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Is Now Part of
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of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent-Marking.pdf. ON Semiconductor reserves the right
to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. Buyer is responsible for its products and applications using ON
Semiconductor products, including compliance with all laws, regulations and safety requirements or standards, regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON
Semiconductor data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s
technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not designed, intended, or authorized for use as a critical component in life support systems or any FDA
Class 3 medical devices or medical devices with a same or similar classification in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended
or unauthorized application, Buyer shall indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, afliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out
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is an Equal Opportunity/Afrmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.
© 2003 Fairchild Semiconductor Corporation DS009925 www.fairchildsemi.com
November 1988
Revised July 2003
74AC138 • 74ACT138 1-of-8 Decoder/Demult iplexer
74AC138 74ACT138
1-of-8 Decoder/Demultiplexer
General Description
The AC/ACT138 is a high-speed 1-of-8 decoder/demulti-
plexer. This device is ideally suited for high-speed bipolar
memory chip select address decoding. The multiple input
enables allow parallel expansion to a 1-of-24 decoder
using just three AC/ACT138 devices or a 1-o f-32 decoder
using four AC/ACT138 devices and one inverter.
Features
ICC reduced by 50%
Demultiplexing capability
Multiple input enable for easy expansion
Active LOW mutually exclusive outputs
Outputs source/sink 24 mA
ACT138 has TTL-compatible inputs
Ordering Code:
Device a ls o av ailable in Tape and Ree l. Specify by app ending suffix let te r “X” to the ordering code .
Connection Diagram
Pin Descriptions
Logic Symbols
IEEE/IEC
FACT is a trademark of Fairchild Semiconductor Corporation.
Order Number Package Number Package Description
74AC138SC M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow
74AC138SJ M16D 16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
74AC138MTC MTC16 16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
74AC138PC N16E 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide
74ACT138SC M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow
74ACT138SJ M16D 16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
74ACT138PC N16E 16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide
Pin Names Description
A0A2Address Inputs
E1E2Enable Inputs
E3Enable Input
O0O7Outputs
www.fairchildsemi.com 2
74AC138 74ACT138
Truth Table
H = HIGH Voltage Le ve l L = LOW Voltage Level X = Immaterial
Functional Description
The AC/ACT138 high-speed 1-of-8 decoder/demultiplexer
accepts three binary weighted inputs (A0, A1, A2) and,
when enabled, provides eight mutually exclusive active-
LOW outputs (O0O7). The AC/ACT138 features three
Enable inputs, two active-LOW (E1, E2) and one active-
HIGH (E3). All outputs will be HIGH unless E1 and E2 are
LOW and E3 is HIGH. This multiple ena ble function a llows
easy para lle l expansion of the de vice to a 1-of-32 (5 lines
to 32 li ne s) d eco der with j u st fo ur AC /ACT1 38 d evice s an d
one i nverter (see Figure 1). The AC/ACT13 8 can be use d
as an 8-output demultiplexer by using one of the active
LOW En abl e inp uts as the data i n pu t an d the oth er E nab le
inputs as strobes. The Enable inputs which are not used
must be pe rmanently tied to their appro priate active-H IGH
or active-LOW state.
Logic Diagram
Please note that this diagram is provided only for the understanding of logic
operations and should not be used to estimate propagation delays.
FIGURE 1. Expansion to 1-of-32 De coding
Inputs Outputs
E1E2E3A0A1A2O0O1O2O3O4O5O6O7
HXXXXXHHHHHHHH
XHXXXXHHHHHHHH
XXLXXXHHHHHHHH
LLHLLLLHHHHHHH
LLHHLLHLHHHHHH
LLHLHLHHLHHHHH
LLHHHLHHHLHHHH
LLHLLHHHHHLHHH
LLHHLHHHHHHLHH
LLHLHHHHHHHHLH
LLHHHHHHHHHHHL
3 www.fairchildsemi.com
74AC138 74ACT138
Absolute Maxim um Ratings(Note 1) Recommended Operating
Conditions
Note 1: Absol ut e maximum ratings are thos e v alues beyond whi c h damage
to the dev ice may occ ur. The databoo k specific ations sh ould be m et, with-
out exc eption, to e nsure that the system des ign is reliable over its power
supply, temperature, and output/input loading variables. Fairchild does not
recommend operation of FACT circuit s outside dat abook specif ic at ions.
DC Electrical Characteristics for AC
Note 2: All outputs lo aded; thres holds on inpu t as s oc iated with ou t put under test .
Note 3: Maximum test duration 2.0 ms, one output loaded at a time.
Note 4: IIN and ICC @ 3.0V are gu aranteed to b e les s t han or equal t o th e respective limit @ 5.5V VCC.
