LTC488/LTC489
Quad RS485 Line Receiver
FEATURES
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DESCRIPTION
The LTC
®
488 and LTC489 are low power differential bus/
line receivers designed for multipoint data transmission
standard RS485 applications with extended common
mode range (12V to –7V). They also meet the require-
ments of RS422.
The CMOS design offers significant power savings over
its bipolar counterpart without sacrificing ruggedness
against overload or ESD damage.
The receiver features three-state outputs, with the receiver
output maintaining high impedance over the entire com-
mon mode range.
The receiver has a fail-safe feature which guarantees a
high output state when the inputs are left open.
Both AC and DC specifications are guaranteed 4.75V to
5.25V supply voltage range.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
Low Power: I
CC
= 7mA Typ
Designed for RS485 or RS422 Applications
Single 5V Supply
–7V to 12V Bus Common Mode Range Permits ±7V
Ground Difference Between Devices on the Bus
60mV Typical Input Hysteresis
Receiver Maintains High Impedance in Three-State or
with the Power Off
28ns Typical Receiver Propagation Delay
Pin Compatible with the SN75173 (LTC488)
Pin Compatible with the SN75175 (LTC489)
APPLICATIONS
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Low Power RS485/RS422 Receivers
Level Translator
TYPICAL APPLICATION
EN
EN
EN
2
DI
DRIVER
1/4 LTC486
120Ω
120Ω
1
4000 FT 24 GAUGE TWISTED PAIR
EN12
EN12
2
DI
DRIVER
1/4 LTC487
120Ω
120Ω
1
4000 FT 24 GAUGE TWISTED PAIR
4
RECEIVER
1/4 LTC489
3
RO
4
12
RECEIVER
1/4 LTC488
3
RO
EN
4889 TA01
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LTC488/LTC489
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Supply Voltage (V
CC
) ................................................12V
Control Input Currents .......................... –25mA to 25mA
Control Input Voltages ..................–0.5V to (V
CC
+ 0.5V)
Receiver Input Voltages ..........................................±14V
Receiver Output Voltages ..............–0.5V to (V
CC
+ 0.5V)
Operating Temperature Range
LTC488C/LTC489C ................................... 0°C to 70°C
LTC488I/LTC489I.................................. –40°C to 85°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
PIN CONFIGURATION
LTC488
TOP VIEW
B1
A1
RO1
EN
RO2
A2
B2
GND
1
2
3
4
5
6
7
8
R
R
R
R
16 V
CC
15 B4
14 A4
13 RO4
12
EN
11 RO3
10 A3
9
B3
B1 1
A1 2
RO1 3
EN 4
RO2 5
A2 6
B2 7
GND 8
R
R
R
R
LTC488
TOP VIEW
16 V
CC
15 B4
14 A4
13 RO4
12
EN
11 RO3
10 A3
9
B3
N PACKAGE
16-LEAD PLASTIC DIP
T
JMAX
= 150°C,
θ
JA
= 70°C/W
LTC489
TOP VIEW
B1
A1
RO1
EN12
RO2
A2
B2
GND
1
2
3
4
5
6
7
8
R
R
R
R
16 V
CC
15 B4
14 A4
13 RO4
12 EN34
11 RO3
10 A3
9
B3
LTC489
SW PACKAGE
16-LEAD PLASTIC (WIDE) SO
T
JMAX
= 150°C,
θ
JA
= 90°C/W
TOP VIEW
B1 1
A1 2
RO1 3
EN12 4
RO2 5
A2 6
B2 7
GND 8
R
R
R
R
16 V
CC
15 B4
14 A4
13 RO4
12 EN34
11 RO3
10 A3
9
B3
N PACKAGE
16-LEAD PLASTIC DIP
T
JMAX
= 150°C,
θ
JA
= 70°C/W
SW PACKAGE
16-LEAD PLASTIC (WIDE) SO
T
JMAX
= 150°C,
θ
JA
= 90°C/W
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LTC488/LTC489
ORDER INFORMATION
LEAD FREE FINISH
LTC488CN#PBF
LTC488CSW#PBF
LTC488IN#PBF
LTC488ISW#PBF
LTC489CN#PBF
LTC489CSW#PBF
LTC489IN#PBF
LTC489ISW#PBF
TAPE AND REEL
LTC488CN#TRPBF
LTC488CSW#TRPBF
LTC488IN#TRPBF
LTC488ISW#TRPBF
LTC489CN#TRPBF
LTC489CSW#TRPBF
LTC489IN#TRPBF
LTC489ISW#TRPBF
PART MARKING
LTC488CN
LTC488CSW
LTC488IN
LTC488ISW
LTC489CN
LTC489CSW
LTC489IN
LTC489ISW
PACKAGE DESCRIPTION
16-Lead Plastic DIP
16-Lead Plastic SO
16-Lead Plastic DIP
16-Lead Plastic SO
16-Lead Plastic DIP
16-Lead Plastic SO
16-Lead Plastic DIP
16-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
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based finish parts.
