1. Products
  2. Interface and Isolation
  3. RS-232 / RS-422 / RS-485 / RS-562
  4. RS-485 and RS-422
  5. LT1791


Overview

Features and Benefits

  • Protected from Overvoltage Line Faults to ±60V
  • Pin Compatible with LTC485 and LTC491
  • High Input Impedance Supports Up to 128 Nodes
  • No Damage or Latchup to ESD
    • IEC-1000-4-2 Level 4: ±15kV Air Discharge
    • IEC-1000-4-2 Level 2: ±4kV Contact Discharge
  • Controlled Slew Rates for EMI Emissions Control
  • Guaranteed High Receiver Output State for Floating, Shorted or Inactive Inputs (LT1785A/LT1791A)
  • Outputs Assume a High Impedance When Off or Powered Down
  • Drives Low Cost, Low Impedance Cables
  • Short-Circuit Protection on All Outputs
  • Thermal Shutdown Protection
  • Guaranteed Operation to 125°C
  • AEC-Q100 Qualified for Automotive Applications (LT1785#W)

Product Details

The LT1785/LT1791 are half-duplex and full-duplex differential bus transceivers for RS485 and RS422 applications which feature on-chip protection from overvoltage faults on the data transmission lines. Receiver input and driver output pins can withstand voltage faults up to ±60V with respect to ground with no damage to the device. Faults may occur while the transceiver is active, shut down or powered off.

Data rates to 250kbaud on networks of up to 128 nodes are supported. Controlled slew rates on the driver outputs control EMI emissions and improve data transmission integrity on improperly terminated lines. Drivers are specified to operate with inexpensive cables as low as 72Ω characteristic impedance.

The LT1785A/LT1791A devices have “fail-safe” receiver inputs to guarantee a receiver output high for shorted, open or inactive data lines. On-chip ESD protection eliminates need for external protection devices.

The LT1785/LT1785A are available in 8-lead DIP and SO packages and the LT1791/LT1791A in 14-lead DIP and SO packages.

Applications

  • Industrial Control Data Networks
  • CAN Bus Applications
  • HVAC Controls

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Evaluation Kits (1)

Tools & Simulations

IBIS Models

Product Recommendations

LT1791 Companion Parts

Recommended Related Parts

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.

Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
LT1791ACN#PBF Material Declaration Reliability Data 14-Lead PDIP (Narrow 0.3 Inch)
LT1791ACS#PBF Material Declaration Reliability Data 14-Lead SOIC (Narrow 0.15 Inch)
LT1791ACS#TRPBF Material Declaration Reliability Data 14-Lead SOIC (Narrow 0.15 Inch)
LT1791AHN#PBF Material Declaration Reliability Data 14-Lead PDIP (Narrow 0.3 Inch)
LT1791AHS#PBF Material Declaration Reliability Data 14-Lead SOIC (Narrow 0.15 Inch)
LT1791AHS#TRPBF Material Declaration Reliability Data 14-Lead SOIC (Narrow 0.15 Inch)
LT1791AIN#PBF Material Declaration Reliability Data 14-Lead PDIP (Narrow 0.3 Inch)
LT1791AIS#PBF Material Declaration Reliability Data 14-Lead SOIC (Narrow 0.15 Inch)
LT1791AIS#TRPBF Material Declaration Reliability Data 14-Lead SOIC (Narrow 0.15 Inch)
LT1791CN#PBF Material Declaration Reliability Data 14-Lead PDIP (Narrow 0.3 Inch)
LT1791CS#PBF Material Declaration Reliability Data 14-Lead SOIC (Narrow 0.15 Inch)
LT1791CS#TRPBF Material Declaration Reliability Data 14-Lead SOIC (Narrow 0.15 Inch)
LT1791HN#PBF Material Declaration Reliability Data 14-Lead PDIP (Narrow 0.3 Inch)
LT1791HS#PBF Material Declaration Reliability Data 14-Lead SOIC (Narrow 0.15 Inch)
LT1791HS#TRPBF Material Declaration Reliability Data 14-Lead SOIC (Narrow 0.15 Inch)
LT1791IN#PBF Material Declaration Reliability Data 14-Lead PDIP (Narrow 0.3 Inch)
LT1791IS#PBF Material Declaration Reliability Data 14-Lead SOIC (Narrow 0.15 Inch)
LT1791IS#TRPBF Material Declaration Reliability Data 14-Lead SOIC (Narrow 0.15 Inch)
Wafer Fabrication Data R001 Reliability Data

PCN-PDN Information

Select a model from the dropdown below to subscribe to PCN/PDN notifications and view past notifications as well.

Sample & Buy


Ordering FAQs


See our Ordering FAQs for answers to questions about online orders, payment options and more.

 

Buy Now Pricing


(**) Displayed Buy Now Price and Price Range is based on small quantity orders.

 

List Pricing


(*)The 1Ku list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

 

Lead Times


Please see the latest communication from our CCO regarding lead times.

 

Sampling


Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.


Price Table Help

 

Evaluation Boards

Pricing displayed is based on 1-piece.

Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.