LTC1321 - RS232/EIA562/RS485 Transceivers


  • LTC1321: 2-EIA562/RS232 Transceivers/2-RS485 Transceivers
  • LTC1322: 4-EIA562/RS232 Transceivers/2-RS485 Transceivers
  • LTC1335: 4-EIA562 Transceivers/2-RS485 Transceivers with OE
  • LTC1321/LTC1322 Have the Same Pinout as SP301/SP302
  • LTC1335 Features Receiver Three-State Outputs
  • Low Supply Current: 1mA Typical
  • 15µA Supply Current in Shutdown
  • 120kBaud in EIA/TIA-562 or RS232 Mode
  • 10MBaud in RS485/RS422 Mode
  • Self-Testing Capability in Loopback Mode
  • Power-Up/Down Glitch-Free Outputs
  • Driver Maintains High Impedance in Three-State, Shutdown or With Power Off
  • Thermal Shutdown Protection
  • I/O Lines Can Withstand ±25V
  • Withstands Repeated 10kV ESD Pulses

Typical Application

LTC1321 Typical Application


The LTC1321/LTC1322/LTC1335 are low power CMOS bidirectional transceivers, each featuring two reconfigurable interface ports. Each can be configured as two RS485 differential ports, as two single-ended ports, or as one RS485 differential port and one single-ended port. The LTC1321/LTC1322 can provide RS232 or EIA562 compatible single-ended outputs; the LTC1335 provides EIA562 compatible outputs and additionally includes an output enable pin, allowing the receiver logic level outputs to be three-stated.

The RS232/EIA562 transceivers operate to 120kbaud and are in full compliance with EIA/TIA-562 specification. The RS485 transceivers operate to 10Mbaud and are in full compliance with RS485 and RS422 specifications. All interface drivers feature short-circuit and thermal shutdown protection. An enable pin allows RS485 driver outputs to be forced into high impedance which is maintained even when the outputs are forced beyond supply rails or power is off. Both driver outputs and receiver inputs feature ±10kV ESD protection. A loopback mode connects the driver outputs back to the receiver inputs for diagnostic self-test.

The LTC1321/LTC1322 can support RS232 voltage levels when 6.5V </= VDD </= 10V and –6.5V VEE >/= –10V. The LTC1335 supports receiver output enable but not RS232 levels. A shutdown mode reduces the IMCC supply current to 15µA.


CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
LTC1321CN#PBF N-24 N C 05-08-1510 (N24) Yes
LTC1321CSW#PBF SW-24 SW C 05-08-1620 (SW24) Yes
LTC1321CSW#TRPBF SW-24 SW C 05-08-1620 (SW24) Yes
LTC1321IN#PBF N-24 N I 05-08-1510 (N24) Yes
LTC1321ISW#PBF SW-24 SW I 05-08-1620 (SW24) Yes
LTC1321ISW#TRPBF SW-24 SW I 05-08-1620 (SW24) Yes

LTC1321 Package Drawing
LTC1321 Package Drawing
LTC1321 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
LTC1321CN#PBF N-24 C $5.85 $4.60 Yes
LTC1321CSW#PBF SW-24 C $5.85 $4.60 Yes
LTC1321CSW#TRPBF SW-24 C $4.70 Yes
LTC1321IN#PBF N-24 I $7.00 $5.55 Yes
LTC1321ISW#PBF SW-24 I $7.00 $5.55 Yes
LTC1321ISW#TRPBF SW-24 I $5.65 Yes
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* The USA 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 Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Click here to view our complete list of demo boards


  • Low Power RS485/RS422/EIA562/RS232 Interface
  • Cable Repeater
  • Level Translator

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