特性 Features

? Polarity Free for RS485 bus pins

? Integrated TVS Protection for Bus Terminals :

±15 kV IEC 61000-4-2, Contact Discharge

±20 kV IEC 61000-4-2, Air-Gap Discharge

? HBM ±8kV ESD Protection for all pins

? MM ±800V ESD Protection for all pins

? Meet the Requirements of the EIA/TIA-485

Standards with 5V Power Supply

? True Fail-Safe Receiver While Maintaining

EIA/TIA-485 Compatibility

? Data Rate up to 10Mbps

? Hot-Swap Glitch free Protection on Control

Inputs

? Up to 256 Transceivers on the Bus

Applications

? Energy Meter Networks

? Motor Control

? Industrial Control

? Telecommunications Equipment

? Security System

? Building Automation Networks

描述 Description

The AZRS485N is a Polarity-Free half-duplex

RS485 transceiver IC with ±15kV IEC 61000-4-2

contact discharge protection. This device is fully

compliant with the EIA/TIA-485 standard with 5V

power supply. The Parity-Free AZRS485N can

automatically detect the polarity for A and B pins

when pull-high for A and “pull-low” for B have

been designed on the RS485 bus. The polarity

detection function will be enabled when the

AZRS485N has been power up to 5V.

The detection function is real-time monitored the

bus polarity without any data flow on the RS485

bus. AZRS485N is slave-type RS485 to feature

the Polarity Free function, which can not design

the pull-up and pull-down resistor on the slave

device.

AZRS485N features an advanced fail-safe

receiver, which combined the true fail-safe and

Polarity Free function to guarantees the output of

the receiver to be logic high when the differential

inputs (bus pins, A and B) of the receiver are

open, short, idle, and even inverting connection.

AZRS485N features a hot-swap glitch-free

function which guarantees outputs of both the

transmitter and the receiver in a high impedance

state so as to prevent short current event during

the power up period. AZRS485N has the thermal

shutdown and the current limited function in the

transmitter to protect the device from damage by

system fault conditions during normal operating

condition. AZRS485N is designed 1/8 unit load

with minimum 96kohm of input impedance, which

can connect 256 devices on a bus at least.