Supply Voltage (VCC)0.5 V to +7.0V
DC Input Diode Current (IIK)
VI = 0.5V 20 mA
VI = VCC + 0.5V +20 mA
DC Input Voltage (VI)0.5V to VCC + 0.5V
DC Output Diode Current (IOK)
VO = 0.5V 20 mA
VO = VCC + 0.5V +20 mA
DC Output Voltage (VO)0.5V to VCC + 0.5V
DC Output Source
or Sink Current (IO)±50 mA
DC VCC or Ground Current
per Output Pin (ICC or IGND)±50 mA
Storage Temperature (TSTG)65°C to +150°C
Junction Temperature (TJ)
PDIP 140°C
Supply Voltage (VCC)
AC 2.0V to 6.0V
ACT 4.5V to 5.5V
Input Voltage (VI)0V to V
CC
Output Voltage (VO)0V to V
CC
Operating Temperature (TA)40°C to +85°C
Minimum Input Edge Rate (V/t)
AC Devices
VIN from 30% to 70% of VCC
VCC @ 3.3V, 4.5V, 5.5V 125 mV/ns
Minimum Input Edge Rate (V/t)
ACT Devices
VIN from 0.8V to 2.0V
VCC @ 4.5V, 5.5V 125 mV/ns
Symbol Parameter VCC TA = +25°CT
A = 40°C to +85°CUnits Conditions
(V) Typ Guaranteed Limits
VIH Minimum HIGH Level 3.0 1.5 2.1 2.1 VOUT = 0.1V
Input Voltage 4.5 2.25 3.15 3.15 V or VCC 0.1V
5.5 2.75 3.85 3.85
VIL Maximum LOW Level 3.0 1.5 0.9 0.9 VOUT = 0.1V
Input Voltage 4.5 2.25 1.35 1.35 V or VCC 0.1V
5.5 2.75 1.65 1.65
VOH Minimum HIGH Level 3.0 2.99 2.9 2.9
Output Voltage 4.5 4.49 4.4 4.4 V IOUT = 50 µA
5.5 5.49 5.4 5.4 VIN = VIL or VIH
3.0 2.56 2.46 IOH = 12 mA
4.5 3.86 3.76 V IOH = 24 mA
5.5 4.86 4.76 IOH = 24 mA (Note 2)
VOL Maximum LOW Level 3.0 0.002 0.1 0.1
Output Voltage 4.5 0.001 0.1 0.1 V IOUT = 50 µA
5.5 0.001 0.1 0.1 VIN = VIL or VIH
3.0 0.36 0.44 IOL = 12 mA
4.5 0.36 0.44 V IOL = 24 mA 0
5.5 0.36 0.44 IOL = 24 mA (Note 2)
IIN Maximum Input 5.5 ±0.1 ±1.0 µAV
I = VCC, GND
(Note 4) Leakage Current
IOLD Minimum Dynamic 5.5 75 mA VOLD = 1.65V Max
IOHD Output Current (Note 3) 5.5 75 mA VOHD = 3.85V Min
ICC
(Note 4) Maximum Quiescent
Supply Curre nt 5.5 4.0 40.0 µAV
IN = VCC or GND
www.fairchildsemi.com 4
74AC138 74ACT138
DC Electrical Characteristics for ACT
Note 5: All outputs loaded; thresholds on input assoc iat ed with outp ut under test.
Note 6: Maximum test dura tio n 2. 0 ms, one ou t put loaded at a tim e.
AC Electrical Characteristics for AC
Note 7: Voltage Range 3.3 is 3.3V ± 0.3V
Voltage Range 5. 0 is 5. 0V ± 0.5V
Symbol Parameter VCC TA = +25°CT
A = 40°C to +85°CUnits Conditions
(V) Typ Guaranteed Limits
VIH Minimum HIGH Level 4.5 1.5 2.0 2.0 VVOUT = 0.1V
Input Voltage 5.5 1.5 2.0 2.0 or VCC 0.1V
VIL Maximum LOW Level 4.5 1.5 0.8 0.8 VVOUT = 0.1V
Input Voltage 5.5 1.5 0.8 0.8 or VCC 0.1V
VOH Minimum HIGH Level 4.5 4.49 4.4 4.4 VI
OUT = 50 µA
Output Voltage 5.5 5.49 5.4 5.4 VIN = VIL or VIH
4.5 3.86 3.76 V IOH = 24 mA
5.5 4.86 4.76 IOH = 24 mA (Note 5)
VOL Maximum LOW Level 4.5 0.001 0.1 0.1 VI
OUT = 50 µA
Output Vo ltage 5 .5 0.001 0.1 0.1 VIN = VIL or VIH
4.5 0.36 0.44 V IOL 24 mA
5.5 0.36 0.44 IOL.= 24 mA (Note 5)
IIN Maximum Input 5.5 ±0.1 ±1.0 µAV
I = VCC, GND
Leakage Current
ICCT Maximum 5.5 0.6 1.5 mA VI = VCC 2.1V
ICC/Input
IOLD Minimum Dynamic 5.5 75 mA VOLD = 1.65V Max
IOHD Output Current (Note 6) 5.5 75 mA VOHD = 3.85V Min
ICC Maximum Quiescent 5.5 4.0 40.0 µAV
IN = VCC or GND
Supply Current
VCC TA = +25°CT
A = 40°C to +85°C
Symbol Parameter (V) CL = 50 pF CL = 50 pF Units
(Note 7) Min Typ Max Min Max
tPLH Propagation Delay 3.3 1.5 8.5 13.0 1.5 15.0 ns
An to On5.0 1.5 6.5 9.5 1.5 10.5
tPHL Propagation Delay 3.3 1.5 8.0 12.5 1.5 14.0 ns
An to On5.0 1.5 6.0 9.0 1.5 10.5
tPLH Propagation Delay 3.3 1.5 11.0 15.0 1.5 16.0 ns
E1 or E2 to On5.0 1.5 8.0 11.0 1.5 12.0
tPHL Propagation Delay 3.3 1.5 9.5 13.5 1.5 15.0 ns
E1 or E2 to On5.0 1.5 7.0 9.5 1.5 10.5
tPLH Propagation Delay 3.3 1.5 11.0 15.5 1.5 16.5 ns
E3 to On5.0 1.5 8.0 11.0 1.5 12.5
tPHL Propagation Delay 3.3 1.5 8.5 13.0 1.5 14.0 ns
E3 to On5.01.56.08.01.09.5
5 www.fairchildsemi.com
74AC138 74ACT138
