2003 Fairchild Semiconductor Corporation
DS500386
www.fairchildsemi.com
September 2000
Revised July 2003
7
4
LCX126
Low V
o
lt
age
Quad Buff
er wit
h
5V T
o
ler
a
nt
I
nputs and O
u
tput
s
74LCX126
Low Voltage Quad Buffer
with 5V Tolerant Inputs and Outputs
General Description
The LCX126 contains four independent non-inverting buff-
ers with 3-STATE outputs. Each output is disabled when
the associated output-enable (OE) input is LOW. The
inputs tolerate voltages up to 7V allowing the interface of
5V systems to 3V systems.
The 74LCX126 is fabricated with an advanced CMOS tech-
nology to achieve high speed operation while maintaining
CMOS low power dissipation.
Features
s
5V tolerant inputs and outputs
s
2.3V3.6V V
CC
specifications provided
s
5.5 ns t
PD
max (V
CC
=
3.3V), 10
A I
CC
max
s
Power down high impedance inputs and outputs
s
Supports live insertion/withdrawal (Note 1)
s
24 mA output drive (V
CC
=
3.0V)
s
Implements patented noise/EMI reduction circuitry
s
Latch-up performance exceeds 500 mA
s
ESD performance:
Human body model
>
2000V
Machine model
>
100V
Note 1: To ensure the high-impedance state during power up or down, OE
should be tied to GND through a pull-up resistor: the minimum value or the
resistor is determined by the current-sourcing capability of the driver.
Ordering Code:
Device also available in Tape and Reel. Specify by appending suffix letter "X" to the ordering code.
Logic Symbol
IEEE/IEC
Pin Descriptions
Connection Diagram
Truth Table
H
=
HIGH Voltage Level
Z
=
High Impedance
L
=
LOW Voltage Level
X
=
Immaterial
Order Number
Package Number
Package Description
74LCX126M
M14A
14-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150" Narrow
74LCX126SJ
M14D
14-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
74LCX126MTC
MTC14
14-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
Pin Names
Description
A
n
Inputs
OE
n
Output Enable Inputs
O
n
Outputs
Inputs
Output
OE
n
A
n
O
n
H
L
L
H
H
H
L
X
Z
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2
74LCX126
Absolute Maximum Ratings
(Note 2)
Recommended Operating Conditions
(Note 4)
Note 2: 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-
mended Operating Conditions" table will define the conditions for actual device operation.
Note 3: I
O
Absolute Maximum Rating must be observed.
Note 4: Unused inputs or I/Os must be held HIGH or LOW. They may not float.
DC Electrical Characteristics
Symbol
Parameter
Value
Conditions
Units
V
CC
Supply Voltage
-
0.5 to
+
7.0
V
V
I
DC Input Voltage
-
0.5 to
+
7.0
V
V
O
DC Output Voltage
-
0.5 to
+
7.0
Output in 3-STATE
V
-
0.5 to V
CC
+
0.5
Output in HIGH or LOW State (Note 3)
V
I
IK
DC Input Diode Current
-
50
V
I
<
GND
mA
I
OK
DC Output Diode Current
-
50
V
O
<
GND
mA
+
50
V
O
>
V
CC
I
O
DC Output Source/Sink Current
50
mA
I
CC
DC Supply Current per Supply Pin
100
mA
I
GND
DC Ground Current per Ground Pin
100
mA
T
STG
Storage Temperature
-
65 to
+
150
C
Symbol
Parameter
Min
Max
Units
V
CC
Supply Voltage
Operating
2.0
3.6
V
Data Retention
1.5
3.6
V
I
Input Voltage
0
5.5
V
V
O
Output Voltage
HIGH or LOW State
0
V
CC
V
3-STATE
0
5.5
I
OH
/I
OL
Output Current
V
CC
=
3.0V
-
3.6V
24
mA
V
CC
=
2.7V
-
3.0V
12
V
CC
=
2.3V
-
2.7V
8
T
A
Free-Air Operating Temperature
-
40
85
C
t/
V
Input Edge Rate, V
IN
=
0.8V2.0V, V
CC
=
3.0V
0
10
ns/V
Symbol
Parameter
Conditions
V
CC
T
A
=
-
40
C to
+
85
C
Units
(V)
Min
Max
V
IH
HIGH Level Input Voltage
2.3
-
2.7
1.7
V
2.7
-
3.6
2.0
V
IL
LOW Level Input Voltage
2.3
-
2.7
0.7
V
2.7
-
3.6
0.8
V
OH
HIGH Level Output Voltage
I
OH
=
-
100
A
2.3
-
3.6
V
CC
-
0.2
V
I
OH
= -8 mA
2.3
1.8
I
OH
=
-
12 mA
2.7
2.2
I
OH
=
-
18 mA
3.0
2.4
I
OH
=
-
24 mA
3.0
2.2
V
OL
LOW Level Output Voltage
I
OL
=
100
A
2.3
-
3.6
0.2
V
I
OL
= 8mA
2.3
0.6
I
OL
=
12 mA
2.7
0.4
I
OL
=
16 mA
3.0
0.4
I
OL
=
24 mA
3.0
0.55
I
I
Input Leakage Current
0
V
I
5.5V
2.3
-
3.6
5.0
A
I
OZ
3-STATE Output Leakage
0
V
O
5.5V
2.3
-
3.6
5.0
A
V
I
=
V
IH
or V
IL
I
OFF
Power-Off Leakage Current
V
I
or V
O
=
5.5V
0
10
A
3
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7
4
LCX126
DC Electrical Characteristics
(Continued)
Note 5: Outputs disabled or 3-STATE only.
