LTC485
Low Power RS485
Interface Transceiver
FEATURES
DESCRIPTION
Low Power: ICC = 300μA Typ
nn Designed for RS485 Interface Applications
nn Single 5V Supply
nn –7V to 12V Bus Common Mode Range Permits
±7V Ground Difference Between Devices on the Bus
nn Thermal Shutdown Protection
nn Power-Up/Down Glitch-Free Driver Outputs
Permit Live Insertion or Removal of Transceiver
nn Driver Maintains High Impedance in Three-State
or with the Power Off
nn Combined Impedance of a Driver Output and
Receiver Allows Up to 32 Transceivers on the Bus
nn 70mV Typical Input Hysteresis
nn 30ns Typical Driver Propagation Delays
with 5ns Skew for Up to 2.5MB Operation
nn Pin Compatible with ±60V Protected LTC2862
The LTC®485 is a low power differential bus/line transceiver designed for multipoint data transmission standard
RS485 applications with extended common mode range
(12V to –7V). It also meets the requirements of RS422.
nn
The CMOS design offers significant power savings over
its bipolar counterpart without sacrificing ruggedness
against overload or ESD damage.
The driver and receiver feature three-state outputs, with
the driver outputs maintaining high impedance over the
entire common mode range. Excessive power dissipation caused by bus contention or faults is prevented by a
thermal shutdown circuit which forces the driver outputs
into a high impedance state.
The receiver has a fail-safe feature which guarantees a
high output state when the inputs are left open.
The LTC485 is fully specified over the commercial and
extended industrial temperature range.
APPLICATIONS
Low Power RS485/RS422 Transceiver
nn Level Translator
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
nn
TYPICAL APPLICATION
Driver Outputs
RO1
R
VCC1
RE1
DI1
RO2
A
Rt
DE1
D
R
GND1
VCC2
Rt
RE2
DE2
DI2
D
B
GND2
485 TA01a
485 TA01b
485fm
For more information www.linear.com/LTC485
1
LTC485
ABSOLUTE MAXIMUM RATINGS
PIN CONFIGURATION
(Note 1)
Supply Voltage...........................................................12V
Control Input Voltages..................... –0.5V to VCC + 0.5V
Driver Input Voltage......................... –0.5V to VCC + 0.5V
Driver Output Voltage.............................................. ±14V
Receiver Input Voltage............................................. ±14V
Receiver Output Voltages................ –0.5V to VCC + 0.5V
Operating Temperature Range
LTC485I......................................... –40°C ≤ TA ≤ 85°C
LTC485C.............................................0°C ≤ TA ≤ 70°C
LTC485M (OBSOLETE).................–55°C ≤ TA ≤ 125°C
Lead Temperature (Soldering, 10 sec).................... 300°C
Storage Temperature Range................... –65°C to 150°C
TOP VIEW
RO 1
8
VCC
RE 2
7
B
DE 3
6
A
5
GND
R
D
DI 4
N8 PACKAGE
8-LEAD PLASTIC DIP
S8 PACKAGE
8-LEAD PLASTIC SOIC
J8 PACKAGE
8-LEAD CERAMIC DIP
OBSOLETE PACKAGE
TJMAX = 125°C, θJA = 100°C/W (N)
TJMAX = 150°C, θJA = 150°C/W (S)
TJMAX = 155°C, θJA = 100°C/W (J)
ORDER INFORMATION
http://www.linear.com/product/LTC485#orderinfo
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC485CN8#PBF
NA
LTC485CN8
8-Lead Plastic DIP
0°C to 70°C
LTC485CS8#PBF
LTC485CS8#TRPBF
485
8-Lead Plastic SOIC
0°C to 70°C
LTC485IN8#PBF
NA
LTC485IN8
8-Lead Plastic DIP
–40°C to 85°C
LTC485IS8#PBF
LTC485IS8#TRPBF
485I
8-Lead Plastic SOIC
–40°C to 85°C
LEAD BASED FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC485CN8
NA
LTC485CN8
8-Lead Plastic DIP
0°C to 70°C
LTC485CS8
LTC485CS8#TR
485
8-Lead Plastic SOIC
0°C to 70°C
LTC485IN8
NA
LTC485IN8
8-Lead Plastic DIP
–40°C to 85°C
LTC485IS8
LTC485IS8#TR
485I
8-Lead Plastic SOIC
–40°C to 85°C
OBSOLETE PACKAGE
LTC485MJ8
NA
LTC485MJ8
8-Lead Ceramic DIP
–55°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/
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.
