DS36C280TM

Overview

The DS36C280 is a low-power CMOS RS-485 transceiver designed for multipoint data transmission. It operates at a supply voltage of +4.75V to +5.25V with a maximum quiescent current of 500 μA. The device supports an adjustable slew rate control via an external resistor on Pin 2, allowing edge rates from approximately 100 ns (shorted) to 3 μs (open). It features a wide common-mode range of −7V to +12V and includes thermal shutdown circuitry. The standard DS36C280 offers a ¼ unit load input impedance, supporting up to 128 nodes, while the DS36C280T variant provides a ½ unit load for up to 64 nodes.

Feature Summary

• Adjustable Slew Rate Control: Allows user-defined driver rise and fall times using an external resistor to minimize electromagnetic interference (EMI).
• High Node Capacity: Offers selectable input loading options (¼ or ½ unit load) to support bus networks of up to 128 nodes.
• Glitch-Free Operation: Built-in power-up/down glitch-free circuitry permits live insertion and displacement without system disruption.

Applications

• Multipoint industrial communication buses requiring high node density.
• Battery-powered systems prioritizing low standby power consumption.
• Applications sensitive to electromagnetic interference (EMI) requiring controlled signal edge rates.

Procurement Notes

Verify component authenticity through authorized Texas Instruments distributors or certified partners. Request official datasheets and material declarations to confirm compliance with RoHS standards and specific package markings. Ensure storage conditions account for moisture sensitivity levels prior to soldering.

Selection Notes

Select the DS36C280TM for industrial temperature ranges (-40°C to +85°C) and the DS36C280M for commercial ranges (0°C to +70°C). Choose the TM suffix for the ½ unit load configuration (up to 64 nodes) and the M suffix for the ¼ unit load configuration (up to 128 nodes). Confirm that the required data rate accommodates the selected slew rate setting.

Part Context

The DS36C280 belongs to the DS36C2xx series of low-power RS-485 transceivers from Texas Instruments. It shares architectural similarities with the DS36C278 and DS36C279 but distinguishes itself by offering adjustable slew rate control rather than automatic sleep mode functionality.

Replacement Considerations

Publicly confirmed direct substitutes include the DS36C278 and DS36C279. Note that these alternatives lack the adjustable slew rate feature found in the DS36C280. Verify pin compatibility and functional differences before implementation.

FAQ

How does the slew rate control affect the maximum data rate?

Slowing the driver edge rates by increasing the resistance on the SR pin reduces the maximum achievable data rate. Users must balance EMI reduction requirements against bandwidth needs.

What is the difference between the DS36C280 and DS36C280T?

The primary difference is the receiver input impedance. The DS36C280 has a ¼ unit load, supporting up to 128 nodes, while the DS36C280T has a ½ unit load, supporting up to 64 nodes.

Does the device support live insertion?

Yes, the DS36C280 includes built-in power-up/down glitch-free circuitry, which allows for safe live insertion and displacement of the transceiver onto the bus.