Receiver Input Voltage ............................................ ±14V
Receiver Output Voltages ............... –0.5V to V
CC
+ 0.5V
Operating Temperature Range
LTC485I ........................................ –40°C ≤ T
A
≤ 85°C
LTC485C ............................................0°C ≤ T
A
≤ 70°C
LTC485M
(OBSOLETE)
................–55°C ≤ T
A
≤ 125°C
Lead Temperature (Soldering, 10 sec)................... 300°C
Storage Temperature Range .................. –65°C to 150°C
S8 PACKAGE
8-LEAD PLASTIC SOIC
OBSOLETE PACKAGE
T
JMAX
= 125°C,
θ
JA
= 100°C/W (N)
T
JMAX
= 150°C,
θ
JA
= 150°C/W (S)
T
JMAX
= 155°C,
θ
JA
= 100°C/W (J)
J8 PACKAGE
8-LEAD CERAMIC DIP
ORDER INFORMATION
LEAD FREE FINISH
LTC485CN8#PBF
LTC485CS8#PBF
LTC485IN8#PBF
LTC485IS8#PBF
LEAD BASED FINISH
LTC485CN8
LTC485CS8
LTC485IN8
LTC485IS8
LTC485MJ8
TAPE AND REEL
NA
LTC485CS8#TRPBF
NA
LTC485IS8#TRPBF
TAPE AND REEL
NA
LTC485CS8#TR
NA
LTC485IS8#TR
NA
http://www.linear.com/product/LTC485#orderinfo
PART MARKING*
LTC485CN8
485
LTC485IN8
485I
PART MARKING*
LTC485CN8
485
LTC485IN8
485I
LTC485MJ8
PACKAGE DESCRIPTION
8-Lead Plastic DIP
8-Lead Plastic SOIC
8-Lead Plastic DIP
8-Lead Plastic SOIC
PACKAGE DESCRIPTION
8-Lead Plastic DIP
8-Lead Plastic SOIC
8-Lead Plastic DIP
8-Lead Plastic SOIC
OBSOLETE PACKAGE
8-Lead Ceramic DIP
–55°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
TEMPERATURE RANGE
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°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/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V ±5%, unless otherwise noted. (Notes 2 and 3)
SYMBOL
V
OD1
V
OD2
ΔV
OD
V
OC
Δ|V
OC
|
PARAMETER
Differential Driver Output Voltage (Unloaded)
Differential Driver Output Voltage (with Load)
Change in Magnitude of Driver Differential
Output Voltage for Complementary States
Driver Common Mode Output Voltage
Change in Magnitude of Driver Common Mode
Output Voltage for Complementary States
CONDITIONS
I
O
= 0
R = 50Ω (RS422)
R = 27Ω (RS485), Figure 1
R = 27Ω or R = 50Ω, Figure 1
R = 27Ω or R = 50Ω, Figure 1
R = 27Ω or R = 50Ω, Figure 1
l
l
l
l
l
l
ELECTRICAL CHARACTERISTICS
MIN
2
1.5
TYP
5
MAX
UNITS
V
V
V
V
V
V
485fm
5
0.2
3
0.2
2
For more information
www.linear.com/LTC485
LTC485
ELECTRICAL CHARACTERISTICS
SYMBOL
V
IH
V
IL
I
IN1
I
IN2
PARAMETER
Input High Voltage
Input Low Voltage
Input Current
Input Current (A, B)
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V ±5%, unless otherwise noted. (Notes 2 and 3)
CONDITIONS
DE, DI,
RE
DE, DI,
RE
DE, DI,
RE
DE = 0, V
CC
= 0V or 5.25V
C-, I-Grade
M-Grade
V
IN
= 12V
V
IN
= –7V
V
IN
= 12V
V
IN
= –7V
l
l
l
l
l
l
l
l
l
l
l
l
l
l
MIN
2
TYP
MAX
0.8
±2
1
–0.8
2
–1.6
UNITS
V
V
μA
mA
mA
mA
mA
V
mV
V
V
TH
ΔV
TH
V
OH
V
OL
I
OZR
R
IN
Differential Input Threshold Voltage for Receiver –7V ≤ V
CM
≤ 12V
Receiver Input Hysteresis
Receiver Output High Voltage
Receiver Output Low Voltage
Three-State (High Impedance) Output Current
at Receiver
Receiver Input Resistance
V
CM
= 0V
I
O
= –4mA, V
ID
= 200mV
I
O
= 4mA, V
ID
= –200mV
V
CC
= Max, 0.4V ≤ V
O
≤ 2.4V
–7V ≤ V
CM
≤ 12V (C-, I-Grade)
(M-Grade)
–0.2
70
3.5
0.2
0.4
±1
12
6
V
μA
kΩ
kΩ
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V ±5%, unless otherwise noted. (Notes 2 and 3)
SYMBOL
I
CC
I
OSD1
I
OSD2
I
OSR
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
|t
PLH
– t
PHL
| Differential Receiver Skew
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable from Low
Receiver Disable from High
C
RL
= 15pF (Figures 2 and 8) S1 Closed
C
RL
= 15pF (Figures 2 and 8) S2 Closed
C
RL
= 15pF (Figures 2 and 8) S1 Closed
C
RL
= 15pF (Figures 2 and 8) S2 Closed
PARAMETER
Supply Current
Driver Short-Circuit Current, V
OUT
= HIGH
Driver Short-Circuit Current, V
OUT
= LOW
Receiver Short-Circuit Current
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
C
L
= 100pF (Figures 4 and 6) S2 Closed
C
L
= 100pF (Figures 4 and 6) S1 Closed
C
L
= 15pF (Figures 4 and 6) S1 Closed
C
L
= 15pF (Figures 4 and 6) S2 Closed
R
DIFF
= 54Ω, CL1 = CL2 = 100pF,
(Figures 3 and 7)
CONDITIONS
No Load, Pins 2, 3, 4 = 0V or 5V
V
O
= – 7V
V
O
= 10V
0V ≤ V
O
≤ V
CC
R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF,
(Figures 3 and 5)
Outputs Enabled
Outputs Disabled
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
SWITCHING CHARACTERISTICS
MIN
TYP
500
300
MAX
900
500
250
250
85
50
50
10
25
70
70
70
70
200
200
50
50
50
50
UNITS
μA
μA
mA
mA
mA
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
35
35
7
10
10
3
100
100
30
30
5
15
40
40
40
40
30
30
90
90
13
20
20
20
20
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
reliability and lifetime.
