The 74HC643 is an advanced high-speed CMOS
OCTAL BUS TRANSCEIVER (3-STATE)
fabricated with silicon gate C
2
MOS technology.
This IC is intended for two-way asynchronous
communication between data buses, and the
direction of data transmission is determined by
TSSOPDIPSOP
ORDER CODES
PACKAGETUBET & R
DIPM74HC643B1R
SOPM74HC643M1RM74HC643RM13TR
TSSOPM74HC643TTR
DIR input. The enable input G
can be used to
disable the device so that the buses are effectively
isolated.
All inputs are equipped with protection circuits
against static discharge and transient excess
voltage.
PIN CONNECTION AND IEC LOGIC SYMBOLS
1/11August 2001
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M74HC643
INPUT AND OUTPUT EQUIVALENT CIRCUIT PIN DESCRIPTION
PIN NoSYMBOLNAME AND FUNCTION
1DIRDirectional Control
2, 3, 4, 5, 6,
7, 8, 9
18, 17, 16,
15, 14, 13,
12, 11
19G
10GNDGround (0V)
20V
TRUTH TABLE
INPUTSFUNCTIONOUTPUT
A1 to A8Data Inputs/Outputs
B1 to B8Data Inputs/Outputs
CC
Output Enable Input
Positive Supply Voltage
G
LLOUTPUTINPUTA = B
LHINPUTOUTPUTB = A
HXZZZ
X : Don’t Care
Z : High Impedance
LOGIC DIAGRAM
DIRA BUSB BUSYn
This log i c diagram has not be used to esti m ate propagation delays
2/11
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M74HC643
ABSOLUTE MAXIMUM RATINGS
SymbolParameterValueUnit
V
V
V
I
I
OK
I
I
or I
CC
P
T
T
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied
(*) 500mW at 65
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. I
-40 to 85°C -55 to 125°C
= CPD x VCC x fIN + ICC/8 (per circuit)
CC(opr)
Unit
5/11
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M74HC643
TEST CIRCUIT
TESTSWITCH
t
, t
PLH
PHL
, t
t
PZL
PLZ
t
, t
PZH
PHZ
CL = 50pF/150p F or equivalen t (includes j i g and probe capacitance )
R
= 1KΩ or equivalent
1
R
= Z
of pulse generator (typically 50Ω)
T
OUT
Open
V
CC
GND
WAVEFORM 1 : PROPAGATION DELAY TIME (f=1MHz; 50% duty cycle)
6/11
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M74HC643
WAVEFORM 2 : OUTPUT ENABLE AND DISABLE TIME (f=1MHz; 50% duty cycle )
7/11
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M74HC643
Plastic DIP-20 (0.25) MECHANICAL DATA
mm.inch
DIM.
MIN.TYPMAX.MIN.TYP.MAX.
a10.2540.010
B1.391.650.0550.065
b0.450.018
b10.250.010
D25.41.000
E8.50.335
e2.540.100
e322.860.900
F7.10.280
I3.930.155
L3.30.130
Z1.340.053
8/11
P001J
Page 9
SO-20 MECHANICAL DATA
M74HC643
DIM.
MIN.TYPMAX.MIN.TYP.MAX.
A2.650.104
a10.10.20.0040.008
a22.450.096
b0.350.490.0140.019
b10.230.320.0090.012
C0.50.020
c145° (typ.)
D12.6013.000.4960.512
E10.0010.650.3930.419
e1.270.050
e311.430.450
F7.407.600.2910.300
L0.501.270.0200.050
M0.750.029
S8° (max.)
mm.inch
PO13L
9/11
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M74HC643
TSSOP20 MECHANICAL DATA
mm.inch
DIM.
MIN.TYPMAX.MIN.TYP.MAX.
A1.20.047
A10.050.150.0020.0040.006
A20.811.050.0310.0390.041
b0.190.300.0070.012
c0.090.200.0040.0089
D6.46.56.60.2520.2560.260
E6.26.46.60.2440.2520.260
E14.34.44.480.1690.1730.176
e0.65 BSC0.0256 BSC
K0°8°0°8°
L0.450.600.750.0180.0240.030
A2
A
A1
b
e
K
c
L
E
D
E1
PIN 1 IDENTIFICATION
10/11
1
0087225C
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M74HC643
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