DS1487M/NOPB

Drivers, Receivers, Transceivers Overview

The DS1487M/NOPB is a low-power RS-485 multipoint transceiver manufactured by Texas Instruments. It integrates one driver and one receiver, supporting data rates up to 2.0 Mbps with a single +5V supply. The device presents a ¼ unit load to the bus, enabling connections of up to 128 nodes without repeaters. Key electrical parameters include a typical quiescent current of 200 µA, a common-mode input voltage range of −7V to +12V, and guaranteed full-load differential output voltage (VOD3) of 1.5V minimum. Driver propagation delay is typically 40 ns, while receiver propagation delay is typically 200 ns. The component operates within a temperature range of 0°C to +70°C and features TRI-STATE outputs.

Drivers, Receivers, Transceivers Feature Summary

• Supports multipoint communication on RS-485 buses with a ¼ unit load specification allowing up to 128 connected nodes.
• Includes short-circuit current limiting and thermal shutdown circuitry to protect the driver under fault conditions.
• Receiver incorporates a failsafe feature that guarantees a logic-high output state when the input lines are open.

Drivers, Receivers, Transceivers Applications

• RS-485 multipoint communication networks
• RS-422 point-to-point or multi-drop links
• Industrial control systems requiring half-duplex data transmission

Drivers, Receivers, Transceivers Procurement Notes

Verify the specific ordering suffix against the manufacturer's official documentation to confirm package type and temperature range. Confirm whether the NOPB suffix indicates lead-free compliance and RoHS status according to the latest datasheet revision. Ensure compatibility with existing system power supplies and signal levels before procurement.

Drivers, Receivers, Transceivers Selection Notes

Select this component for applications requiring low standby power consumption and high node density on the bus. Verify that the operating environment remains within the specified 0°C to +70°C temperature range. Consider the 2.0 Mbps maximum data rate limit when designing for high-speed serial communication requirements.

Drivers, Receivers, Transceivers Part Context

This component belongs to the National Semiconductor DS1487 family, which was acquired by Texas Instruments. The device serves as a standard interface solution for industrial serial communication protocols. It maintains functional compatibility with similar transceivers from other manufacturers, facilitating design reuse across different hardware platforms.

Drivers, Receivers, Transceivers Replacement Considerations

The datasheet explicitly states pin and functional compatibility with the MAX1487. Designers may consider the MAX1487 as a direct substitute if available, provided the alternative meets the same electrical specifications and package constraints.

Drivers, Receivers, Transceivers FAQ

What is the maximum number of transceivers supported on a single RS-485 bus?

The DS1487 provides a ¼ unit load to the bus, allowing up to 128 transceivers to be connected together without the use of repeaters.

How does the device handle an open receiver input?

The receiver includes a failsafe feature that guarantees a logic-high output if the input is open circuit.

What protection mechanisms are included for the driver section?

The driver features short-circuit current limiting and thermal shutdown circuitry that places the outputs into a TRI-STATE state if excessive power dissipation occurs.