Note 2:
All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to device ground unless
otherwise specified.
Note 3:
All typicals are given for V
CC
= 5V and T
A
= 25°C.
Note 4:
The LTC485 is guaranteed by design to be functional over a supply
voltage range of 5V ±10%. Data sheet parameters are guaranteed over the
tested supply voltage range of 5V ±5%.
For more information
www.linear.com/LTC485
3
485fm
LTC485
TYPICAL PERFORMANCE CHARACTERISTICS
Receiver Output Low Voltage
vs Output Current
36
32
OUTPUT CURRENT (mA)
28
24
20
16
12
8
4
0
0
0.5
1.5
1.0
OUTPUT VOLTAGE (V)
2.0
485 G01
Receiver Output High Voltage
vs Output Current
–18
–16
OUTPUT CURRENT (mA)
–14
OUTPUT VOLTAGE (V)
–12
–10
–8
–6
–4
–2
0
5
4
3
OUTPUT VOLTAGE (V)
2
485 G02
Receiver Output High Voltage
vs Temperature
4.8
4.6
4.4
4.2
4.0
3.8
3.6
3.4
3.2
3.0
–50
–25
25
50
0
75
TEMPERATURE (°C)
100
125
I = 8mA
T
A
= 25°C
T
A
= 25°C
485 G03
Receiver Output Low Voltage
vs Temperature
0.9
0.8
0.7
OUTPUT VOLTAGE (V)
0.6
0.5
0.4
0.3
0.2
0.1
0
–50
–25
25
50
0
75
TEMPERATURE (°C)
100
125
72
I = 8mA
64
OUTPUT CURRENT (mA)
56
48
40
32
24
16
8
0
Driver Differential Output Voltage
vs Output Current
T
A
= 25°C
DIFFERENTIAL VOLTAGE (V)
2.4
2.3
2.2
2.1
2.0
1.9
1.8
1.7
1.6
0
1
3
2
OUTPUT VOLTAGE (V)
4
485 G05
Driver Differential Output Voltage
vs Temperature
RI = 54
1.5
–50
–25
25
50
0
75
TEMPERATURE (°C)
100
125
485 G04
485 G06
Driver Output Low Voltage
vs Output Current
90
80
OUTPUT CURRENT (mA)
70
60
50
40
30
20
10
0
0
1
3
2
OUTPUT VOLTAGE (V)
4
485 G07
Driver Output High Voltage
vs Output Current
–108
–96
OUTPUT CURRENT (mA)
–84
–72
–60
–48
–36
–24
–12
0
0
1
3
2
OUTPUT VOLTAGE (V)
4
485 G08
TTL Input Threshold
vs Temperature
1.64
1.63
INPUT THRESHOLD VOLTAGE (V)
1.62
1.61
1.60
1.59
1.58
1.57
1.56
1.55
–50
–25
25
50
0
75
TEMPERATURE (°C)
100
125
T
A
= 25°C
T
A
= 25°C
485 G09
4
485fm
For more information
www.linear.com/LTC485
LTC485
TYPICAL PERFORMANCE CHARACTERISTICS
Receiver |t
PLH
– t
PHL
|
vs Temperature
7.5
7.0
6.5
6.0
TIME (ns)
5.5
5.0
4.5
4.0
3.5
3.0
–50
–25
25
50
0
75
TEMPERATURE (°C)
100
125
TIME (ns)
5.4
4.8
SUPPLY CURRENT (µA)
4.2
3.6
3.0
2.4
1.8
1.2
0.6
0
–50
–25
25
50
0
75
TEMPERATURE (°C)
100
125
Driver Skew vs Temperature
640
580
520
460
400
340
280
220
160
Supply Current vs Temperature
DRIVER ENABLED
DRIVER DISABLED
100
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
485 G10
485 G11
485 G12
PIN FUNCTIONS
RO (Pin 1):
Receiver Output. If the receiver output is en-
abled (RE low), then if A > B by 200mV, RO will be high.
If A < B by 200mV, then RO will be low.
RE
(Pin 2):
Receiver Output Enable. A low enables the
receiver output, RO. A high input forces the receiver output
into a high impedance state.
DE (Pin 3):
Driver Output Enable. A high on DE enables
the driver outputs, A and B, and the chip will function as
a line driver. A low input will force the driver outputs into
a high impedance state and the chip will function as a
line receiver.
DI (Pin 4):
Driver Input. If the driver outputs are enabled
(DE high), then a low on DI forces the outputs A low and
B high. A high on DI with the driver outputs enabled will
1. Introduction
Electronic scales are gradually replacing traditional measuring tools like springs and balances in everyday life, such as electronic price computing scales and electronic weigh...[详细]
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