LT1785 Linear Technology, LT1785 Datasheet - Page 12

• Manufacturer Part Number: LT1785
• Description: 60V Fault Protected RS485/RS422 Transceivers
• Manufacturer: Linear Technology

RELATED PARTS
LT1785/LT1785A
LT1791/LT1791A
TYPICAL APPLICATIONS
PART NUMBER
LTC485
LTC491
LTC1483
LTC1485
LTC1487
LTC1520
LTC1535
LTC1685
LTC1687
12
RO
RE
DE
DI
2
3
1
4
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] FAX: [phone] www.linear-tech.com
TX
LT1785
RX
DESCRIPTION
Low Power RS485 Interface Transceiver
Differential Driver and Receiver Pair
Ultralow Power RS485 Low EMI Transceiver
Differential Bus Transceiver
Ultralow Power RS485 with Low EMI, Shutdown and High Input Impedance
50Mbps Precision Quad Line Receiver
Isolated RS485 Full-Duplex Transceiver
52Mbps RS485 Half-Duplex Transceiver
52Mbps RS485 Full-Duplex Transceiver
RO
RE
DE
DI
B 7
A
6
2
3
1
4
120
R
TX
T
LT1785
RX
Figure 11. RS485 Network with 120V AC Line Fault Protection
U
Figure 10. Half-Duplex RS485 Network Operation
B 7
A
DI
8
6
5
4
V
LT1785
CC
DE
3
1.5KE36CA
6
A
RE
2
B
7
RO
1
POLYSWITCH
TR600-150
RAYCHEM
2
COMPOSITE
DI
CARBON
4
47
47
5W
LT1785
DE
3
6
A
RE
0.1 F
300V
2
B
7
RO
R
1
T
,120
COMMENTS
I
I
Controlled Driver Slew Rate
10Mbaud Operation
Up to 256 Transceivers on the Bus
Channel-to-Channel Skew 400ps (Typ)
2500V
Propagation Delay Skew 500ps (Typ)
Propagation Delay Skew 500ps (Typ)
CC
CC
= 300 A (Typ)
= 300 A
RMS
Isolation in Surface Mount Package
120
R
178591f LT/TP 0300 4K • PRINTED IN THE USA
T
LINEAR TECHNOLOGY CORPORATION 1998
7
6
1785/91 F11
B
A
LT1785
RX
TX
2
3
1
4
1785/91 F10
RO
RE
DE
DI