LTC1387CSW#PBF

Drivers, Receivers, Transceivers Overview

The LTC1387CSW#PBF is a low-power reconfigurable CMOS bidirectional transceiver manufactured by Analog Devices Inc. It operates from a single 5V supply and can be configured as one RS485 differential port or two RS232 single-ended ports. The device features an onboard charge pump requiring four 0.1µF capacitors to generate boosted positive and negative supplies for RS232 drivers. It supports data rates up to 5MBd in fast slew mode and 150kBd in slow slew mode. The supply current is typically 7mA, reducing to 5µA in shutdown mode. It is housed in a 20-lead plastic SO (SW) package with an operating temperature range of 0°C to 70°C.

Drivers, Receivers, Transceivers Feature Summary

• Configurable interface supporting either one RS485/RS422 differential port or two RS232/EIA562 single-ended ports via logic control.
• Integrated charge pump generates internal ±VDD and VEE rails from a single 5V supply using external 0.1µF capacitors.
• Logic-selectable fast or slow slew rate for the RS485 driver to minimize signal reflections and EMI.
• Includes loopback mode for diagnostic self-testing and separate enable controls for drivers and receivers.

Drivers, Receivers, Transceivers Applications

• Point-of-sale terminals
• Software selectable multiprotocol interface ports
• Cable repeaters
• Level translators

Drivers, Receivers, Transceivers Procurement Notes

Verify the specific suffix #PBF indicates lead-free compliance and RoHS status before procurement. Confirm the SW package variant matches the required footprint dimensions. Ensure the 0°C to 70°C commercial temperature rating aligns with the system environment. Cross-reference the manufacturer part number with authorized distributors to ensure authenticity.

Drivers, Receivers, Transceivers Selection Notes

Select this component when a single-port solution is needed to switch between RS485 and RS232 standards without additional hardware. The integrated charge pump eliminates the need for dual power supplies. Consider the thermal performance if high drive currents are expected, as thermal shutdown activates at 150°C. Verify that the 20-lead SOIC package fits the PCB layout constraints.

Drivers, Receivers, Transceivers Part Context

The LTC1387 belongs to the Analog Devices interface IC family designed for versatile communication protocols. It replaces discrete transistor solutions or multiple dedicated transceivers by combining RS232 and RS485 functionality into a single chip. This integration reduces board space and simplifies design for applications requiring flexible serial communication interfaces.

Drivers, Receivers, Transceivers Replacement Considerations

ISL81387IAZ by Renesas Electronics Corporation is a documented similar replacement option.

Drivers, Receivers, Transceivers FAQ

How does the SLEW pin affect RS485 operation?

In RS485 mode, the SLEW pin controls the driver slew rate. A high logic level selects the fast slew rate for data rates up to 5MBd, while a low logic level selects the slow slew rate to reduce reflections, supporting data rates up to 150kBd.

What is the function of the ON pin during shutdown?

The ON pin keeps the charge pump active regardless of the DXEN and RXEN states. Keeping ON high allows the drivers and receivers to be enabled immediately without waiting for the charge pump stabilization time, which is typically 100ms.

Does the device provide protection against short circuits?

Yes, all interface drivers feature short-circuit and thermal shutdown protection. The thermal shutdown circuit disables outputs when the die temperature reaches 150°C and reenables them when it cools to 135°C.