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Details, datasheet, quote on part number:LMS485IMX
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| Part: | LMS485IMX |
| Category: | Interface and Interconnect => RS-485 |
| Description: | LMS485 - 5V Low Power RS-485 / RS-422 Differential Bus Transceiver, Package: Soic Narrow, Pin Nb=8 |
| Company: | National Semiconductor Corporation |
| Datasheet: | Download LMS485IMX datasheet File size : 256 kB |
| Request For quote: | Find where to buy LMS485IMX
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Datasheet text preview:
LMS485 5V Low Power RS-485 / RS-422 Differential Bus Transceiver
April 2003
LMS485 5V Low Power RS-485 / RS-422 Differential Bus Transceiver
General Description
The LMS485 is a low power differential bus/line transceiver designed for high speed bidirectional data communication on multipoint bus transmission lines. It is designed for balanced transmission lines. It meets ANSI Standards TIA/EIA RS422-B, TIA/EIA RS485-A and ITU recommendation and V.11 and X.27. The LMS485 combines a TRI-STATETM differential line driver and differential input receiver, both of which operate from a single 5.0V power supply. The driver and receiver have an active high and active low, respectively, that can be externally connected to function as a direction control. The driver and receiver differential inputs are internally connected to form differential input/output (I/O) bus ports that are designed to offer minimum loading to bus whenever the driver is disabled or when VCC = 0V. These ports feature wide positive and negative common mode voltage ranges, making the device suitable for multipoint applications in noisy environments. The LMS485 is available in a 8-Pin SOIC and 8-Pin DIP packages. It is a drop-in socket replacement to Maxim's MAX485
Features
n n n n n n n n n n n Meet ANSI standard RS-485-A and RS-422-B Data rate 2.5 Mbps Single supply voltage operation, 5V Thermal shutdown protection Short circuit protection Low power BiCMOS Allows up to 32 transceivers on the bus Open circuit fail-safe for receiver Extended operating temperature range -40°C to 85°C Drop-in replacement to MAX485 Available in 8-pin SOIC and 8-Pin DIP package
Applications
n n n n n n n n Low power RS-485 systems Network hubs, bridges, and routers Point of sales equipment (ATM, barcode scanners,...) Local area networks (LAN) Integrated service digital network (ISDN) Industrial programmable logic controllers High speed parallel and serial applications Multipoint applications with noisy environment
Typical Application
20062601
A Typical multipoint application is shown in the above figure. Terminating resistors, RT, are typically required but only located at the two ends of the cable. Pull up and pull down resistors maybe required at the end of the bus to provide failsafe biasing. The biasing resistors provide a bias to the cable when all drivers are in TRI-STATE, See National Application Note, AN-847 for further information.
© 2003 National Semiconductor Corporation
DS200626
www.national.com
LMS485
Connection Diagram
8-Pin SOIC / DIP
20062602
Top View
Truth Table
DRIVER SECTION RE X X X RECEIVER SECTION RE L L H L
Note: * = Non Terminated, Open Input only X = Irrelevant Z = TRI-STATE H = High level L = Low level
DE H H L DE L L X L
DI H L X A-B +0.2V -0.2V X OPEN *
A H L Z
B L H Z RO H L Z H
Pin Descriptions
Pin # I/O 1 2 3 4 5 6 7 8 O I I I N/A I/O I/O N/A Name RO RE DE DI GND A B VCC Function Receiver Output: If A > B by 200 mV, RO will be high; If A < B by 200mV, RO will be low. RO will be high also if the inputs (A and B) are open (non-terminated) Receiver Output Enable: RO is enabled when RE is low; RO is in TRI-STATE when RE is high Driver Output Enable: The driver outputs (A and B) are enabled when DE is high; they are in TRI-STATE when DE is low. Pins A and B also function as the receiver input pins (see below) Driver Input: A low on DI forces A low and B high while a high on DI forces A high and B low when the driver is enabled Ground Non-inverting Driver Output and Receiver Input pin. Driver Output levels conform to RS-485 signaling levels Inverting Driver Output and Receiver Input pin. Driver Output levels conform to RS-485 signaling levels Power Supply: 4.75V VCC 5.25V
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LMS485
Ordering Information
Package Part Number LMS485CM 8-Pin SOIC LMS485CMX LMS485IM LMS485IMX 8-Pin DIP LMS485CNA LMS485INA Package Marking LMS485CM LMS485IM LMS485CNA LMS485INA Transport Media 95 Units/Rail 2.5k Units Tape and Reel 95 Units/Rail 2.5k Units Tape and Reel 40 Units/Rail 40 Units/Rail N08E M08A NSC Drawing
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