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Teilenummer | DM74AS640 |
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Beschreibung | 3-STATE Octal Bus Transceiver | |
Hersteller | Fairchild Semiconductor | |
Logo | ||
Gesamt 5 Seiten October 1986
Revised March 2000
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
s Switching specifications at 50 pF
s Switching specifications guaranteed over full tempera-
ture and VCC range
s Advanced oxide-isolated, ion-implanted Schottky TTL
process
s Functionally and pin for pin compatible with Schottky,
low power Schottky, and advanced low power Schottky
TTL counterpart
s Improved AC performance over Schottky, low power
Schottky, and advanced low power Schottky counter-
parts
s 3-STATE outputs independently controlled on A and B
buses
s Low output impedance drive to drive terminated trans-
mission lines to 133Ω
s Specified to interface with CMOS at VOH = VCC − 2V
Ordering Code:
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
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
Function Table
Control Inputs
G DIR
LL
L
H
H = HIGH Logic Level
L = LOW Logic Level
X = Immaterial
H
X
Logic Diagram
Operation
B Data to A Bus
A Data to B Bus
Isolation
Top View
© 2000 Fairchild Semiconductor Corporation DS006708
www.fairchildsemi.com
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Seiten | Gesamt 5 Seiten | |
PDF Download | [ DM74AS640 Schematic.PDF ] |
Teilenummer | Beschreibung | Hersteller |
DM74AS640 | 3-STATE Octal Bus Transceiver | Fairchild Semiconductor |
DM74AS640N | 3-STATE Octal Bus Transceiver | Fairchild Semiconductor |
DM74AS640WM | 3-STATE Octal Bus Transceiver | Fairchild Semiconductor |
DM74AS646 | Octal Bus Transceiver and Register | Fairchild Semiconductor |
DM74AS646NT | Octal Bus Transceiver and Register | Fairchild Semiconductor |
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