AC Electrical Characteristics
Note 6: Skew is defined as the absolute value of the difference between the actual propagation delay for any two separate outputs of the same device. The
specification applies to any outputs switching in the same direction, either HIGH-to-LOW (t
OSHL
) or LOW-to-HIGH (t
OSLH
).
Dynamic Switching Characteristics
Capacitance
Symbol
Parameter
Conditions
V
CC
T
A
=
-
40
C to
+
85
C
Units
(V)
Min
Max
I
CC
Quiescent Supply Current
V
I
=
V
CC
or GND
2.3
-
3.6
10
A
3.6V
V
I
, V
O
5.5V (Note 5)
2.3
-
3.6
10
I
CC
Increase in I
CC
per Input
V
IH
=
V
CC
-
0.6V
2.3
-
3.6
500
A
Symbol
Parameter
T
A
=
-
40
C to
+
85
C, R
L
=
500
Units
V
CC
=
3.3V
0.3V
V
CC
=
2.7V
V
CC
=
2.5V
0.2V
C
L
=
50 pF
C
L
=
50 pF
C
L
=
30 pF
Min
Max
Min
Max
Min
Max
t
PHL
Propagation Delay
1.5
5.5
1.5
6.0
1.5
6.6
ns
t
PLH
1.5
5.5
1.5
6.0
1.5
6.6
t
PZL
Output Enable Time
1.5
6.0
1.5
7.0
1.5
7.8
ns
t
PZH
1.5
6.0
1.5
7.0
1.5
7.8
t
PLZ
Output Disable Time
1.5
5.5
1.5
6.5
1.5
6.6
ns
t
PHZ
1.5
5.5
1.5
6.5
1.5
6.6
t
OSHL
Output to Output Skew (Note 6)
1.0
ns
t
OSLH
1.0
Symbol
Parameter
Conditions
V
CC
T
A
=
25
C
Units
(V)
Typical
V
OLP
Quiet Output Dynamic Peak V
OL
C
L
=
50 pF, V
IH
=
3.3V, V
IL
=
0V
3.3
0.8
V
C
L
=
30 pF, V
IH
=
2.5V, V
IL
=
0V
2.5
0.6
V
OLV
Quiet Output Dynamic Valley V
OL
C
L
=
50 pF, V
IH
=
3.3V, V
IL
=
0V
3.3
-
0.8
V
C
L
=
30 pF, V
IH
=
2.5V, V
IL
=
0V
2.5
-
0.6
Symbol
Parameter
Conditions
Typical
Units
C
IN
Input Capacitance
V
CC
=
Open, V
I
=
0V or V
CC
7
pF
C
OUT
Output Capacitance
V
CC
=
3.3V, V
I
=
0V or V
CC
8
pF
C
PD
Power Dissipation Capacitance
V
CC
=
3.3V, V
I
=
0V or V
CC
, f
=
10 MHz
25
pF
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4
74LCX126
AC Loading and Waveforms
Generic for LCX Family
FIGURE 1. AC Test Circuit
(C
L
includes probe and jig capacitance)
Waveform for Inverting and Non-Inverting Functions
Propagation Delay, Pulse Width and t
rec
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
t
rise
and t
fall
FIGURE 2. Waveforms
(Input Pulse Characteristics; f = 1MHz, t
r
= t
f
= 3ns)
Test
Switch
t
PLH
, t
PHL
Open
t
PZL
, t
PLZ
6V at V
CC
=
3.3
0.3V
V
CC
x 2 at V
CC
=
2.5
0.2V
t
PZH
,t
PHZ
GND
Symbol
V
CC
3.3V
0.3V
2.7V
2.5V
0.2V
V
mi
1.5V
1.5V
V
CC
/2
V
mo
1.5V
1.5V
V
CC
/2
V
x
V
OL
+
0.3V
V
OL
+
0.3V
V
OL
+
0.15V
V
y
V
OH
-
0.3V
V
OH
-
0.3V
V
OH
-
0.15V
5
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7
4
LCX126
Schematic Diagram
Generic for LCX Family
PDF 
ZIP