DS481TM/NOPB

Overview

The DS481TM/NOPB is a low-power RS-485/RS-422 multipoint transceiver manufactured by Texas Instruments. It features one driver and one receiver operating from a single +5V supply, supporting data rates up to 2.0 Mbps. The device operates within an industrial temperature range of -40°C to +85°C and draws 200 μA typical quiescent current. An automatic sleep mode reduces supply current to 0.2 μA when DE is LOW and RE is HIGH for over 600 ns. It supports up to 64 transceivers on the bus due to its half-unit load input characteristic.

Feature Summary

• Automatic sleep mode activated by inactivity on enable pins to minimize power consumption
• Half-unit load receiver input capability allowing up to 64 nodes on a single bus
• Failsafe receiver feature ensuring logic-high output during open-circuit conditions
• Driver protection against short circuits and excessive power dissipation via thermal shutdown

Applications

• Multipoint RS-485 communication networks requiring extended node counts
• Industrial control systems with strict power budget constraints
• Noisy environments utilizing balanced transmission lines for bidirectional data transfer

Procurement Notes

Verify the LIFEBUY status before finalizing designs, as production is discontinued. Confirm package integrity upon receipt, as ESD protection is limited. Ensure compatibility with existing system voltage levels and interface requirements. Review the latest datasheet revision for any updates to electrical characteristics or pin configurations prior to implementation.

Selection Notes

Select this component for applications requiring high node density without repeaters. Verify that the system can tolerate the wake-up delay associated with exiting sleep mode. Ensure the design accommodates the specific enable pin logic states required to trigger the automatic sleep function effectively.

Part Context

This part belongs to the DS481 series of low-power transceivers. It is functionally compatible with the MAX481C and MAX481E devices. The NOPB suffix indicates compliance with RoHS standards and absence of antimony trioxide flame retardants.

Replacement Considerations

Direct functional substitutes include the MAX481C and MAX481E. Verify pinout compatibility and electrical specifications match the original design requirements before substitution.

FAQ

How is the automatic sleep mode triggered?

Sleep mode activates when the Driver Enable (DE) pin is held LOW and the Receiver Enable (RE) pin is held HIGH for more than 600 nanoseconds.

What is the maximum number of transceivers supported on the bus?

The DS481TM/NOPB supports up to 64 transceivers on the bus because it utilizes a half-unit load receiver input characteristic.

Does the device have failsafe protection?

Yes, the receiver includes a failsafe feature that guarantees a logic-high output if the differential input voltage is zero or the input is open circuit.