74AHCT138
3 TO 8 LINE DECODER DEMULTIPLEXER
Description
The 74AHCT138 is an advanced high speed CMOS device that is
designed to be pin compatable with 74LS low power Schottky types.
The device accepts a three bit binary weighted address on input pins
A0, A1 and A2 and when enabled will produce one active low output
with the remaining seven being high.
There are two active LOW enable inputs E1 and E2, and one active
HIGH enable input E3. The disabled device state results in all outputs
being high. The enable state occurs with E1 and E2 asserted low and
E3 asserted high.
The multiple enable lines allow for the parallel expansion of decoders
to create 4-to-16 line versions with no additional parts and 5-to-32
versions with the addition of a single inverter.
Pin Assignments
Features
Supply Voltage Range from 4.5V to 5.5V
Sinks or Sources 8mA at V
CC
= 4.5V
CMOS Low Power Consumption
Schmitt Trigger Action at All Inputs
Inputs Accept up to 6.0V
ESD Protection Tested per JESD 22
Exceeds 200-V Machine Model (A115-A)
Exceeds 2000-V Human Body Model (A114-A)
Exceeds 1000-V Charged Device Model (C101C)
Latch-Up Exceeds 250mA per JESD 78, Class II
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)
1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See http://www.diodes.com for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and Lead-free.
3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and
<1000ppm antimony compounds.
Applications
Memory chip select decoding
Demultiplexing
Single line peripheral control
Allow simple serial bit streams from a microcontroller to control as
many peripheral lines as needed
Notes:
Click here for ordering information, located at the end of datasheet
74AHCT138
Document number: DS35483 Rev. 2 - 2
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© Diodes Incorporated
74AHCT138
Absolute Maximum Ratings
(Note 4) (@T
A
= +25°C, unless otherwise specified.)
Symbol
ESD HBM
ESD CDM
ESD MM
V
CC
V
I
V
o
I
IK
I
OK
I
OK
I
O
I
CC
I
GND
T
J
T
STG
P
TOT
Notes:
Description
Human Body Model ESD Protection
Charged Device Model ESD Protection
Machine Model ESD Protection
Supply Voltage Range
Input Voltage Range
Voltage applied to output in high or low state
Input Clamp Current
Output Clamp Current
Output Clamp Current
V
I
< -0.5V
V
O
<-0.5V
V
O
> V
CC
+ 0.5V
Rating
2
1
200
-0.5 to +7.0
-0.5 to +7.0
-0.3 to V
CC
+0.5
-20
-20
25
+/- 25
75
-75
-40 to +150
-65 to +150
500
Unit
KV
KV
V
V
V
V
mA
mA
mA
mA
mA
mA
°C
°C
mW
Continuous output current
Continuous current through V
DD
or GND
Continuous current through V
DD
or GND
Operating Junction Temperature
Storage Temperature
Total Power Dissipation
4. Stresses beyond the absolute maximum may result in immediate failure or reduced reliability. These are stress values and device operation should be
within recommend values.
Recommended Operating Conditions
(Note 5) (@T
A
= +25°C, unless otherwise specified.)
Symbol
V
CC
V
I
V
O
t/V
T
A
Note:
Parameter
Supply Voltage
Input Voltage
Output Voltage
Input transition Rise or Fall Rate
Operating Free-Air Temperature
Active Mode
Conditions
Min
4.5
0
0
-40
Max
5.5
5.5
V
CC
20
+125
Unit
V
V
V
ns/V
°C
V
CC
= 4.5V to 5.5V
5. Unused inputs should be held at V
CC
or Ground.
Electrical Characteristics
(@T
A
= +25°C, unless otherwise specified.)
Symbol
V
IH
V
IL
V
OH
V
OL
I
I
I
CC
∆I
CC
C
i
Parameter
High-level Input
Voltage
Low-level input
voltage
High Level
Output Voltage
I
OH
= -50μA
I
OH
= -8mA
Test Conditions
V
CC
4.5V to 5.5V
4.5V to 5.5V
4.5V
4.5V
4.5V
4.5V
0V to 5.5V
5.5V
4.5V to 5.5V
5.5V
T
A
= +25°C
Min
Typ Max
2.0
4.4
3.94
4.5
0
0.1
4
0.8
0.1
0.36
±0.1
4.0
1.35
10
T
A
= -40°C to +85°C T
A
= -40°C to +125°C
Min
Max
Min
Max
2.0
4.4
3.80
0.8
0.1
0.44
±1
40
1.5
10
2.0
4.4
3.70
0.8
0.1
0.55
±2
80
1.5
10
Unit
V
V
V
V
μA
μA
mA
pF
Low-level Output I
OL
= 50μA
Voltage
I
OL
= 8mA
Input Current
Supply Current
Additional
Supply Current
per Input
Input
Capacitance
V
I
= GND or 5.5V
V
I
= GND or V
CC
I
O
= 0
V
I
= Vcc -2.1V
I
O
= 0
V
i
= V
CC
or GND
74AHCT138
Document number: DS35483 Rev. 2 - 2
4 of 9
www.diodes.com
June 2013
© Diodes Incorporated
74AHCT138
Switching Characteristics
Symbol
Parameter
Test Conditions
V
CC
4.5V to 5.5V
4.5V to 5.5V
4.5V to 5.5V
4.5V to 5.5V
4.5V to 5.5V
4.5V to 5.5V
T
A
= +25°C
Min
Typ
Max
0.5
0.5
0.5
0.5
0.5
0.5
4.4
6.2
4.3
6.2
4.3
6.2
10.4
11.4
9.1
10.1
9.6
10.6
-40°C to +85°C
Min
1.0
1.0
1.0
1.0
1.0
1.0
Max
12.0
13.0
10.5
11.5
11.0
12.0
-40°C to +125°C
Min
1.0
1.0
1.0
1.0
1.0
1.0
Max
13.0
14.5
11.5
13.0
12.0
13.5
Unit
ns
ns
ns
Propagation Delay Figure 2 C
L
=15pF
An to Yn
Figure 2 C
L
= 50pF
t
PD
Propagation Delay Figure 2 C
L
= 15pF
E3 to Yn
Figure 2 C
L
= 50pF
Propagation Delay Figure 2 C
L
= 15pF
En to Yn
Figure 2 C
L
= 50pF
Operating Characteristics
(@T
A
= +25°C, unless otherwise specified.)
Parameter
C
pd
Power dissipation
capacitance
Test
Conditions
f = 1 MHz all outputs switching-no load
V
CC
= 5V
Typ
23
Unit
pF
Parameter Measurement Information
V
CC
4.5V to 5.5V
Inputs
V
I
3.0 V
t
r
/t
f
3ns
Input
1.5 V
V
M
Output
V
CC
/2
C
L
15pF, 50pF
Voltage Waveform
Pulse Duration
Voltage Waveform
Propagation Delay Times
Inverting and Non Inverting Outputs
Notes:
A. Includes test lead and test apparatus capacitance.
B. All pulses are supplied at pulse repetition rate
≤
10 MHz.
C. Inputs are measured separately one transition per measurement.
D. t
PLH
and t
PHL
are the same as t
PD
.
5 of 9
www.diodes.com
June 2013
© Diodes Incorporated
74AHCT138
Document number: DS35483 Rev. 2 - 2
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