© 2004 Fairchild Semiconductor Corporation DS012417 www.fairchildsemi.com
March 1995
Revised February 2004
74LCX138 Low Voltage 1-of-8 Decoder/Demultiplexer with 5V Tolerant Inputs
74LCX138
Low Voltage 1-of-8 Decoder/Demultiplexer
with 5V Tolerant Inputs
General Description
The LCX13 8 is a high- spee d 1-of-8 decoder /demu ltiplex er.
This device is ideally suited for high-speed memory chip
select ad dress decoding . The multip le input enabl es allow
parallel expansion to a 1-of-24 decoder using just three
LCX138 devices or a 1-of-32 decoder using four LCX138
devices and one inverter.
The 74LCX138 is fabricated with advanced CMOS technol-
ogy to achieve high speed operation while maintaining
CMOS low power dissipation.
Features
5V tolerant inputs
2.3V to 3.6V VCC specifications provided
6.0 ns tPD max (VCC = 3.3V), 10 µA ICC max
Power down high impedance inputs and outputs
±24 mA output drive (VCC = 3.0V)
Implements patented noise/EMI reduction circuitry
Latch-up per for man c e exce eds 500 mA
ESD performance :
Human body model > 2000V
Machine model > 200V
Leadless DQFN package
Ordering Code:
Note 1: Devices al so av ailable in Tape and Reel. Specif y by append ing suffix lette r “X” to the ordering co de.
Note 2: DQFN package available in Tape and Reel only.
Order Number Package
Number Package Desc ription
74LCX138M
(Note 1) M16A 16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow
74LCX138SJ
(Note 1) M16D 16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
74LCX138BQX
(Note 2) MLP016E 16-Terminal Depopulated Quad Very-Thin Flat Pack No Leads (DQFN), JEDEC MO-241,
2.5 x 3.5mm
74LCX138MTC
(Note 1) MTC16 16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
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74LCX138
Connection Diagrams
Pin Assignments for SOIC, SOP, and TSSOP
Pad Assignments for DQFN
(Top Through View)
Pin Descriptions
Functional Description
The LCX138 high-speed 1-of-8 decoder/demultiplexer
accepts three binary weighted inputs (A0, A1, A2) and,
when enabled, provides eight mutually exclusive active-
LOW ou tputs (O 0O7). T he LCX 138 feature s thre e Ena ble
inputs, two active -L OW (E 1, E2) an d one acti ve-HI GH (E 3).
All outputs will be HIGH unless E1 and E2 are LOW and E3
is HIGH . Th e LC X1 38 can b e u sed as an 8- outp ut d em ul ti-
plexer by using one of the active LOW Enable inputs as the
data input and the other Enable inputs as strobes. The
Enable inputs which are not used must be permanently tied
to their appropriate active-HIGH or active-LOW state.
Truth Table
H = HIGH Voltage Le ve l
L = LOW Voltage Level
X = Immaterial
Pin Nam es Descri ption
A0A2Address Inputs
E1E2Enable Inputs
E3Enable Input
O0O7Outputs
Inputs Outputs
E1E2E3A0A1A2O0O1O2O3O4O5O6O7
HXXXXXHHHHHHHH
XHXXXXHHHHHHHH
XXLXXXHHHHHHHH
LLHLLLLHHHHHHH
LLHHLLHLHHHHHH
LLHLHLHHLHHHHH
LLHHHLHHHLHHHH
LLHLLHHHHHLHHH
LLHHLHHHHHHLHH
LLHLHHHHHHHHLH
LLHHHHHHHHHHHL
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74LCX138
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.
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74LCX138
Absolute Maximum Ratings(Note 3)
Recommended Operating Conditions (Note 5)
Note 3: The Absolute Maximum Ratings are those values beyond which the safety of the device cannot be guaranteed. The device should not be operated
at these limits. The parametric values defined in the Electrical Characteristics tables are not guaranteed at the Absolute Maximum Ratings. The Recom-
mend ed Operating Co nditions ta ble will defi ne t he cond it ions for act ual device operation.
