LTC1688IS#PBF

Drivers, Receivers, Transceivers Overview

The LTC1688IS#PBF is a high-speed RS-485 quad differential line driver manufactured by Analog Devices Inc. It supports data rates up to 100Mbps and operates on a single 3V or 5V supply. The device features guaranteed propagation delay of 8ns ±4ns over the full operating temperature range (-40°C to +85°C) and typical channel-to-channel skew of 500ps. It includes hot swap capability, maintaining high impedance outputs during power-off or three-state conditions. Electrical specifications include a short-circuit protection current of 3mA typical and a supply current of 9mA. The component is housed in a 16-lead plastic SO (SOIC) package.

Drivers, Receivers, Transceivers Feature Summary

• Hot Swap capable with high impedance outputs maintained during board insertion, removal, or power-off states
• Ultrahigh speed operation supporting data rates up to 100Mbps with narrow propagation delay variation
• Integrated thermal shutdown and voltage sensing short-circuit protection limiting output current to 3mA typical

Drivers, Receivers, Transceivers Applications

• High-speed backplane drivers for point-to-point and multipoint configurations
• STS-1/OC-1 data transmission systems
• SCSI drivers requiring high-speed differential signaling
• Complementary clock drivers for precision timing applications

Drivers, Receivers, Transceivers Procurement Notes

Verify the specific suffix 'IS' confirms the industrial temperature range of -40°C to +85°C and the '#PBF' designation indicates lead-free RoHS compliance. Confirm the package type matches the 16-lead plastic small outline (SOIC). Ensure the ordering information aligns with the manufacturer's current datasheet revision to avoid discrepancies in pinout or electrical characteristics.

Drivers, Receivers, Transceivers Selection Notes

Select the LTC1688 variant when all four drivers must be enabled simultaneously. Choose the LTC1689 if the application requires enabling only two drivers at a time. Ensure the system design accommodates the recommended 100Ω characteristic impedance for PC traces or twisted-pair cables to maintain signal integrity at maximum data rates.

Drivers, Receivers, Transceivers Part Context

This component belongs to the LTC1688/LTC1689 family of ultrahigh-speed RS-485 drivers. It is designed to replace older generation drivers like the LTC486/LTC487 while offering significantly higher data rates and improved propagation delay consistency. The device is pin-compatible with the LTC486 and LTC487 series, facilitating direct upgrades in existing designs.

Drivers, Receivers, Transceivers Replacement Considerations

LTC1688CS#PBF

Drivers, Receivers, Transceivers FAQ

How does the LTC1688 handle hot swapping?

The driver outputs maintain a high impedance state across the entire common mode range (-7V to 12V) even when the device is powered off. This prevents differential signals from being induced on the transmission line during board insertion or removal.

What is the difference between the LTC1688 and LTC1689?

The LTC1688 allows all four drivers to be enabled together via EN and ENB pins. The LTC1689 allows only two drivers to be enabled at a time, using EN12 to enable Drivers 1 and 2, and EN34 to enable Drivers 3 and 4.

What is the typical short-circuit current?

The device employs voltage sensing short-circuit protection that reduces the output current to approximately 3mA typical during a fault condition, protecting the part from excessive power dissipation.