INDUSTRIAL TEMPERATURE RANGE
IDTQS74FCT251AT
HIGH-SPEED CMOS 8-INPUT MULTIPLEXER
1
FEBRUARY 2001
INDUSTRIAL TEMPERATURE RANGE
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
2001 Integrated Device Technology, Inc.
DSC-5235/1
FEATURES:
CMOS power levels: <7.5mW static
Undershoot clamp diodes on all inputs
True TTL input and output compatibility
Ground bounce controlled outputs
Reduced output swing of 0 to 3.5V
I
OL
= 48mA
Available in SOIC and QSOP packages
FUNCTIONAL BLOCK DIAGRAM
IDTQS74FCT251AT
HIGH-SPEED CMOS
8-INPUT
MULTIPLEXER
DESCRIPTION:
The IDTQS74FCT251T is a high-speed CMOS TTL-compatible 8-input
multiplexer with 3-state outputs. All inputs have clamp diodes for undershoot
noise suppression. All outputs have ground bounce suppression. Outputs
will not load an active bus when Vcc is removed from the device.
Y
E
S2
S1
S0
I0
I1
I2
I3
I4
I5
I6
I7
Y
INDUSTRIAL TEMPERATURE RANGE
2
IDTQS74FCT251AT
HIGH-SPEED CMOS 8-INPUT MULTIPLEXER
PIN CONFIGURATION
Symbol
Description
Max
Unit
V
TERM
Terminal Voltage with Respect to GND
0.5 to +7
V
T
STG
Storage Temperature
65 to +150
C
I
OUT
DC Output Current Max Current Sink/Pin
+120
mA
I
IK
Input Diode Current, V
IN
< 0
-20
mA
I
OK
DC Output Current, V
OUT
< 0
-50
mA
ABSOLUTE MAXIMUM RATINGS
(1)
NOTE:
1. Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause
permanent damage to the device. This is a stress rating only and functional operation
of the device at these or any other conditions above those indicated in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect reliability.
SOIC/ QSOP
TOP VIEW
NOTE:
1. H = HIGH Voltage Level
X = Don't Care
L = LOW Voltage Level
Z = High-Impedance
FUNCTION TABLE
(1)
Select
Outputs
E
S
0
S
1
S
2
Y
Y
Function
H
X
X
X
Z
Z
Disable
L
L
L
L
I
0
I
0
S2-0 = 0
L
L
L
H
I
1
I
1
S2-0 = 1
L
L
H
L
I
2
I
2
S2-0 = 2
L
L
H
H
I
3
I
3
S2-0 = 3
L
H
L
L
I
4
I
4
S2-0 = 4
L
H
L
H
I
5
I
5
S2-0 = 5
L
H
H
L
I
6
I
6
S2-0 = 6
L
H
H
H
I
7
I
7
S2-0 = 7
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
GND
E
I
1
I
0
I
3
I
4
I
5
I
6
I
7
S
0
S
1
S
2
V
CC
I
2
Y
Y
Pin Names
I/O
Description
Ix
I
Data In
S x
I
Select
E
I
Enable
Y, Y
0
Data Out
PIN DESCRIPTION
Symbol
Parameter
(1)
Conditions
Typ.
Max.
Unit
C
IN
Input Capacitance
V
IN
= 0V
4
--
pF
C
OUT
Output Capacitance
V
OUT
= 0V
8
--
pF
CAPACITANCE
(T
A
= +25C, F = 1.0MHz)
NOTE:
1. This parameter is measured at characterization but not tested.
INDUSTRIAL TEMPERATURE RANGE
IDTQS74FCT251AT
HIGH-SPEED CMOS 8-INPUT MULTIPLEXER
3
Symbol
Parameter
Test Conditions
(1)
Min.
Typ.
(2)
Max.
Unit
V
IH
Input HIGH Level
Guaranteed Logic HIGH Level
2
--
--
V
V
IL
Input LOW Level
Guaranteed Logic LOW Level
--
--
0.8
V
V
T
Input Hysteresis
V
TLH
- V
THL
for all inputs
--
0.2
--
V
I
IH
Input HIGH Current
V
CC
= Max.
0
V
IN
V
CC
--
--
5
A
I
IL
Input LOW Current
I
OZ
Off-State Output Current (Hi-Z)
V
CC
= Max.
0
V
IN
V
CC
--
--
5
A
I
OS
Short Circuit Current
V
CC
= Max., V
OUT
= GND
(2)
-60
--
--
mA
V
IC
Input Clamp Voltage
V
CC
= Min., I
IN
= 18mA, T
A
= 25C
--
0.7
1.2
V
V
OH
Output HIGH Voltage
V
CC
= Min.
I
OH
= 15mA
2.4
--
--
V
V
OL
Output LOW Voltage
V
CC
= Min.
I
OL
= 12mA
--
--
0.5
V
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Following Conditions Apply Unless Otherwise Specified:
Industrial: T
A
= 40C to +85C, V
CC
= 5.0V 5%
NOTES:
1. Typical values are at V
CC
= 5.0V, +25C ambient.
2. Not more than one output should be shorted at one time. Duration of the short circuit test should not exceed one second.
Symbol
Parameter
Test Conditions
(1)
Min.
Max.
Unit
I
CC
Quiescent Power Supply Current
V
CC
= Max.
--
1.5
mA
freq = 0
0V
V
IN
0.2V or
V
CC
- 0.2V
V
IN
V
CC
I
CC
Supply Current per Input TTL Inputs HIGH
V
CC
= Max.
