Receiver Enable Input Voltage...................... –0.3V to 6V
Driver Enable Input Voltage.......................... –0.3V to 6V
Driver Input Voltage ................................... –0.3V to 18V
Receiver Input Voltage ................................ –60V to 60V
Driver Output Voltage.................................. –60V to 60V
Receiver Output Voltage...................–0.3V to (V
CC
+ 6V)
Operating Temperature Range
LT1785C/LT1791C/
LT1785AC/LT1791AC.................................... 0°C to 70°C
LT1785I/LT1791I/
LT1785AI/LT1791AI .................................. –40°C to 85°C
LT1785H/LT1791H/
LT1785AH/LT1791AH ............................. –40°C to 125°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
PIN CONFIGURATION
TOP VIEW
TOP VIEW
RO 1
RE
2
DE 3
DI 4
N8 PACKAGE
8-LEAD PDIP
D
R
8
7
6
5
V
CC
B
A
GND
NC 1
RO 2
RE
3
DE 4
DI 5
GND 6
S8 PACKAGE
8-LEAD PLASTIC SO
GND 7
N PACKAGE
14-LEAD PDIP
D
R
14 V
CC
13 NC
12 A
11 B
10 Z
9
8
Y
NC
T
JMAX
= 150°C,
θ
JA
= 130°C/W (N8)
T
JMAX
= 150°C,
θ
JA
= 150°C/W (S8)
S PACKAGE
14-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 130°C/W (N)
T
JMAX
= 150°C,
θ
JA
= 150°C/W (S)
ORDER INFORMATION
LEAD FREE FINISH
LT1785CN8#PBF
LT1785CS8#PBF
LT1785IN8#PBF
LT1785IS8#PBF
LT1785ACN8#PBF
LT1785ACS8#PBF
LT1785AIN8#PBF
LT1785AIS8#PBF
LT1785HN8#PBF
LT1785HS8#PBF
LT1785AHN8#PBF
LT1785AHS8#PBF
LT1791CN#PBF
LT1791CS#PBF
TAPE AND REEL
LT1785CN8#TRPBF
LT1785CS8#TRPBF
LT1785IN8#TRPBF
LT1785IS8#TRPBF
LT1785ACN8#TRPBF
LT1785ACS8#TRPBF
LT1785AIN8#TRPBF
LT1785AIS8#TRPBF
LT1785HN8#TRPBF
LT1785HS8#TRPBF
LT1785AHN8#TRPBF
LT1785AHS8#TRPBF
LT1791CN#TRPBF
LT1791CS#TRPBF
PART MARKING*
1785
1785
1785I
1785I
1785A
1785A
1785AI
1785AI
1785H
1785H
1785AH
1785AH
1791
1791
PACKAGE DESCRIPTION
8-Lead PDIP
8-Lead Plastic SO
8-Lead PDIP
8-Lead Plastic SO
8-Lead PDIP
8-Lead Plastic SO
8-Lead PDIP
8-Lead Plastic SO
8-Lead PDIP
8-Lead Plastic SO
8-Lead PDIP
8-Lead Plastic SO
14-Lead PDIP
14-Lead Plastic SO
TEMPERATURE RANGE
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
0°C to 70°C
0°C to 70°C
178591fc
2
LT1785/LT1785A/
LT1791/LT1791A
ORDER INFORMATION
LEAD FREE FINISH
LT1791IN#PBF
LT1791IS#PBF
LT1791ACN#PBF
