STMICROELECTRONICS 74AC240B

74AC240
OCTAL BUS BUFFER
WITH 3 STATE OUTPUTS (INVERTED)
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HIGH SPEED: tPD = 4.2ns (TYP.) at VCC = 5V
LOW POWER DISSIPATION:
ICC = 4µA(MAX.) at TA=25°C
HIGH NOISE IMMUNITY:
VNIH = V NIL = 28 % VCC (MIN.)
50Ω TRANSMISSION LINE DRIVING
CAPABILITY
SYMMETRICAL OUTPUT IMPEDANCE:
|IOH| = IOL = 24mA (MIN)
BALANCED PROPAGATION DELAYS:
tPLH ≅ tPHL
OPERATING VOLTAGE RANGE:
VCC (OPR) = 2V to 6V
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 240
IMPROVED LATCH-UP IMMUNITY
DESCRIPTION
The 74AC240 is an advanced high-speed CMOS
OCTAL BUS BUFFER (3-STATE) fabricated with
sub-micron silicon gate and double-layer metal
wiring C2MOS tecnology.
G control input governs four BUS BUFFERs.
DIP
SOP
TSSOP
ORDER CODES
PACKAGE
TUBE
DIP
SOP
TSSOP
74AC240B
74AC240M
T&R
74AC240MTR
74AC240TTR
This device is designed to be used with 3 state
memory address drivers, etc.
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
PIN CONNECTION AND IEC LOGIC SYMBOLS
April 2001
1/9
74AC240
INPUT AND OUTPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
PIN No
SYMBOL
1
2, 4, 6, 8
9, 7, 5, 3
11, 13, 15,
17
18, 16, 14,
12
19
10
20
1G
1A1 to 1A4
2Y1 to 2Y4
2A1 to 2A4
Output Enable Input
Data Inputs
Data Outputs
Data Inputs
1Y1 to 1Y4
Data Outputs
2G
GND
VCC
NAME AND FUNCTION
Output Enable Input
Ground (0V)
Positive Supply Voltage
TRUTH TABLE
INPUTS
OUTPUT
G
An
Yn
L
L
H
L
H
X
H
L
Z
X : Don’t Care
Z : High Impedance
ABSOLUTE MAXIMUM RATINGS
Symbol
VCC
Parameter
Supply Voltage
Value
Unit
-0.5 to +7
V
VI
DC Input Voltage
-0.5 to VCC + 0.5
V
VO
DC Output Voltage
IIK
DC Input Diode Current
-0.5 to VCC + 0.5
± 20
mA
IOK
DC Output Diode Current
± 20
mA
IO
DC Output Current
± 50
mA
ICC or IGND DC VCC or Ground Current
Tstg
Storage Temperature
TL
Lead Temperature (10 sec)
V
± 400
mA
-65 to +150
°C
300
°C
Absolute Maximum Ratings are those values beyond which damage to the device may occour. Functional operation under these conditions
is not implied.
RECOMMENDED OPERATING CONDITIONS
Symbol
VCC
Parameter
Supply Voltage
Unit
2 to 6
V
VI
Input Voltage
0 to VCC
V
VO
Output Voltage
0 to VCC
V
Top
Operating Temperature
dt/dv
Input Rise and Fall Time VCC = 3.0, 4.5 or 5.5V (note 1)
1) VIN from 30% to 70% of V CC
2/9
Value
-55 to 125
°C
8
ns/V
74AC240
DC SPECIFICATIONS
Test Condition
Symbol
VIH
VIL
VOH
VOL
II
Ioz
ICC
IOLD
IOHD
Parameter
High Level Input
Voltage
Low Level Input
Voltage
High Level Output
Voltage
Low Level Output
Voltage
Input Leakage
Current
High Impedance
Output Leakage
Current
Quiescent Supply
Current
Dynamic Output
Current (note 1, 2)
TA = 25°C
VCC
(V)
3.0
4.5
5.5
3.0
4.5
5.5
Value
VO = 0.1 V or
VCC-0.1V
Min.
Typ.
2.1
3.15
3.85
1.5
2.25
2.75
1.5
2.25
2.75
VO = 0.1 V or
VCC-0.1V
Max.
-40 to 85°C
-55 to 125°C
Min.
Min.
Max.
2.1
3.15
3.85
0.9
1.35
1.65
Max.
