DatasheetsPDF.com

LMS1485 Dataheets PDF



Part Number LMS1485
Manufacturers National Semiconductor
Logo National Semiconductor
Description 5V Low Power RS-485 Differential Bus Transceiver
Datasheet LMS1485 DatasheetLMS1485 Datasheet (PDF)

LMS1485 5V Low Power RS-485 Differential Bus Transceiver July 2003 LMS1485 5V Low Power RS-485 Differential Bus Transceiver General Description The LMS1485 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 LMS1485 combines a TRI-STATE™ differential line.

  LMS1485   LMS1485



Document
LMS1485 5V Low Power RS-485 Differential Bus Transceiver July 2003 LMS1485 5V Low Power RS-485 Differential Bus Transceiver General Description The LMS1485 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 LMS1485 combines a TRI-STATE™ 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 LMS1485 is build with National’s advanced BiCMOS process and is available in a 8-Pin SOIC package. It is a drop-in socket replacement to ADI’s ADM1485 and LTC’s LT1485. Features n n n n n n n n n n n n n n n Meet ANSI standard RS-485-A and RS-422-B Data rate 30Mbps Single supply voltage operation, 5V Wide input and output voltage range Thermal shutdown protection Short circuit protection Driver propagation delay 10ns Receiver propagation delay 25ns High impedance outputs with power off Open circuit fail-safe for receiver Extended operating temperature range −40˚C to 85˚C ESD rating 8kV HBM Drop-in replacement to ADM1485 and LT1485 Available in 8-pin SOIC Low supply current, ICC = 1mA 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 20048801 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 DS200488 www.national.com LMS1485 Connection Diagram 8-Pin SOIC 20048802 Top View Ordering Information Package Part Number LMS1485M 8-Pin SOIC LMS1485MX LMS1485IM LMS1485IMX Package Marking LMS1485M LMS1485IM Transport Media 95 Units/Rail 2.5k Units Tape and Reel 95 Units/Rail 2.5k Units Tape and Reel M08A NSC Drawing 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 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 www.national.com 2 LMS1485 Absolute Maximum Ratings (Note 1) ESD Rating (Note 4) (Note 9) Soldering Information Infrared or Convection (20 sec.) 2kV 235˚C If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage, VCC (Note 2) Input Voltage, VIN (DI, DE, or RE) Voltage Range at Any Bus Terminal (AB) Receiver Outputs Package Thermal Impedance, θJA SOIC (Note 3) Junction Temperature (Note 3) Operating Free-Air Temperature Range, TA Commercial Industrial Storage Temperature Range ESD Rating (Note 4) (Note 8) 0˚C to 70˚C −40˚C to 85˚C −65˚C to 150˚C 8kV 125˚C/W 150˚C 7V −0.3V to VCC+ 0.3V −7V to 12V −0.3V to VCC + 0.3V Operating Ratings Min Nom Max Supply Voltage, VCC Voltage at any Bus Terminal (Separately or Common Mode) VIN or VIC High-Leve.


LMS12JC40 LMS1485 LMS1487


@ 2014 :: Datasheetspdf.com :: Semiconductors datasheet search & download site.
(Privacy Policy & Contact)