LT1791ACS#PBF
LT1791AIN#PBF
LT1791AIS#PBF
LT1791HN#PBF
LT1791HS#PBF
LT1791AHN#PBF
LT1791AHS#PBF
LEAD BASED FINISH
LT1785CN8
LT1785CS8
LT1785IN8
LT1785IS8
LT1785ACN8
LT1785ACS8
LT1785AIN8
LT1785AIS8
LT1785HN8
LT1785HS8
LT1785AHN8
LT1785AHS8
LT1791CN
LT1791CS
LT1791IN
LT1791IS
LT1791ACN
LT1791ACS
LT1791AIN
LT1791AIS
LT1791HN
LT1791HS
LT1791AHN
LT1791AHS
TAPE AND REEL
LT1791IN#TRPBF
LT1791IS#TRPBF
LT1791ACN#TRPBF
LT1791ACS#TRPBF
LT1791AIN#TRPBF
LT1791AIS#TRPBF
LT1791HN#TRPBF
LT1791HS#TRPBF
LT1791AHN#TRPBF
LT1791AHS#TRPBF
TAPE AND REEL
LT1785CN8#TR
LT1785CS8#TR
LT1785IN8#TR
LT1785IS8#TR
LT1785ACN8#TR
LT1785ACS8#TR
LT1785AIN8#TR
LT1785AIS8#TR
LT1785HN8#TR
LT1785HS8#TR
LT1785AHN8#TR
LT1785AHS8#TR
LT1791CN#TR
LT1791CS#TR
LT1791IN#TR
LT1791IS#TR
LT1791ACN#TR
LT1791ACS#TR
LT1791AIN#TR
LT1791AIS#TR
LT1791HN#TR
LT1791HS#TR
LT1791AHN#TR
LT1791AHS#TR
PART MARKING*
1791I
1791I
1791A
1791A
1791AI
1791AI
1791H
1791H
1791AH
1791AH
PART MARKING*
1785
1785
1785I
1785I
1785A
1785A
1785AI
1785AI
1785H
1785H
1785AH
1785AH
1791
1791
1791I
1791I
1791A
1791A
1791AI
1791AI
1791H
1791H
1791AH
1791AH
PACKAGE DESCRIPTION
14-Lead PDIP
14-Lead Plastic SO
14-Lead PDIP
14-Lead Plastic SO
14-Lead PDIP
14-Lead Plastic SO
14-Lead PDIP
14-Lead Plastic SO
14-Lead PDIP
14-Lead Plastic SO
PACKAGE DESCRIPTION
8-Lead PDIP
8-Lead Plastic SO
8-Lead PDIP
8-Lead Plastic SO
8-Lead PDIP
8-Lead Plastic SO
8-Lead PDIP
8-Lead Plastic SO
8-Lead PDIP
8-Lead Plastic SO
8-Lead PDIP
8-Lead Plastic SO
14-Lead PDIP
14-Lead Plastic SO
14-Lead PDIP
14-Lead Plastic SO
14-Lead PDIP
14-Lead Plastic SO
14-Lead PDIP
14-Lead Plastic SO
14-Lead PDIP
14-Lead Plastic SO
14-Lead PDIP
14-Lead Plastic SO
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
TEMPERATURE RANGE
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
This product is only offered in trays. For more information go to:
http://www.linear.com/packaging/
178591fc
3
LT1785/LT1785A/
LT1791/LT1791A
DC ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
V
OD1
V
OD2
Differential Driver Output Voltage (Unloaded)
Differential Driver Output Voltage (With Load)
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
CC
= 5V.
