|Information||Full Duplex RS-485 Transceivers|
|Supported Protocols||RS-422, RS-485|
|Supply Voltage (Nom) (V)||5|
|No. of Tx||1|
|No. of Rx||1|
|HBM ESD (kV)||2|
|IEC 61000-4-2 Contact (±kV)||-|
|Fault Tolerance (V)|
|Temperature Range (°C)||0 to 70, -40 to 85|
|Data Rate (MAX) (Mbps)||5|
|Transient Tolerance (V)|
|ICC (Max) (mA)||-|
|Typ Shutdown Current (µA)|
|PROFIBUS (5V) or High Output (3V)|
The SP490 is a low power differential line driver/receiver meeting RS-485 and RS-422 standards up to 5Mbps. The SP491 is identical to the SP490 with the addition of driver and receiver tri-state enable lines. Both products feature ±200mV receiver input sensitivity, over wide common mode range. The SP490 is available in 8-pin plastic DIP and 8-pin NSOIC packages for operation over the commercial and industrial temperature ranges. The SP491 is available in 14-pin DIP and 14-pin NSOIC packages for operation over the commercial and industrial temperature ranges.
- +5V Only
- Low Power BiCMOS
- Driver/Receiver Enable (SP491)
- RS-485 and RS-422 Drivers/Receivers
- Pin Compatible with LTC490 and SN75179
Documentation & Design Tools
|Data Sheets||SP490_SP491 Full Duplex RS-485 Transceivers||1.0.2||February 2018||647.6 KB|
|Application Notes||RS-232 and RS-485 PCB Layout Application Note||R00||December 2022||2.8 MB|
|Application Notes||AN-292, RS-485 Cable Lengths vs Data Signaling Rate||R01||July 2022||2.7 MB|
|Application Notes||AN-291, RS-485 Advanced Fail-Safe Feature||00||January 2022||920.5 KB|
|Application Notes||ANI-13, RS-485 and RS-422 Physical Topologies||D||December 2006||183.2 KB|
|Product Brochures||Interface Brochure||October 2022||3.8 MB|
Quality & RoHS
Parts & Purchasing
|Part Number||Pkg Code||Min Temp||Max Temp||Status||Suggested Replacement||Buy Now||Order Samples||PDN|
Active - the part is released for sale, standard product.
EOL (End of Life) - the part is no longer being manufactured, there may or may not be inventory still in stock.
CF (Contact Factory) - the part is still active but customers should check with the factory for availability. Longer lead-times may apply.
PRE (Pre-introduction) - the part has not been introduced or the part number is an early version available for sample only.
OBS (Obsolete) - the part is no longer being manufactured and may not be ordered.
NRND (Not Recommended for New Designs) - the part is not recommended for new designs.
FAQs & Support
Search our list of FAQs for answers to common technical questions.
For material content, environmental, quality and reliability questions review the Quality tab or visit our Quality page.
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Submit a Technical Support Question As a New Question
For RS-232 it is 50 feet (15 meters), or the cable length equal to a capacitance of 2500 pF, at a maximum transmission rate of 19.2kbps. When we reduce the baud rate, it allows for longer cable length. For Example:
Baud Rate (bps)
Maximum RS-232 Cable Length (ft)
Fail Safe is an attempt to keep the output of the RS-485 receiver to a known state. Transceivers may have standard fail safe or advanced / enhanced receiver fail safe features. Standard fail safe supports open inputs while enhanced fail safe transceivers such as the SP339 and XR34350 support open input, shorted input and undriven terminated lines without external biasing. See Application Note ANI-22 for more detail.
The Parts & Purchasing section of the product page shows the Status of all orderable part numbers for that product. Click Show obsolete parts, to see all EOL or OBS products.