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V ±5%, unless otherwise noted. (Notes 2 and 3)
SYMBOL
PARAMETER
CONDITIONS
MIN
VOD1
Differential Driver Output Voltage (Unloaded)
IO = 0
l
VOD2
Differential Driver Output Voltage (with Load)
R = 50Ω (RS422)
R = 27Ω (RS485), Figure 1
l
l
ΔVOD
Change in Magnitude of Driver Differential
Output Voltage for Complementary States
R = 27Ω or R = 50Ω, Figure 1
VOC
Driver Common Mode Output Voltage
Δ|VOC|
Change in Magnitude of Driver Common Mode
Output Voltage for Complementary States
2
TYP
MAX
5
2
1.5
UNITS
V
5
V
V
l
0.2
V
R = 27Ω or R = 50Ω, Figure 1
l
3
V
R = 27Ω or R = 50Ω, Figure 1
l
0.2
V
485fm
For more information www.linear.com/LTC485
LTC485
ELECTRICAL
CHARACTERISTICS
The
l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V ±5%, unless otherwise noted. (Notes 2 and 3)
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
VIH
Input High Voltage
DE, DI, RE
l
VIL
Input Low Voltage
DE, DI, RE
l
0.8
2
UNITS
V
V
IIN1
Input Current
DE, DI, RE
l
±2
μA
IIN2
Input Current (A, B)
DE = 0, VCC = 0V or 5.25V VIN = 12V
C-, I-Grade
VIN = –7V
l
l
1
–0.8
mA
mA
M-Grade VIN = 12V
VIN = –7V
l
l
2
–1.6
mA
mA
0.2
V
VTH
Differential Input Threshold Voltage for Receiver –7V ≤ VCM ≤ 12V
l
ΔVTH
Receiver Input Hysteresis
VCM = 0V
l
VOH
Receiver Output High Voltage
IO = –4mA, VID = 200mV
l
–0.2
70
mV
3.5
V
VOL
Receiver Output Low Voltage
IO = 4mA, VID = –200mV
l
0.4
V
IOZR
Three-State (High Impedance) Output Current
at Receiver
VCC = Max, 0.4V ≤ VO ≤ 2.4V
l
±1
μA
RIN
Receiver Input Resistance
–7V ≤ VCM ≤ 12V (C-, I-Grade)
(M-Grade)
l
l
12
6
kΩ
kΩ
SWITCHING CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V ±5%, unless otherwise noted. (Notes 2 and 3)
SYMBOL
PARAMETER
CONDITIONS
MIN
ICC
Supply Current
No Load, Pins 2, 3, 4 = 0V or 5V
IOSD1
Driver Short-Circuit Current, VOUT = HIGH
VO = – 7V
l
IOSD2
Driver Short-Circuit Current, VOUT = LOW
VO = 10V
l
Outputs Enabled
Outputs Disabled
TYP
MAX
UNITS
500
300
900
500
μA
μA
35
100
250
mA
35
100
250
mA
85
mA
50
ns
l
l
IOSR
Receiver Short-Circuit Current
0V ≤ VO ≤ VCC
l
7
tPLH
Driver Input to Output
l
10
30
tPHL
Driver Input to Output
RDIFF = 54Ω, CL1 = CL2 = 100pF,
(Figures 3 and 5)
l
10
30
50
ns
tSKEW
Driver Output to Output
l
5
10
ns
tr, tf
Driver Rise or Fall Time
l
15
25
ns
tZH
Driver Enable to Output High
CL = 100pF (Figures 4 and 6) S2 Closed
l
40
70
ns
tZL
Driver Enable to Output Low
CL = 100pF (Figures 4 and 6) S1 Closed
l
40
70
ns
tLZ
Driver Disable Time from Low
CL = 15pF (Figures 4 and 6) S1 Closed
l
40
70
ns
tHZ
Driver Disable Time from High
CL = 15pF (Figures 4 and 6) S2 Closed
l
40
70
ns
tPLH
Receiver Input to Output
RDIFF = 54Ω, CL1 = CL2 = 100pF,
(Figures 3 and 7)
l
30
90
200
ns
l
30
90
200
tPHL
3
ns
tSKD
|tPLH – tPHL| Differential Receiver Skew
tZL
Receiver Enable to Output Low
CRL = 15pF (Figures 2 and 8) S1 Closed
l
20
50
ns
tZH
Receiver Enable to Output High
CRL = 15pF (Figures 2 and 8) S2 Closed
l
20
50
ns
tLZ
Receiver Disable from Low
CRL = 15pF (Figures 2 and 8) S1 Closed
l
20
50
ns
tHZ
Receiver Disable from High
CRL = 15pF (Figures 2 and 8) S2 Closed
l
20
50
ns
l
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.