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/
DC ELECTRICAL CHARACTERISTICS
SYMBOL
V
INH
V
INL
I
IN1
I
IN2
V
TH
ΔV
TH
V
OH
V
OL
I
OZR
I
CC
R
IN
I
OSR
t
PLH
t
PHL
t
SKD
PARAMETER
Input High Voltage
Input Low Voltage
Input Current
Input Current (A, B)
Differential Input Threshold Voltage for Receiver
Receiver Input Hysteresis
Receiver Output High Voltage
Receiver Output Low Voltage
Three-State Output Current at Receiver
Supply Current
Receiver Input Resistance
Receiver Short-Circuit Current
Receiver Input to Output
Receiver Input to Output
| t
PLH
– t
PHL
|
Differential Receiver Skew
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V (Notes 2, 3), unless otherwise noted.
CONDITIONS
EN,
EN,
EN12, EN34
EN,
EN,
EN12, EN34
EN,
EN,
EN12, EN34
V
CC
= 0V or 5.25V, V
IN
= 12V
V
CC
= 0V or 5.25V, V
IN
= – 7V
–7V ≤ V
CM
≤ 12V
V
CM
= 0V
I
O
= –4mA, V
ID
= 0.2V
I
O
= 4mA, V
ID
= –0.2V
V
CC
= Max 0.4V ≤ V
O
≤ 2.4V
No Load, Digital Pins = GND or V
CC
–7V ≤ V
CM
≤ 12V, V
CC
= 0V
0V ≤ V
O
≤ V
CC
C
L
= 15pF (Figures 1, 3)
C
L
= 15pF (Figures 1, 3)
C
L
= 15pF (Figures 1, 3)
l
l
l
l
l
l
l
l
l
l
l
l
l
l
MIN
2.0
TYP
MAX
0.8
±2
1.0
–0.8
UNITS
V
V
μA
mA
mA
V
mV
V
–0.2
60
3.5
0.2
0.4
±1
7
12
7
12
12
28
28
4
85
55
55
10
V
μA
mA
kΩ
mA
ns
ns
ns
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% (Notes 2, 3), unless otherwise noted.
SYMBOL
t
ZL
t
ZH
t
LZ
t
HZ
PARAMETER
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable from Low
Receiver Disable from High
CONDITIONS
C
L
= 15pF (Figures 2, 4) S1 Closed
C
L
= 15pF (Figures 2, 4) S2 Closed
C
L
= 15pF (Figures 2, 4) S1 Closed
C
L
= 15pF (Figures 2, 4) S2 Closed
l
l
l
l
MIN
TYP
30
30
30
30
MAX
60
60
60
60
UNITS
ns
ns
ns
ns
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.