Note 4: IO Absolute Maximum Rating must be observed.
Note 5: Unused inputs must be held HIGH or LOW. They may not float.
DC Electrical Characteristics
Symbol Parameter Value Conditions Units
VCC Supply Voltage 0.5 to +7.0 V
VIDC Input Voltage 0.5 to +7.0 V
VODC Output Voltage 0.5 to VCC + 0.5 Output i n HIGH or LOW State (Note 4) V
IIK DC Input Diode Current 50 VI < GND mA
IOK DC Output Diode Current 50 VO < GND mA
+50 VO > VCC
IODC Output Source/Sink Current ±50 mA
ICC DC Supply Current per Supply Pin ±100 mA
IGND DC Ground C urrent per Ground Pin ±100 mA
TSTG Storage Temperature 65 to +150 °C
Symbol Parameter Min Max Units
VCC Supply Voltage Operating 2.0 3.6 V
Data Retention 1.5 3.6
VIInput Voltage 0.0 5.5 V
VOOutput Voltage HIGH or LOW State 0.0 VCC V
IOH/IOL Output Current VCC = 3.0V to 3.6V ±24.0 mAVCC = 2.7V to 3.0V ±12.0
VCC = 2.3V to 2.7V ±8.0
TAFree-Air Operating Temperature 40.0 85.0 °C
t/V Input Edge Rate, VIN = 0.8V to 2.0V, VCC = 3.0V 0.0 10.0 ns/V
Symbol Parameter Conditions VCC TA = 40°C to +85°CUnits
(V) Min Max
VIH HIGH Level Input Voltage 2.3 to 2.7 1.7 V
2.7 to 3.6 2.0
VIL LOW Level Input Voltage 2.3 to 2.7 0.7 V
2.7 to 3.6 0.8
VOH HIGH Level Output Voltage IOH = 100 µA 2.3 to 3.6 VCC 0.2
V
IOH = -8 mA 2.3 1.8
IOH = 12 mA 2.7 2.2
IOH = 18 mA 3.0 2.4
IOH = 24 mA 3.0 2.2
VOL LOW Level Output Voltage IOL = 100 µA 2.3 to 3.6 0.2
V
IOL = 8mA 2.3 0.6
IOL = 12 mA 2.7 0.4
IOL = 16 mA 3.0 0.4
IOL = 24 mA 3.0 0.55
IIInput Leakage Current 0 VI 5.5V 2.3 to 3.6 ±5.0 µA
IOFF Power-Off Leakage Current VI or VO = 5.5V 0.0 10.0 µA
ICC Quiescent Supply Current VI = VCC or GND 2.3 to 3.6 10.0 µA
3.6V VI 5.5V 2.3 to 3.6 ±10.0
ICC Increase in ICC per Input VIH = VCC 0.6V 2.3 to 3.6 500 µA
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74LCX138
AC Electrical Characteristics
Note 6: Skew is def ined as t he absolute va lue of the differenc e betwee n the ac tu al propa gation d elay for any two s eparate outpu ts of the same d evi ce. The
specification a pplies to an y out puts switc hing in the s am e direct ion, either HIGH-t o-LOW (tOSHL) or LOW-to- H IG H (t OSLH).