--
2
mA
V
IN
= 3.4V
(2)
freq = 0
I
CCD
Supply Current per Input per MHz
V
CC
= Max.
--
0.25
mA/
Outputs Open and Enabled
MHz
One Bit Toggling
50% Duty Cycle
Other inputs at GND or V
CC(3,4)
NOTES:
1. For conditions shown as Min. or Max., use appropriate value specified under DC Electrical Characteristics.
2. Per TTL driven input (V
IN
= 3.4V).
3. For flip-flops, I
CCD
is measured by switching one of the data input pins so that the output changes every clock cycle. This is a measurement of device power consumption
only and does not include power to drive load capacitance or tester capacitance.
4. I
C
= I
QUIESCENT
+ I
INPUTS
+ I
DYNAMIC
I
C
= I
CC
+
I
CC
D
H
N
T
+ I
CCD
(f
CP
/2 + f
i
N
i
)
I
CC
= Quiescent Current
I
CC
= Power Supply Current for a TTL High Input (V
IN
= 3.4V)
D
H
= Duty Cycle for TTL Inputs High
N
T
= Number of TTL Inputs at D
H
I
CCD
= Dynamic Current caused by an Output Transition Pair (HLH or LHL)
f
CP
= Clock Frequency for Register Devices (Zero for Non-Register Devices)
f
i
= Output Frequency
N
i
= Number of Outputs at f
i
All currents are in milliamps and all frequencies are in megahertz.
POWER SUPPLY CHARACTERISTICS
INDUSTRIAL TEMPERATURE RANGE
4
IDTQS74FCT251AT
HIGH-SPEED CMOS 8-INPUT MULTIPLEXER
NOTES:
1. C
LOAD
= 50pF, R
LOAD
= 500
unless otherwise noted.
2. Minimums guaranteed but not tested.
3. This parameter is guaranteed by design but not tested.
Symbol
Parameter
Min.
Max.
Unit
t
IY
Propagation Delay
1.5
5.2
ns
Ix to Y or Y
t
SY
Propagation Delay
1.5
6.6
ns
Sx to Y or Y
t
PZH
Output Enable Time
1.5
6
ns
t
PZL
E to Yx or Y
t
PHZ
Output Disable Time
1.5
6
ns
t
PLZ
E to Yx or Y
SWITCHING CHARACTERISTICS OVER OPERATING RANGE
(1)
INDUSTRIAL TEMPERATURE RANGE
IDTQS74FCT251AT
HIGH-SPEED CMOS 8-INPUT MULTIPLEXER
5
Pulse
Generator
R
T
D.U.T.
V
CC
V
IN
C
L
V
OUT
50pF
500
500
7.0V
3V
1.5V
0V
3V
1.5V
0V
3V
1.5V
0V
3V
1.5V
0V
DATA
INPUT
TIMING
INPUT
ASYNCHRONOUS CONTROL
PRESET
CLEAR
ETC.
SYNCHRONOUS CONTROL
t
SU
t
H
t
REM
t
SU
t
H
HIGH-LOW-HIGH
PULSE
LOW-HIGH-LOW
PULSE
t
W
1.5V
1.5V
SAME PHASE
INPUT TRANSITION
3V
1.5V
0V
1.5V
V
OH
t
PLH
OUTPUT
OPPOSITE PHASE
INPUT TRANSITION
3V
1.5V
0V
t
PLH
t
PHL
t
PHL
V
OL
CONTROL
INPUT
3V
1.5V
0V
3.5V
0V
OUTPUT
NORMALLY
LOW
OUTPUT
NORMALLY
HIGH
SWITCH
CLOSED
SWITCH
OPEN
V
OL
0.3V
0.3V
t
PLZ
t
PZL
t
PZH
t
PHZ
3.5V
0V
1.5V
1.5V
ENABLE
DISABLE
V
OH
PRESET
CLEAR
CLOCK ENABLE
ETC.
FCTL link
FCTL link
FCTL link
FCTL link
FCTL link
TEST CIRCUITS AND WAVEFORMS
Propagation Delay
Test Circuits for All Outputs
Enable and Disable Times
Set-Up, Hold, and Release Times
Pulse Width
NOTES:
1. Diagram shown for input Control Enable-LOW and input Control Disable-HIGH.
2. Pulse Generator for All Pulses: Rate
1.0MHz; t
F
2.5ns; t
R
2.5ns.
Test
Switch
Open Drain
Disable Low
Closed
Enable Low
All Other Tests
Open
SWITCH POSITION
DEFINITIONS:
C
L
= Load capacitance: includes jig and probe capacitance.
R
T
= Termination resistance: should be equal to Z
OUT
of the Pulse Generator.
INDUSTRIAL TEMPERATURE RANGE
6
IDTQS74FCT251AT
HIGH-SPEED CMOS 8-INPUT MULTIPLEXER
ORDERING INFORMATION
CORPORATE HEADQUARTERS
for SALES:
for Tech Support:
2975 Stender Way
800-345-7015 or 408-727-6116
logichelp@idt.com
Santa Clara, CA 95054
fax: 408-492-8674
(408) 654-6459
www.idt.com
IDTQS
XX
FCT
XXXX
XX
Package
Device Type
SO
Q
Small Outline IC (gull wing)
Quarter Size Small Outline Package
High-Speed CMOS 8-Input Multiplexer
251AT
Temp. Range
74
40C to +85C
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