AC Electrical Characteristics for ACT
Note 8: Voltage Range 5. 0 is 5. 0V ± 0.5V
Capacitance
VCC TA = +25°CT
A = 40°C to +85°C
Symbol Parameter (V) CL = 50 pF CL = 50 pF Units
(Note 8) Min Typ Max Min Max
tPLH Propagation Delay 5.0 1.5 7.0 10.5 1.5 11.5 ns
An to On
tPHL Propagation Delay 5.0 1.5 6.5 10.5 1.5 11.5 ns
An to On
tPLH Propagation Delay 5.0 2.5 8.0 11.5 2.0 12.5 ns
E1 or E2 to On
tPHL Propagation Delay 5.0 2.0 7.5 11.5 2.0 12.5 ns
E1 or E2 to On
tPLH Propagation Delay 5.0 2.5 8.0 12.0 2.0 13.0 ns
E3 to On
tPHL Propagation Delay 5.0 2.0 6.5 10.5 1.5 11.5 ns
E3 to On
Symbol Parameter Typ Units Conditions
CIN Input Capacitance 4.5 pF VCC = OPEN
CPD Power Dissipation Capacitance 60.0 pF VCC = 5.0V
www.fairchildsemi.com 6
74AC138 74ACT138
Physical Dimensions inches (millimeters) unless otherwise noted
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow
Package Number M16A
7 www.fairchildsemi.com
74AC138 74ACT138
Physical Dim ensions inches (millimeters) unless otherwise noted (Continued)
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
Package Number M16D
www.fairchildsemi.com 8
74AC138 74ACT138
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
Package Number MTC16
9 www.fairchildsemi.com
74AC138 74ACT138 1-of-8 Decoder/Demultip lexer
Physical Dim ensions inches (millimeters) unless otherwise noted (Continued)
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide
Package Number N16E
Fairchild does not assume an y responsibility for use of any circuitry descr ib ed, no circuit patent licenses are implied and
Fairchild reserves the right at any time without notice to change said circuitry and specifications.
LIFE SUPPORT POLICY
FAIRCHILDS PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD
SEMICONDUCTOR CORPORATION. As used herein:
1. Life suppor t de vices o r syst ems are dev ic es or syste ms
which, (a) are intended for surgical implant into the
body, or (b) support or sustain life, and (c) whose failure
to perform when properly used in accordance with
instruct ions fo r use pr ovi de d in the l abe ling, can be rea-
sonably expected to result in a significant injury to the
user.
2. A crit ical componen t in any com ponen t of a life s uppor t
device or system whose failure to perform can be rea-
sonabl y e xpec ted to cause the fa i lure of the l ife support
device or system, or to affect its safety or effectiveness.
www.fairchildsemi.com
www.onsemi.com
1
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coverage may be accessed at www.onsemi.com/site/pdf/PatentMarking.pdf. ON Semiconductor reserves the right to make changes without further notice to any products herein.
ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
Buyer is responsible for its products and applications using ON Semiconductor products, including compliance with all laws, regulations and safety requirements or standards,
regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON Semiconductor data sheets and/or
specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer
application by customer’s technical experts. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not
designed, intended, or authorized for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classification
in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorized
application, Buyer shall indemnify and hold ON Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and
expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such
claim alleges that ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor is an Equal Opportunity/Affirmative Action Employer. This
literature is subject to all applicable copyright laws and is not for resale in any manner.
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