Dynamic Switching Characteristics
Capacitance
Symbol Parameter
TA = 40°C t o +85°C, RL = 500
Units
VCC = 3.3V ± 0.3V VCC = 2.7V VCC = 2.5V ± 0.2V
CL = 50pF CL = 50pF CL = 30pF
Min Max Min Max Min Max
tPHL Propagation Delay 1.5 6.0 1.5 7.0 1.5 7.2 ns
tPLH An to Qn 1.5 6.0 1.5 7.0 1.5 7.2
tPHL Propagation Delay 1.5 6.5 1.5 7.5 1.5 8.4 ns
tPLH E3 to Qn 1.5 6.5 1.5 7.5 1.5 8.4
tPHL Propagation Delay 1.5 6.0 1.5 7.0 1.5 7.2 ns
tPLH E1 or E2 to Qn 1.5 6.0 1.5 7.0 1.5 7.2
tOSHL Output to Output Skew (Note 6) 1.0 ns
tOSLH 1.0
Symbol Parameter Conditions VCC TA = 25°CUnits
(V) Typical
VOLP Quiet Output Dynamic Peak VOL CL = 50 pF, VIH = 3.3V, VIL = 0V 3.3 0.8 V
CL = 30 pF, VIH = 2.5V, VIL = 0V 2.5 0.6
VOLV Quiet Output Dynamic Valley VOL CL = 50 pF, VIH = 3.3V, VIL = 0V 3.3 0.8 V
CL = 30 pF, VIH = 2.5V, VIL = 0V 2.5 0.6
Symbol Parameter Conditions Typical Units
CIN Input Capacitance VCC = Open, VI = 0V or VCC 7.0 pF
COUT Output Capacitance VCC = 3.3V, VI = 0V or VCC 8.0 pF
CPD Power Dissipation Capacitance VCC = 3.3V, VI = 0V or VCC, f = 10 MHz 25.0 pF
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74LCX138
AC Loading and Waveforms Generic for LCX Family
FIGURE 1. AC Test Circuit
(CL includes probe and jig capa citance)
Waveform for Inverting and Non-Inverting Functions
Prop agation Delay, Pulse Widt h and trec Waveforms
3-STATE Output High Enable and
Disable Times for Logic
3-STATE Output Low Enable and
Disable Times for Logic
Setup Time, Hold TIme and Recovery TIme for Logic
trise and tfall
FIGURE 2. Waveforms
(Input Pul se Characteristics; f = 1MHz, tr = tf = 3ns)
Test Switch
tPLH, tPHL Open
tPZL, tPLZ 6V at VCC = 3.3 V ± 0.3V
VCC x 2 at VCC = 2.5V ± 0.2V
tPZH, tPHZ GND
Symbol VCC
3.3V ± 0.3V 2.7V 2.5V ± 0. 2V
Vmi 1.5V 1.5V VCC/2
Vmo 1.5V 1.5V VCC/2
VxVOL + 0.3V VOL + 0.3V VOL + 0.15V
VyVOH 0.3V VOH 0.3V VOH 0.15V
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74LCX138
Schematic Diagram Generic for LCX Family
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74LCX138
Tape and Reel Specification
Tape Format for DQFN
TAPE DIMENSIONS inches (millimeters)
REEL DIMENSIONS inches (millimeters)
Package Tape Number Cavity Cover Tape
Designator Section Cavities Status Status
Leader (Start End) 125 (typ) Empty Sealed
BQX Carrier 3000 Filled Sealed
Trailer (Hub End) 75 (typ) Empty Sealed
Tape SizeABCDNW1W2
12 mm 13.0 0.059 0.512 0.795 2.165 0.488 0.724
(330.0) (1.50) (13.00) (20.20) (55.00) (12.4) (18.4)
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74LCX138
Physical Dimensions inches (millimeters) unless otherwise noted
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow
Package Number M16A
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74LCX138
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
16-Lead Sma ll Outline Pac kage (SOP), EI AJ TYPE II, 5.3mm Wide
Package Number M16D
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74LCX138
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
16-Terminal Depopulated Quad Very-Thin Flat Pack No Leads (DQFN), JEDEC MO-241, 2.5 x 3.5mm
Package Number MLP016E
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74LCX138 Low Voltage 1-of-8 Decoder/Demultiplexer with 5V Tolerant Inputs
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
Fairchild does not assu me any responsibility for use of any circuitry de scribed, no circuit patent licenses are implied and
Fairchild reserves the right at any time without notice to change said circuitry and specifications.
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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
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to perform when properly used in accordance with
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user.
2. A critical compon ent i n any compon ent of a lif e supp ort
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device or system, or to affect its safety or effectiveness.
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