE WAVEFORMS

PULSE DURATION

VOLTAGE WAVEFORMS

ENABLE AND DISABLE TIMES

Timing

Input

Data

Input

Input

tpd

tPLZ/tPZL

tPHZ/tPZH

Open

2

× VCC

Open

TEST

S1

NOTES: A. CL includes probe and jig capacitance.

B. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control.

Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control.

C. All input pulses are supplied by generators having the following characteristics: PRR

≤ 10 MHz, ZO = 50 Ω, tr ≤ 2 ns, tf ≤ 2 ns.

D. The outputs are measured one at a time with one transition per measurement.

E. tPLZ and tPHZ are the same as tdis.

F. tPZL and tPZH are the same as ten.

G. tPLH and tPHL are the same as tpd.

0 V

VCC

VCC/2

tPHL

VCC/2

VCC/2

VCC

0 V

VOH

VOL

Input

Output

VOLTAGE WAVEFORMS

PROPAGATION DELAY TIMES

VCC/2

VCC/2

tPLH

2

× VCC

VCC

Figure 1. Load Circuit and Voltage Waveforms