Datasheet
SCLS171E − MARCH 1984 − REVISED SEPTEMBER 2003
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
recommended operating conditions (see Note 3)
SN54HCT138 SN74HCT138
UNIT
MIN NOM MAX MIN NOM MAX
UNIT
V
CC
Supply voltage 4.5 5 5.5 4.5 5 5.5 V
V
IH
High-level input voltage V
CC
= 4.5 V to 5.5 V 2 2 V
V
IL
Low-level input voltage V
CC
= 4.5 V to 5.5 V 0.8 0.8 V
V
I
Input voltage 0 V
CC
0 V
CC
V
V
O
Output voltage 0 V
CC
0 V
CC
V
∆t/∆v Input transition rise/fall time 500 500 ns
T
A
Operating free-air temperature −55 125 −40 85 °C
NOTE 3: All unused inputs of the device must be held at V
CC
or GND to ensure proper device operation. Refer to the TI application report,
Implications of Slow or Floating CMOS Inputs, literature number SCBA004.
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
V
CC
T
A
= 25°C SN54HCT138 SN74HCT138
UNIT
PARAMETER
TEST CONDITIONS
V
CC
MIN TYP MAX MIN MAX MIN MAX
UNIT
V
OH
V
I
= V
IH
or V
IL
I
OH
= −20 µA
4.5 V
4.4 4.499 4.4 4.4
V
V
OH
V
I
= V
IH
or V
IL
I
OH
= −4 mA
4.5 V
3.98 4.3 3.7 3.84
V
V
OL
V
I
= V
IH
or V
IL
I
OL
= 20 µA
4.5 V
0.001 0.1 0.1 0.1
V
V
OL
V
I
= V
IH
or V
IL
I
OL
= 4 mA
4.5 V
0.17 0.26 0.4 0.33
V
I
I
V
I
= V
CC
or 0 5.5 V ±0.1 ±100 ±1000 ±1000 nA
I
CC
V
I
= V
CC
or 0, I
O
= 0 5.5 V 8 160 80 µA
∆I
CC
†
One input at 0.5 V or 2.4 V,
Other inputs at 0 or V
CC
5.5 V 1.4 2.4 3 2.9 mA
C
i
4.5 V
to 5.5 V
3 10 10 10 pF
†
This is the increase in supply current for each input that is at one of the specified TTL voltage levels, rather than 0 V or V
CC
.
switching characteristics over recommended operating free-air temperature range, C
L
= 50 pF
(unless otherwise noted) (see Figure 1)
PARAMETER
FROM
TO
V
CC
T
A
= 25°C SN54HCT138 SN74HCT138
UNIT
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
V
CC
MIN TYP MAX MIN MAX MIN MAX
UNIT
A, B, or C
Any Y
4.5 V 23 36 54 45
t
pd
A, B, or C Any Y
5.5 V 17 32 49 34
ns
t
pd
Enable
Any Y
4.5 V 22 33 50 42
ns
Enable Any Y
5.5 V 18 30 45 38
t
t
Y
4.5 V 12 15 22 19
ns
t
t
Y
5.5 V 11 14 20 17
ns
operating characteristics, T
A
= 25°C
PARAMETER TEST CONDITIONS TYP UNIT
C
pd
Power dissipation capacitance No load 85 pF