UNISONIC TECHNOLOGIES CO., LTD

UTRS458

Preliminary

CMOS IC

www.unisonic.com.tw

1 of 8

Copyright © 2016 Unisonic Technologies Co., Ltd

QW-R113-016.b

POLARITY FREE, FAIL-SAFE,

500KBPS, RS-485 / RS-422

TRANSCEIVERS WITH ±12KV

ESD-PROTECTED



DESCRIPTION

The UTC UTRS458 is a Polarity-Free half-duplex transceiver

designed for RS-485 data bus network, which contains one transmitter

and one receiver. The UTC UTRS458 features a fail-safe receiver,

which guarantees the receiver to output high when the receiver inputs

are open, short or idle.

The UTC UTRS458 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 detection function is real-time monitored the bus

polarity without any data flow on the RS485 bus.

The UTC UTRS458 also features a hot-swap glitch free protection

circuits which guarantee outputs of both the transmitter and the

receiver in a high impedance state during the power up period. So that

the large short current from power to ground will be disable by glitch

free function, which will save the power and enhance the efficiency of

the power up.

The UTC UTRS458 is optimized for signal rates up to 500Kbps

with differential voltage of 2.3V. The UTC UTRS458 also has the

thermal shutdown function when the temperature is over 150°C and

the protection of the current limitation in the transmitter to protect the

itself from the damage by the system-fault conditions during normal

operation.



FEATURES

* Meet the requirements of the EIA/TIA-485 standards.

* 5.0V single power supply.

* 1µA low-current shutdown mode.

* HBM ±12kV ESD protection.

* True fail-safe receiver while maintaining EIA/TIA-485

compatibility.

* Hot-swap glitch free protection on control inputs.

* Up to 256 transceivers on the bus.

* Maximum baud rate up to 500Kbps.

* Transmitter short circuit current limit.

* Thermal shutdown for overload protection.

* Polarity-Free for RS485 bus pins.



ORDERING INFORMATION

Ordering Number

Package

Packing

UTRS458G-S08-R

SOP-8

Tape Reel