LT1785/LT1785A/
LT1791/LT1791A
18
178591fd
For more information www.linear.com/LT1785
LINEAR TECHNOLOGY CORPORATION 1998
LT 0315 REV D • PRINTED IN USA
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear.com/LT1785
relaTeD parTs
Typical applicaTion
Figure 10. Half-Duplex RS485 Network Operation
4
3
2
1
A
B
7
6
RO
RE
DE
DI
178591 F10
RX
TX
R
T
120Ω
R
T
120Ω
LT1785
4
3
2
1
A
B
7
6
RO
RE
DE
DI
RX
TX
LT1785
4
3
2
1
A
B
7
6
RO
RE
DE
DI
4
3
2
1
A
B
7
6
RO
RE
DE
DI
LT1785
LT1785
4
3
2
1
A
B
7
8
V
CC
5
6
RO
RE
DE
DI
RX
TX
R
T
,120Ω
178591 F11
0.1µF
300V
47Ω
1.5KE36CA
47Ω
CARBON
COMPOSITE
5W
LT1785
POLYSWITCH
TR600-150
× 2
Figure 11. RS485 Network with 120V AC Line Fault Protection
PART NUMBER DESCRIPTION COMMENTS
LTC2854/LTC2855 3.3V 20Mbps RS485/RS422 Transceivers with Integrated
Switchable Termination
Up to ±25kV HBM ESD, 125°C Operation
LTC2856/LTC2857/
LTC2858
5V 20Mbps and Slew Rate Limited 15kV RS485/RS422
Transceivers
±15kV ESD, 125°C Operation
LTC2850/LTC2851/
LTC2852
3.3V 20Mbps RS485/RS422 Transceivers ±15kV ESD, 125°C Operation
LTC2859/LTC2861 20Mbps RS485 Transceivers with Integrated Switchable
Termination
Integrated, Switchable,120Ω Termination Resistor, ±15kV ESD
LTC2862/LTC2863/
LTC2864/LTC2865
±60V Fault Protected 3V to 5.5V RS485/RS422 Transceivers 20Mbps or 250kbps, ±15kV HBM ESD, ±25V Common Mode
Range
LTM2881 Complete 3.3V Isolated RS485/RS422 µModule
®
Transceiver
+ Power
2500V
RMS
Isolation with Integrated Isolated DC/DC Converter and
Switchable Termination
