IDT74FCT138AT/CT
FAST CMOS 1-OF-8 DECODER WITH ENABLE
INDUSTRIAL TEMPERATURE RANGE
FAST CMOS
1-OF-8 DECODER
WITH ENABLE
FEATURES:
•
•
•
•
A and C grades
Low input and output leakage
≤
1µA (max.)
CMOS power levels
True TTL input and output compatibility:
– V
OH
= 3.3V (typ.)
– V
OL
= 0.3V (typ.)
High Drive outputs (-15mA I
OH
, 48mA I
OL
)
Meets or exceeds JEDEC standard 18 specifications
Power off disable outputs permit "live insertion"
Available in SOIC and QSOP packages
IDT74FCT138AT/CT
DESCRIPTION:
The IDT74FCT138T is a 1-of-8 decoder built using an advanced dual
metal CMOS technology. The IDT54/74FCT138T accepts three binary
weighted inputs (A
0
, A
1
, A
2
) and, when enabled, provides eight mutually
exclusive active low outputs (O
0
-
O
7
). The IDT54/74FCT138T features
three enable inputs, two active low (E
1
,
E
2
) and one active high (E
3
). All
outputs will be high unless
E
1
and
E
2
are low and E
3
is high. This multiple
enable function allows easy parallel expansion of the device to a 1-of-32
(5 lines to 32 lines) decoder with just four IDT54/74FCT138T devices and
one inverter.
•
•
•
•
FUNCTIONAL BLOCK DIAGRAM
A
2
A
1
A
0
E
1
E
2
E
3
O
7
O
6
O
5
O
4
O
3
O
2
O
1
O
0
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
INDUSTRIAL TEMPERATURE RANGE
1
FEBRUARY 2006
DSC-2570/11
© 2006 Integrated Device Technology, Inc.
IDT74FCT138AT/CT
FAST CMOS 1-OF-8 DECODER WITH ENABLE
INDUSTRIAL TEMPERATURE RANGE
PIN CONFIGURATION
ABSOLUTE MAXIMUM RATINGS
(1)
Symbol
V
TERM
(2)
V
TERM
(3)
Description
Terminal Voltage with Respect to GND
Terminal Voltage with Respect to GND
Storage Temperature
DC Output Current
Max
–0.5 to +7
–0.5 to V
CC
+0.5
–65 to +150
–60 to +120
Unit
V
V
°C
mA
A
0
A
1
A
2
E
1
E
2
E
3
O
7
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
SOIC/ QSOP
TOP VIEW
V
CC
O
0
O
1
O
2
O
3
O
4
O
5
O
6
T
STG
I
OUT
NOTES:
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. No terminal voltage may exceed
Vcc by =0.5V unless otherwise noted.
2. Inputs and Vcc terminals only.
3. Output and I/O terminals only.
CAPACITANCE
(T
A
= +25°C, F = 1.0MHz)
Symbol
C
IN
C
OUT
Parameter
(1)
Input Capacitance
Output Capacitance
Conditions
V
IN
= 0V
V
OUT
= 0V
Typ.
6
8
Max.
10
12
Unit
pF
pF
NOTE:
1. This parameter is measured at characterization but not tested.
PIN DESCRIPTION
Pin Names
A
0
- A
2
E
1
,
E
2
E
3
O
0
-
O
7
Address Inputs
Enable Inputs (Active LOW)
Enable Input (Active HIGH)
Outputs (Active LOW)
Description
2
IDT74FCT138AT/CT
FAST CMOS 1-OF-8 DECODER WITH ENABLE
INDUSTRIAL TEMPERATURE RANGE
FUNCTION TABLE
(1)
Inputs
E
1
H
X
X
L
L
L
L
L
L
L
L
E
2
X
H
X
L
L
L
L
L
L
L
L
E
3
X
X
L
H
H
H
H
H
H
H
H
A
0
X
X
X
L
H
L
H
L
H
L
H
A
1
X
X
X
L
L
H
H
L
L
H
H
A
2
X
X
X
L
L
L
L
H
H
H
H
O
0
H
H
H
L
H
H
H
H
H
H
H
O
1
H
H
H
H
L
H
H
H
H
H
H
O
2
H
H
H
H
H
L
H
H
H
H
H
Outputs
O
3
O
4
H
H
H
H
H
H
H
H
H
H
H
H
L
H
H
L
H
H
H
H
H
H
O
5
H
H
H
H
H
H
H
H
L
H
H
O
6
H
H
H
H
H
H
H
H
H
L
H
O
7
H
H
H
H
H
H
H
H
H
H
L
NOTE:
1. H = HIGH Voltage Level
X = Don’t Care
L = LOW Voltage Level
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Following Conditions Apply Unless Otherwise Specified:
Industrial: T
A
= –40°C to +85°C, V
CC
= 5.0V ±10%
Symbol
V
IH
V
IL
I
IH
I
IL
I
I
V
IK
I
OS
V
OH
V
OL
V
H
I
CC
Parameter
Input HIGH Level
Input LOW Level
Input HIGH Current
(4)
Input LOW Current
(4)
Input HIGH Current
(4)
Clamp Diode Voltage
Short Circuit Current
Output HIGH Voltage
Output LOW Voltage
Input Hysteresis
Quiescent Power Supply Current
V
CC
= Max.
V
IN
= GND or V
CC
Test Conditions
(1)
Guaranteed Logic HIGH Level
Guaranteed Logic LOW Level
V
CC
= Max.
V
CC
= Max.
V
CC
= Max., V
I
= V
CC
(Max.)