2.1
3.15
3.85
0.9
1.35
1.65
V
0.9
1.35
1.65
3.0
IO=-50 µA
2.9
2.99
2.9
2.9
4.5
IO=-50 µA
4.4
4.49
4.4
4.4
5.49
5.5
IO=-50 µA
5.4
5.4
5.4
3.0
IO=-12 mA
2.56
2.46
2.4
4.5
IO=-24 mA
3.86
3.76
3.7
5.5
IO=-24 mA
4.86
4.76
4.7
Unit
V
V
3.0
IO=50 µA
0.002
0.1
0.1
0.1
4.5
IO=50 µA
0.001
0.1
0.1
0.1
5.5
IO=50 µA
0.001
0.1
0.1
0.1
3.0
IO=12 mA
0.36
0.44
0.5
4.5
IO=24 mA
0.36
0.44
0.5
5.5
IO=24 mA
0.36
0.44
0.5
5.5
VI = VCC or GND
± 0.1
±1
±1
µA
5.5
VI = VIH or VIL
VO = VCC or GND
± 0.5
± 2.5
±5
µA
5.5
VI = VCC or GND
4
40
80
µA
VOLD = 1.65 V max
75
50
mA
VOHD = 3.85 V min
-75
-50
mA
5.5
V
1) Maximum test duration 2ms, one output loaded at time
2) Incident wave switching is guaranteed on transmission lines with impedances as low as 50Ω
3/9
74AC240
AC ELECTRICAL CHARACTERISTICS (CL = 50 pF, RL = 500 Ω, Input tr = tf = 3ns)
Test Condition
Symbol
Parameter
tPLH tPHL Propagation Delay
Time
tPZL tPZH Output Enable
Time
tPLZ tPHZ Output Disable
Time
Value
TA = 25°C
VCC
(V)
-40 to 85°C
-55 to 125°C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
(*)
1.5
5.7
8.0
1.5
9.0
1.5
11.0
(**)
5.0
1.5
4.2
6.5
1.5
7.0
1.5
8.5
3.3(*)
1.5
7.0
10.5
1.5
11.0
1.5
13.0
5.0(**)
1.5
5.0
8.0
1.5
8.5
1.5
10.5
3.3(*)
1.5
7.0
10.5
1.5
11.5
1.5
13.5
(**)
1.5
6.5
9.0
1.5
9.5
1.5
11.0
3.3
5.0
Unit
ns
ns
ns
(*) Voltage range is 3.3V ± 0.3V
(**) Voltage range is 5.0V ± 0.5V
CAPACITIVE CHARACTERISTICS
Test Condition
Symbol
Parameter
CIN
Input Capacitance
COUT
Output
Capacitance
Power Dissipation
Capacitance (note
1)
CPD
TA = 25°C
VCC
(V)
Min.
5.0
Typ.
Max.
-40 to 85°C
-55 to 125°C
Min.
Min.
Max.
pF
pF
9
fIN = 10MHz
Unit
Max.
5
5.0
5.0
Value
21
pF
1) CPD is defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without
load. (Refer to Test Circuit). Average operating current can be obtained by the following equation. ICC(opr) = CPD x VCC x f IN + ICC/8 (per circuit)
TEST CIRCUIT
TEST
SWITCH
tPLH, tPHL
Open
tPZL, tPLZ
2VCC
tPZH, tPHZ
Open
CL = 50pF or equivalent (includes jig and probe capacitance)
RL = R1 = 500Ω or equivalent
RT = ZOUT of pulse generator (typically 50Ω)
4/9
74AC240
WAVEFORM 1: PROPAGATION DELAYS (f=1MHz; 50% duty cycle)
WAVEFORM 2: OUTPUT ENABLE AND DISABLE TIME (f=1MHz; 50% duty cycle)
5/9
74AC240
Plastic DIP-20 (0.25) MECHANICAL DATA
mm
DIM.
MIN.
a1
0.254
B
1.39
TYP.
inch
MAX.
MIN.
TYP.
MAX.
0.010
1.65
0.055
0.065
b
0.45
0.018
b1
0.25
0.010
D
25.4
1.000
E
8.5
0.335
e
2.54
0.100
e3
22.86
0.900
F
7.1
0.280
I
3.93
0.155
L
Z
3.3
0.130
1.34
0.053
P001J
6/9
74AC240
SO-20 MECHANICAL DATA
mm
DIM.
MIN.
TYP.
A
a1
inch
MAX.
MIN.
TYP.
2.65
0.10
0.104
0.20
a2
MAX.
0.004
0.007
2.45
0.096
b
0.35
0.49
0.013
0.019
b1
0.23
0.32
0.009
0.012
C
0.50
0.020
c1
45 (typ.)
D
12.60
13.00
0.496
0.512
E
10.00
10.65
0.393
0.419
e
1.27
0.050
e3
11.43
0.450
F
7.40
7.60
0.291
0.299
L
0.50
1.27
0.19
0.050
M
S
0.75
0.029
8 (max.)
P013L
7/9
74AC240
TSSOP20 MECHANICAL DATA
mm
DIM.
MIN.
inch
TYP.
MAX.
A
MIN.
TYP.
1.1
0.433
A1
0.05
0.10
0.15
0.002
0.004
0.006
A2
0.85
0.9
0.95
0.335
0.354
0.374
b
0.19
0.30
0.0075
0.0118
c
0.09
0.2
0.0035
0.0079
D
6.4
6.5
6.6
0.252
0.256
0.260
E
6.25
6.4
6.5
0.246
0.252
0.256
E1
4.3
4.4
4.48
0.169
0.173
0.176
e
0.65 BSC
0.0256 BSC
K
0o
4o
8o
0o
4o
8o
L
0.50
0.60
0.70
0.020
0.024
0.028
A
A2
A1
b
K
e
E1
PIN 1 IDENTIFICATION
1
L
E
c
D
8/9
MAX.
74AC240
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from
its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications
mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information
previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or
systems without express written approval of STMicroelectronics.
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