LTC485

1

485fi

Typical applicaTion

DescripTion

Low Power RS485

Interface Transceiver

ceiver designed for multipoint data transmission standard

RS485 applications with extended common mode range

(12V to –7V). It also meets the requirements of RS422.

The CMOS design offers significant power savings over

its bipolar counterpart without sacrificing ruggedness

against overload of ESD damage.

The driver and receiver feature three-state outputs, with

the driver outputs maintaining high impedance over the

entire common mode range. Excessive power dissipa-

tion caused by bus contention or faults is prevented by a

thermal shutdown circuit which forces the driver outputs

into a high impedance state.

The receiver has a fail-safe feature which guarantees a

high output state when the inputs are left open.

The LTC485 is fully specified over the commercial and

extended industrial temperature range.

Driver Outputs

FeaTures

applicaTions

n

n

Designed for RS485 Interface Applications

n

Single 5V supply

n

–7V to 12V Bus Common Mode Range Permits

±7V Ground Difference Between Devices on the Bus

n

Thermal Shutdown Protection

n

Power-Up/Down Glitch-Free Driver Outputs

Permit Live Insertion or Removal of Transceiver

n

Driver Maintains High Impedance in Three-State

or with the Power Off

n

Combined Impedance of a Driver Output and

Receiver Allows Up to 32 Transceivers on the Bus

n

70mV Typical Input Hysteresis

n

30ns Typical Driver Propagation Delays

with 5ns Skew for Up to 2.5MB Operation

n

Pin Compatible with ±60V Protected LT1785 and

52Mbps LTC1685

n

Low Power RS485/RS422 Transceiver

n

Level Translator

L

, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

GND1

R

RO1

RE1

DE1

DI1

D

GND2

R

RO2

RE2

DE2

DI2

D

Rt

Rt

485 TA01a

485 TA01b

A

B