LTC491IS#PBF

Drivers, Receivers, Transceivers Overview

The LTC491IS#PBF is a low-power differential bus transceiver designed for RS485 and RS422 applications. It operates on a single 5V supply with a typical supply current of 300mA. The device features an extended common mode range from –7V to 12V, allowing up to 32 transceivers on the bus. Key electrical parameters include a typical driver propagation delay of 28ns with 5ns skew at 2.5MB operation, 70mV typical input hysteresis, and thermal shutdown protection. It is available in a 14-lead SOIC package.

Drivers, Receivers, Transceivers Feature Summary

• Thermal shutdown circuit prevents excessive power dissipation by forcing driver outputs into a high impedance state during faults.
• Receiver includes a fail-safe feature that guarantees a high output state when inputs are left open.
• Driver maintains high impedance in three-state or power-off conditions across the entire common mode range.

Drivers, Receivers, Transceivers Applications

• Multipoint data transmission systems adhering to RS485 standards
• Full-duplex communication networks utilizing RS422 protocols
• Level translation between different logic voltage domains

Drivers, Receivers, Transceivers Procurement Notes

Verify the specific suffix #PBF indicates lead-free compliance and RoHS status. Confirm the IS designation corresponds to the industrial temperature range of -40°C to +85°C. Ensure the 14-lead SOIC package matches the target PCB footprint requirements before finalizing procurement orders.

Drivers, Receivers, Transceivers Selection Notes

Select this component for designs requiring extended common mode voltage tolerance beyond standard RS485 limits. Consider the 300mA supply current for power budget calculations. Verify compatibility with existing SN75180 pinouts if migrating legacy bipolar designs to this CMOS architecture.

Drivers, Receivers, Transceivers Part Context

This part belongs to the Linear Technology (now Analog Devices) family of low-power RS485/RS422 transceivers. It serves as a CMOS alternative to older bipolar counterparts, offering reduced power consumption while maintaining ruggedness against overload and ESD damage within the specified operating temperature range.

Drivers, Receivers, Transceivers Replacement Considerations

The datasheet lists the SN75180 as a pin-compatible predecessor. Other related parts include the LTC1686/LTC1687 for higher speed requirements and the LT1791/LTC1791A for applications needing -60V protection.