CONDITIONS
I
O
= 0
R = 50Ω (RS422), Figure 1
R = 27Ω (RS485), Figure 1
R = 18Ω
R = 27Ω or R = 50Ω, Figure 1
R = 27Ω or R = 50Ω, Figure 1
R = 27Ω or R = 50Ω, Figure 1
DI, DE,
RE
DI, DE,
RE
DI, DE,
RE
V
IN
= 12V
V
IN
= –7V
–60V ≤ V
IN
≤ 60V
LT1785/LT1791: –7V ≤ V
CM
≤ 12V
LT1785A/LT1791A: –7V ≤ V
CM
≤ 12V
–7V < V
CM
< 12V
I
O
= –400μA, V
ID
= 200mV
I
O
= 1.6mA, V
ID
= –200mV
RE
> 2V or Power Off
–7V ≤ V
CM
≤ 12V
– 60V ≤ V
CM
≤ 60V
–7V ≤ V
CM
≤ 12V
V
OUT
= HIGH, Force V
O
= –7V
V
OUT
= LOW, Force V
O
= 12V
V
O
= 60V
V
O
= –60V
0V ≤ V
O
≤ V
CC
–7V ≤ V
O
≤ 12V
–60V ≤ V
O
≤ 60V
No Load,
RE
= 0V, DE = 5V
No Load,
RE
= 5V, DE = 5V
No Load,
RE
= 0V, DE = 0V
No Load,
RE
= 5V, DE = 0V
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
MIN
2.0
1.5
1.2
TYP
4.1
2.70
2.45
2.2
MAX
5
UNITS
V
V
V
V
V
OD
V
OC
Δ|V
OC
|
V
IH
V
IL
I
IN1
I
IN2
Change in Magnitude of Driver Differential Output
Voltage for Complementary Output States
Driver Common Mode Output Voltage
Change in Magnitude of Driver Common Mode Output
Voltage for Complementary Output States
Input High Voltage
Input Low Voltage
Input Current
Input Current (A, B); (LT1791 or LT1785 with DE = 0V)
0.2
2
2.5
3
0.2
2
0.8
5
–0.15
–6
–0.2
–0.2
20
3.5
–1
85
50
35
35
–6
±35
–0.2
–6
5.5
5.5
4.5
0.2
0.3
6
9
9
8
0.3
125
125
90
0.25
250
250
6
4
0.3
0.5
1
0.15
–0.08
0.3
6
0.2
0
V
V
V
V
V
μA
mA
mA
mA
V
V
mV
V
V
μA
kΩ
kΩ
kΩ
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
V
TH
ΔV
TH
V
OH
V
OL
Differential Input Threshold Voltage for Receiver
Receiver Input Hysteresis
Receiver Output High Voltage
Receiver Output Low Voltage
Three-State (High Impedance) Output Current at
Receiver 0V < V
OUT
< 6V
R
IN
Receiver Input Resistance (LT1791)
LT1785
RS485 Unit Load
I
SC
Driver Short-Circuit Current
Driver Output Fault Current
Receiver Short-Circuit Current
Driver Three-State Output Current
I
CC
Supply Current
178591fc
4
LT1785/LT1785A/
LT1791/LT1791A
SWITCHING CHARACTERISTICS
SYMBOL
t
PLH
t
PHL
t
SKEW
t
r
, t
f
t
ZH
t
ZL
t
LZ
t
HZ
t
PLH
t
PHL
t
SKD
t
ZL
t
ZH
t
LZ
t
HZ
f
MAX
t
SHDN
t
ZH(SHDN)
t
ZL(SHDN)
t
ZH(SHDN)
t
ZL(SHDN)
PARAMETER
Driver Input to Output
Driver Input to Output
Driver Output to Output
Driver Rise or Fall Time
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High
Receiver Input to Output
Receiver Input to Output
Differential Receiver Skew
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable from Low
Receiver Disable from High
Maximum Data Rate
Time to Shut Down
Driver Enable from Shutdown to Output High
Driver Enable from Shutdown to Output Low
Receiver Enable from Shutdown to Output High
Receiver Enable from Shutdown to Output Low
Figures 2, 6, 8
Figures 2, 6;
RE
= 5V
Figures 2, 6;
RE
= 5V
Figures 2, 8; DE = 0V
Figures 2, 8; DE = 0V
Figures 2, 8
Figures 2, 8
Figures 2, 8
Figures 2, 8
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C, V
CC
= 5V.
CONDITIONS
Figures 3, 5
Figures 3, 5
Figures 3, 5
Figures 3, 5
Figures 4, 6
Figures 4, 6
Figures 4, 6
Figures 4, 6
Figures 3, 7
Figures 3, 7
l
l
l
l
l
l
l
l
l
MIN
TYP
700
700
100
MAX
2000
2000
2000
3000
3000
5000
5000
900
900
1000
1000
1000
1000
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
kbps
μs
μs
μs
μs
μs
200
800
500
800
200
800
400
400
200
300
300
400
400
250
3
12
12
4
4
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
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