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LTC488/LTC489
TYPICAL PERFORMANCE CHARACTERISTICS
Receiver Output Low Voltage vs
Temperature at I = 8mA
0.9
0.8
0.7
OUTPUT VOLTAGE (V)
0.6
0.5
0.4
0.3
0.2
0.1
0
–50
–25
0
75
25
50
TEMPERATURE (°C)
100
125
OUTPUT VOLTAGE (V)
4.8
4.6
OUTPUT CURRENT (mA)
4.4
4.2
4.0
3.8
3.6
3.4
3.2
3.0
–50
–25
0
75
50
25
TEMPERATURE (°C)
100
125
Receiver Output High Voltage vs
Temperature at I = 8mA
–18
–16
–14
–12
–10
–8
–6
–4
–2
0
Receiver Output High Voltage vs
Output Current at T
A
= 25°C
5
4
3
OUTPUT VOLTAGE (V)
4889 G03
2
4889 G01
4889 G02
Receiver Output Low Voltage vs
Output Current at T
A
= 25°C
36
INPUT THRESHOLD VOLTAGE (V)
32
OUTPUT CURRENT (mA)
28
24
20
16
12
8
4
0
0
0.5
1.5
1.0
OUTPUT VOLTAGE (V)
2.0
4889 G04
TTL Input Threshold vs
Temperature
1.63
1.61
1.59
1.57
1.55
–50
–25
0
75
25
50
TEMPERATURE (°C)
100
125
8889 G05
Receiver
|
t
PLH
– t
PHL
|
vs
Temperature
5
SUPPLY CURRENT (mA)
7.0
Supply Current vs Temperature
4
TIME (ns)
6.6
3
6.2
2
5.8
1
–50
–25
0
75
25
50
TEMPERATURE (°C)
100
125
5.4
–50
–25
0
75
25
50
TEMPERATURE (°C)
100
125
4889 G06
4889 G07
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LTC488/LTC489
PIN FUNCTIONS
B 1 (Pin 1):
Receiver 1 Input.
A1 (Pin 2):
Receiver 1 Input.
RO1 (Pin 3):
Receiver 1 Output. If the receiver output
is enabled, then if A > B by 200mV, RO1 will be high. If
A < B by 200mV, then RO1 will be low.
EN (Pin 4) LTC488:
Receiver Output Enabled. See Function
Table for details.
EN12 (Pin 4) LTC489:
Receiver 1, Receiver 2 Output
Enabled. See Function Table for details.
RO2 (Pin 5):
Receiver 2 Output. Refer to RO1.
A2 (Pin 6):
Receiver 2 Input.
B2 (Pin 7):
Receiver 2 Input.
GND (Pin 8):
Ground Connection.
B3 (Pin 9):
Receiver 3 Input.
A3 (Pin 10):
Receiver 3 Input.
RO3 (Pin 11):
Receiver 3 Output. Refer to RO1.
EN
(Pin 12) LTC488:
Receiver Output Disabled. See Func-
tion Table for details.
EN34 (Pin 12) LTC489:
Receiver 3, Receiver 4 output
enabled. See Function Table for details.
RO4 (Pin 13):
Receiver 4 Output. Refer to RO1.
A4 (Pin 14):
Receiver 4 Input.
B4 (Pin 15):
Receiver 4 Input.
V
CC
(Pin 16):
Positive Supply; 4.75V ≤ V
CC
≤ 5.25V.
FUNCTION TABLES
LTC488
DIFFERENTIAL
A–B
V
ID
≥ 0.2V
–0.2V < V
ID
< 0.2V
V
ID
≤ 0.2V
X
EN
H
X
H
X
H
X
L
ENABLES
EN
X
L
X
L
X
L
H
OUTPUT
RO
H
H
?
?
L
L
Z
LTC489
DIFFERENTIAL
A–B
V
ID
≥ 0.2V
–0.2V < V
ID
< 0.2V
V
ID
≤ 0.2V
X
H: High Level
L: Low Level
X: Irrelevant
ENABLES
EN12 or EN34
H
H
H
L
?: Indeterminate
Z: High Impedance (Off)
OUTPUT
RO
H
?
L
Z
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测试/测量
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