DS1487N NSC [National Semiconductor], DS1487N Datasheet

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DS1487N

Manufacturer Part Number
DS1487N
Description
Low Power RS-485 1⁄4 Unit Load Multipoint Transceiver
Manufacturer
NSC [National Semiconductor]
Datasheet

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© 1999 National Semiconductor Corporation
DS1487
Low Power RS-485
General Description
The DS1487 is a low-power transceiver for RS-485 and
RS-422 communication. The device contains one driver and
one receiver. The drivers slew rate allows for operation up to
2.0 Mbps (see Applications Information section). The trans-
ceiver presents
to 128 nodes to be connected together without the use of re-
peaters.
The transceiver draws 200 µA of supply current when un-
loaded or fully loaded with the driver disabled and operates
from a single +5V supply.
The driver is short-circuit current limited and is protected
against excessive power dissipation by thermal shutdown
circuitry that places the driver outputs into TRI-STATE
(High Impedance state) under fault conditions. The driver
guarantees a minimum of 1.5V differential output voltage
with maximum loading across the common mode range
(V
The receiver has a failsafe feature that guarantees a
logic-high output if the input is open circuit.
The DS1487 is available in surface mount and DIP pack-
ages.
Connection and Logic Diagram
*Note: Non Terminated, Open Input only
TRI-STATE
DS1487N
DS1487M
Order Number
OD3
).
®
is a registered trademark of National Semiconductor Corporation.
1
4
unit loading to the RS-485 bus allowing up
0˚C to +70˚C
0˚C to +70˚C
DIP and SOIC
Temp. Range
DS012920-1
DS012920
DIP/N08E
SOP/M08A
1
Package/ ###
4
Unit Load Multipoint Transceiver
®
Features
n Meets TIA/EIA RS-485 multipoint standard
n Allows up to 128 transceivers on the bus (
n Guaranteed full load output voltage (V
n Low quiescent current:
n −7V to +12V common-mode input voltage range
n TRI-STATE outputs on driver and receiver
n AC performance:
n Half-duplex flow through pinout
n Operates from a single 5V supply
n Current-limiting and thermal shutdown for driver
n Pin and functional compatible with MAX1487
Truth Table
X = indeterminate
Z = TRI-STATE
Note 1: Non Terminated, Open Input only
DRIVER SECTION
RECEIVER SECTION
(Note 1)
(Note 1)
overload protection
— Driver transition time: 25 ns typ
— Driver propagation delay: 40 ns typ
— Driver skew: 1 ns typ
— Receiver propagation delay: 200 ns typ
— Receiver skew: 20 ns typ
RE
RE
H
X
X
X
L
L
L
DE
DE
H
H
X
L
L
L
L
OPEN (Note 1)
200 µA typ
DI
H
X
L
+0.2V
−0.2V
A-B
X
OD3
A
H
L
Z
)
1
www.national.com
4
U.L.)
July 1998
RO
B
H
Z
H
Z
H
L
L

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DS1487N Summary of contents

Page 1

... The DS1487 is available in surface mount and DIP pack- ages. Connection and Logic Diagram DIP and SOIC DS012920-1 *Note: Non Terminated, Open Input only Order Number Temp. Range DS1487N 0˚C to +70˚C DS1487M 0˚C to +70˚C TRI-STATE ® registered trademark of National Semiconductor Corporation. © 1999 National Semiconductor Corporation DS012920 ⁄ ...

Page 2

Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage ( Enable Input Voltage (RE (Note 1), DE) −0. Driver Input Voltage (DI) ...

Page 3

Switching Characteristics Over Supply Voltage and Operating Temperature Ranges, unless otherwise specified (Notes Symbol Parameter t Driver Differential Propagation Delay — Low to High PLHD t Driver Differential Propagation Delay — High to Low PHLD t Differential ...

Page 4

Parameter Measurement Information (Continued) FIGURE 4. FIGURE 5. FIGURE 6. *Note: Non Terminated, Open Input only www.national.com DS012920-5 *Note: Non Terminated, Open Input only DS012920-6 DS012920-7 FIGURE 11. 4 DS012920-8 FIGURE 7. DS012920-9 FIGURE 8. DS012920-10 FIGURE 9. DS012920-11 FIGURE ...

Page 5

Parameter Measurement Information *Note: Non Terminated, Open Input only *Note: Non Terminated, Open Input only Pin Descriptions Pin I/O Name # Receiver Output high also if the inputs (A and B) are open (non-terminated). ...

Page 6

Applications Information Due to the multipoint nature of the bus, contention between drivers may occur. This will not cause damage to the drivers since they feature short-circuit protection and also thermal shutdown protection. Thermal shutdown senses die tem- perature and ...

Page 7

... Physical Dimensions inches (millimeters) unless otherwise noted Order Number DS1487N NS Package Number N08E 7 www.national.com ...

Page 8

LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DE- VICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMI- CONDUCTOR CORPORATION. As used herein: 1. Life support devices ...

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