DS36C279TMX

Overview

The DS36C279TMX/NOPB is a low-power RS-485 transceiver manufactured by Texas Instruments. It operates at a single +5V supply with a maximum active current of 500 μA and reduces to 10 μA in automatic sleep mode. The device supports data rates up to 10 Mb/s and features a wide common-mode range from -7V to +12V. It provides ¼ unit load capability, supporting up to 128 nodes on the bus. The component includes thermal shutdown protection, fail-safe receiver circuitry, and glitch-free power-up/down logic. It is housed in an 8-pin SOIC package.

Feature Summary

• Automatic sensing sleep mode that activates when both driver and receiver are disabled, significantly reducing power consumption for extended idle periods.
• Built-in thermal shutdown circuitry that forces outputs to a high impedance state to prevent damage during excessive power dissipation or fault conditions.
• Fail-safe receiver design ensures a high output state when differential inputs are left open or disconnected.
• Glitch-free power-up/down circuitry allows safe live intersection and displacement without signal corruption.

Applications

• Multipoint data transmission systems requiring compliance with RS-485 standards.
• Power-conscious industrial applications where devices remain inactive for long durations.
• Bus interfaces supporting high node counts (up to 128) utilizing quarter unit load specifications.

Procurement Notes

Verify the specific ordering suffix against the latest Package Option Addendum to confirm availability status and environmental compliance. Confirm the package drawing designation matches the required footprint. Ensure the device marking aligns with production revisions. Cross-reference the manufacturer part number with distributor catalogs to validate current stock levels and lead times before finalizing procurement orders.

Selection Notes

Select this component for designs requiring low standby power and high node density on RS-485 networks. The ¼ unit load specification distinguishes it from standard half-load devices, allowing greater bus capacity. Verify that the operating temperature range meets the application's environmental requirements. Consider the automatic sleep mode timing constraints if rapid wake-up transitions are critical to system performance.

Part Context

This transceiver belongs to the DS36C27x family of low-power RS-485 devices. It shares architectural similarities with the DS36C278 and DS36C280 but offers unique feature sets such as automatic sleep mode functionality. The device serves as a drop-in replacement for legacy components like the LTC485, MAX485, and DS75176 in compatible designs.

Replacement Considerations

Publicly confirmed drop-in replacements include the LTC485, MAX485, and DS75176. Verify pin compatibility and electrical parameter margins when substituting these parts. Ensure the alternative device supports the required unit load configuration and temperature range for the specific application environment.

FAQ

How does the device enter sleep mode?

The device enters sleep mode automatically when both the Driver Enable (DE) pin is asserted low and the Receiver Enable (RE*) pin is asserted high for more than 600 ns.

What is the maximum number of nodes supported?

The DS36C279 features a ¼ unit load specification, allowing it to support up to 128 nodes on a single bus within the specified temperature range.

What happens during a thermal fault condition?

An onboard thermal shutdown circuit detects excessive power dissipation and forces the driver outputs into a high impedance state to protect the device from damage.