V
CC
= Min., I
IN
= –18mA
V
CC
= Max., V
O
= GND
(3)
V
CC
= Min
V
IN
= V
IH
or V
IL
V
CC
= Min
V
IN
= V
IH
or V
IL
—
I
OH
= –8mA
I
OH
= –15mA
I
OL
= –48mA
V
I
= 2.7V
V
I
= 0.5V
Min.
2
—
—
—
—
—
–60
2.4
2
—
—
—
Typ.
(2)
—
—
—
—
—
–0.7
–120
3.3
3
0.3
200
0.01
Max.
—
0.8
±1
±1
±1
–1.2
–225
—
—
0.5
—
1
V
mV
mA
µA
V
mA
V
Unit
V
V
µA
NOTES:
1. For conditions shown as Min. or Max., use appropriate value specified under Electrical Characteristics for the applicable device type.
2. Typical values are at V
CC
= 5.0V, +25°C ambient.
3. Not more than one output should be tested at one time. Duration of the test should not exceed one second.
4. The test limit for this parameter is ±5µA at T
A
= –55°C.
3
IDT74FCT138AT/CT
FAST CMOS 1-OF-8 DECODER WITH ENABLE
INDUSTRIAL TEMPERATURE RANGE
POWER SUPPLY CHARACTERISTICS
Symbol
ΔI
CC
I
CCD
Parameter
Quiescent Power Supply Current
TTL Inputs HIGH
Dynamic Power Supply
Current
(4)
V
CC
= Max.
V
IN
= 3.4V
(3)
V
CC
= Max.
Outputs Open
One Input Toggling
50% Duty Cycle
V
CC
= Max.
Outputs Open
Toggle
E
1
,
E
2
, or E
3
50% Duty Cycle
fo = 10MHz
One Input and
One Output Toggling
NOTES:
1. For conditions shown as Min. or Max., use appropriate value specified under Electrical Characteristics for the applicable device type.
2. Typical values are at V
CC
= 5.0V, +25°C ambient.
3. Per TTL driven input; (V
IN
= 3.4V). All other inputs at V
CC
or GND.
4. This parameter is not directly testable, but is derived for use in Total Power Supply Calculations.
5. I
C
= I
QUIESCENT
+ I
INPUTS
+ I
DYNAMIC
I
C
= I
CC
+
ΔI
CC
D
H
N
T
+ I
CCD
(f
O
N
O
)
I
CC
= Quiescent Current
ΔI
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 Input Transition Pair (HLH or LHL)
f
O
= Output Frequency
N
O
= Number of Outputs at f
O
All currents are in milliamps and all frequencies are in megahertz.
Test Conditions
(1)
Min.
—
Typ.
(2)
0.5
0.15
Max.
2
0.3
Unit
mA
mA/
MHz
V
IN
= V
CC
V
IN
= GND
—
I
C
Total Power Supply Current
(5)
V
IN
= V
CC
V
IN
= GND
V
IN
= 3.4V
V
IN
= GND
—
1.5
4
mA
—
1.8
5
SWITCHING CHARACTERISTICS OVER OPERATING RANGE
74FCT138AT
Symbol
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
Parameter
Propagation Delay
Ax to
Ox
Propagation Delay
E
1
or
E
2
to
Ox
Propagation Delay
E
3
to
Ox
Condition
C
L
= 50pF
R
L
= 500Ω
(1)
74FCT138CT
Max.
5.8
5.9
5.9
Min.
1.5
1.5
1.5
(2)
Min.
1.5
1.5
1.5
(2)
Max.
5.1
5.2
5.2
Unit
ns
ns
ns
NOTES:
1. See test circuit and waveforms.
2. Minimum limits are guaranteed but not tested on Propagation Delays.
4
IDT74FCT138AT/CT
FAST CMOS 1-OF-8 DECODER WITH ENABLE
INDUSTRIAL TEMPERATURE RANGE
TEST CIRCUITS AND WAVEFORMS
V
CC
500W
V
IN
Pulse
Generator
R
T
D.U.T
.
V
OUT
7.0V
SWITCH POSITION
Test
Open Drain
Disable Low
Enable Low
All Other Tests
Switch
Closed
Open
50pF
C
L
500W
DEFINITIONS:
C
L
= Load capacitance: includes jig and probe capacitance.
R
T
= Termination resistance: should be equal to Z
OUT
of the Pulse Generator.
Octal Link
Test Circuits for All Outputs
DATA
INPUT
TIMING
INPUT
ASYNCHRONOUS CONTROL
PRESET
CLEAR
ETC.
SYNCHRONOUS CONTROL
PRESET
CLEAR
CLOCK ENABLE
ETC.
t
SU
t
H
t
REM
3V
1.5V
0V
3V
1.5V
0V
3V
1.5V
0V
3V
1.5V
0V
LOW-HIGH-LOW
PULSE
t
W
HIGH-LOW-HIGH
PULSE
1.5V
1.5V
t
SU
t
H
Pulse Width
Octal Link
Octal Link
Set-Up, Hold, and Release Times
ENABLE
SAME PHASE
INPUT TRANSITION
t
PLH
OUTPUT
t
PLH
OPPOSITE PHASE
INPUT TRANSITION
t
PHL
t
PHL
3V
1.5V
0V
V
OH
1.5V
V
OL
3V
1.5V
0V
CONTROL
INPUT
t
PZL
OUTPUT
NORMALLY
LOW
OUTPUT
NORMALLY
HIGH
SWITCH
CLOSED
t
PZH
SWITCH
OPEN
1.5V
0V
3.5V
1.5V
t
PHZ
DISABLE
3V
1.5V
0V
3.5V
0.3V
0.3V
V
OL
V
OH
0V
Octal Link
t
PLZ
Octal Link
Propagation Delay
Enable and Disable Times
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.
5
Microchip MCU
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
