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DM74AS640N

P1-P3P4-P5
© 2000 Fairchild Semiconductor Corporation DS006708 www.fairchildsemi.com
October 1986
Revised March 2000
DM74AS640 3-STATE Octal Bus Transceiver
DM74AS640
3-STATE Octal Bus Transceiver
General Description
This advanced Schottky device contains 8 pairs of 3-
STATE logic elements configured as octal bus transceiver.
This circuit is designed for use in memory, microprocessor
systems and in asynchronous bidirectional data buses.
This device transmits data from the A bus to the B bus, or
vice versa, depending upon the logic level of the direction
control input (DIR). The enable input (G
) can be used to
disable the devices, effecting isolation of buses A and B.
The 3-STATE circuitry also contains a protection feature
that prevents these transceivers from glitching the bus dur-
ing power-up or power-down.
Features
■ Switching specifications at 50 pF
■ Switching specifications guaranteed over full tempera-
ture and V
CC
range
■ Advanced oxide-isolated, ion-implanted Schottky TTL
process
■ Functionally and pin for pin compatible with Schottky,
low power Schottky, and advanced low power Schottky
TTL counterpart
■ Improved AC performance over Schottky, low power
Schottky, and advanced low power Schottky counter-
parts
■ 3-STATE outputs independently controlled on A and B
buses
■ Low output impedance drive to drive terminated trans-
mission lines to 133Ω
■ Specified to interface with CMOS at V
OH
= V
CC
− 2V
Ordering Code:
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
Top View
Function Table
H = HIGH Logic Level
L = LOW Logic Level
X = Immaterial
Logic Diagram
Order Number Package Number Package Description
DM74AS640WM M20B 20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
DM74AS640N N20A 20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Control Inputs
Operation
G
DIR
LLB
Data to A Bus
LHA
Data to B Bus
HX Isolation
www.fairchildsemi.com 2
DM74AS640
Absolute Maximum Ratings(Note 1)
Note 1: 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 “Recommended Operating Conditions” table will define the conditions
for actual device operation.
Recommended Operating Conditions
Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Note 2: All typicals are at V
CC
= 5.0V, T
A
= 25°C.
Note 3: For I/O ports, the parameters I
IH
and I
IL
include the OFF-State output current, I
OZH
and I
OZL
.
Supply Voltage 7V
Input Voltage
Control Inputs 7V
I/O Ports 5.5V
Operating Free Air Temperature Range 0°C to +70°C
Storage Temperature Range −65°C to +150°C
Typical θ
JA
N Package 51.5°C
M Package 69.0°C
Symbol Parameter Min Typ Max Units
V
CC
Supply Voltage 4.5 5 5.5 V
V
IH
HIGH Level Input Voltage 2 V
V
IL
LOW Level Input Voltage 0.8 V
I
OH
HIGH Level Output Current −15 mA
I
OL
LOW Level Output Current 64 mA
T
A
Free Air Operating Temperature 0 70 °C
Symbol Parameter Conditions
Min Typ Max
Units
(Note 2)
V
I
Input Clamp Voltage V
CC
= Min, I
I
= −18 mA −1.2 V
V
OH
HIGH Level V
CC
= 4.5V to 5.5V, I
OH
= −2 mA V
CC
− 2V
Output Voltage V
CC
= 4.5V, I
OH
= −3 mA 2.4 V
V
CC
= 4.5V, I
OH
= Max 2.4 V
V
OL
LOW Level Output Voltage V
CC
= Min, I
OL
= Max 0.35 0.55 V
I
I
Input Current at Max V
CC
= Max, V
I
= 7V,
0.1 mA
Input Voltage (V
I
= 5.5V for A or B Ports)
I
IH
HIGH Level V
CC
= Max Control Inputs 20
µA
Input Current V
I
= 2.7V (Note 3) A or B Ports 70
I
IL
LOW Level V
CC
= Max, Control Inputs −0.5
mA
Input Current V
I
= 0.4V (Note 3) A or B Ports −0.75
I
O
Output Drive Current V
CC
= Max, V
O
= 2.25V −50 −150 mA
I
CCH
Supply Current with Outputs HIGH V
CC
= Max 37 58 mA
I
CCL
Supply Current with Outputs LOW 78 123 mA
I
CCZ
Supply Current with Outputs
51 80 mA
in 3-STATE
3 www.fairchildsemi.com
DM74AS640
Switching Characteristics
over recommended operating free air temperature range (unless otherwise noted)
From To
V
CC
= Min to Max,
Symbol Parameter (Input) (Output)
C
L
= 50 pF, R
1
= R
2
= 500Ω
Units
Min Max
t
PLH
Propagation Delay Time
A or B B or A 2 7 ns
LOW-to-HIGH Level Output
t
PHL
Propagation Delay Time
A or B B or A 2 6 ns
HIGH-to-LOW Level Output
t
PZH
Output Enable Time to
G A or B 2 8 ns
HIGH Level Output
t
PZL
Output Enable Time to
G A or B 2 10 ns
LOW Level Output
t
PHZ
Output Disable Time from
G A or B 2 8 ns
HIGH Level Output
t
PLZ
Output Disable Time from
G A or B 2 13 ns
LOW Level Output
P1-P3P4-P5

DM74AS640N

Mfr. #:
Buy DM74AS640N
Manufacturer:
ON Semiconductor / Fairchild
Description:
Bus Transceivers Oct 3-STATE Oct Tran
Lifecycle:
New from this manufacturer.
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