RS-485 Transceivers with Integrated 100Ω/120Ω Termination Resistors

The MAX13450E/MAX13451E are half-duplex and full-duplex RS-485 transceivers. These devices feature internal 100Ω and 120Ω termination resistors. The resistor values are pin selectable. A logic supply input allows interfacing to logic levels down to +1.8V.

The MAX13450E/MAX13451E feature strong drivers specified to drive low-impedance lines found when a fully loaded bus, based on today's 100Ω characteristic impedance cable, is doubly terminated. Both devices allow slew-rate limiting of the driver output to reduce EMI and reflections for data rates up to 500kbps.

The MAX13451E has a FAULT alarm indication output to signal to the system that an error condition exists in the driver. The MAX13451E also features a logic inversion function. The logic inversion allows phase reversal of the A-B signals in case these are inadvertently connected wrongly.

The MAX13450E/MAX13451E have 1/8-unit load receiver input impedance, allowing up to 256 transceivers on the bus. All driver outputs are protected to ±30kV ESD using the Human Body Model (HBM).

The MAX13450E/MAX13451E are available in a 14-pin TSSOP package and operate over the automotive −40°C to +125°C temperature range.

Applications

* Industrial Control Systems

* Medical Networks

* Motor Control

* Portable Industrial Equipment

* Security Networks

* Easy Configuration of RS-485 Networks Up to 20Mbps (max) Data Rate

* Software/Pin-Selectable 100Ω/120Ω Termination

* Integrated, Switchable Resistors Eliminate the Need for External Resistors or DIP Switches

* Driver Drives 100Ω Double Termination and Supports Cat-5/Cat-6 and 24-AWG Cables

* Pin-Selectable Slew-Rate Limiting Reduces EMI for Data Rates Up to 500kbps

* 1/8 Unit Load Allows Up to 256 Transceivers On the Bus

* Designed to Perform in Harsh Environments

* Extended ESD Protection

* ±30kV Human Body Model

* ±15kV Air Gap Discharge per IEC 61000-4-2

* ±7kV Contact Discharge per IEC 61000-4-2

* Inverting of A, B Line Polarity (MAX13451E) Allows Phase Reversal if Misconnected

* Thermal and Overcurrent Protection

* Driver Fault Indication (MAX13451E)

* Fail-Safe Receivers

* −40°C to +125°C Temperature Range

* +4.5V to +5.5V Supply Voltage Range

* Integrated Low-Voltage Logic Interface (Down to 1.8V) Interfaces with Small-Geometry ASICs and FPGA