13
ns
Note 3: All typicals are given for VCC = 5V and TA = 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
485fm
3
LTC485
TYPICAL PERFORMANCE CHARACTERISTICS
Receiver Output Low Voltage
vs Output Current
–18
TA = 25°C
32
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
24
20
16
12
8
4
0
0.5
0
4.4
–12
–10
–8
–6
3.2
4
3
OUTPUT VOLTAGE (V)
5
0.5
0.4
0.3
0.2
2.4
TA = 25°C
56
48
40
32
24
16
0
125
0
1
40
30
20
10
1.7
4
–25
25
50
0
75
TEMPERATURE (°C)
100
1.64
TA = 25°C
–84
–72
–60
–48
–36
–24
0
125
TTL Input Threshold
vs Temperature
–12
485 G07
4
1.8
485 G06
1.63
INPUT THRESHOLD VOLTAGE (V)
50
3
2
OUTPUT VOLTAGE (V)
1.9
1.5
–50
4
3
2
OUTPUT VOLTAGE (V)
–96
60
1
2.0
1.6
–108
70
0
2.1
Driver Output High Voltage
vs Output Current
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
80
125
2.2
485 G05
Driver Output Low Voltage
vs Output Current
TA = 25°C
100
RI = 54Ω
2.3
485 G04
90
25
50
0
75
TEMPERATURE (°C)
Driver Differential Output Voltage
vs Temperature
8
0.1
100
–25
485 G03
DIFFERENTIAL VOLTAGE (V)
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE (V)
0.7
0.6
0
3.0
–50
2
Driver Differential Output Voltage
vs Output Current
64
25
50
0
75
TEMPERATURE (°C)
3.6
–2
72
–25
3.8
485 G02
I = 8mA
0
–50
4.0
3.4
Receiver Output Low Voltage
vs Temperature
0.8
4.2
–4
485 G01
0.9
I = 8mA
4.6
–14
0
2.0
1.5
1.0
OUTPUT VOLTAGE (V)
4.8
TA = 25°C
–16
28
Receiver Output High Voltage
vs Temperature
OUTPUT VOLTAGE (V)
36
Receiver Output High Voltage
vs Output Current
0
1
3
2
OUTPUT VOLTAGE (V)
4
485 G08
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
485 G09
485fm
For more information www.linear.com/LTC485
LTC485
TYPICAL PERFORMANCE CHARACTERISTICS
Driver Skew vs Temperature
Supply Current vs Temperature
5.4
640
7.0
4.8
580
6.5
4.2
520
6.0
3.6
5.5
5.0
3.0
2.4
4.5
1.8
4.0
1.2
3.5
0.6
3.0
–50
–25
25
50
0
75
TEMPERATURE (°C)
100
125
SUPPLY CURRENT (µA)
7.5
TIME (ns)
TIME (ns)
Receiver |tPLH – tPHL|
vs Temperature
0
–50
DRIVER ENABLED
460
400
340
DRIVER DISABLED
280
220
160
–25
25
50
0
75
TEMPERATURE (°C)
485 G10
100
125
100
–50
–25
0
25
50
75
TEMPERATURE (°C)
485 G11
100
125
485 G12
PIN FUNCTIONS
RO (Pin 1): Receiver Output. If the receiver output is enabled (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
force A high and B low.
GND (Pin 5): Ground Connection.
A (Pin 6): Driver Output/Receiver Input.
B (Pin 7): Driver Output/Receiver Input.
VCC (Pin 8): Positive Supply; 4.75 < VCC < 5.25.
485fm
For more information www.linear.com/LTC485
5
LTC485
TEST CIRCUITS
A
R
RECEIVER
OUTPUT
VOD
CRL
15pF
VOC
R
S1
TEST POINT
1k
1k
VCC
S2
485 F02
B
485 F01
Figure 1. Driver DC Test Load
Figure 2. Receiver Timing Test Load
3V
DE
A
DI
CL1
RDIFF
B
CL2
A
S1
RO
B
RE
VCC
500Ω
OUTPUT
UNDER TEST
S2
15pF
CL
485 F04
485 F03
Figure 3. Driver/Receiver Timing Test Circuit
Figure 4. Driver Timing Test Load #2
SWITCHING TIME WAVEFORMS
3V
1.5V
DI
f = 1MHz, tr ≤ 10ns, tf ≤ 10ns
0V
tPLH
B
A
VO
0V
–VO
1.5V
1/2 VO
tPLH
VO
tSKEW
1/2 VO
10%
80%
tSKEW
90%
VDIFF = V(A) – V(B)
tr
20%
tf
485 F05
Figure 5. Driver Propagation Delays
6
485fm
For more information www.linear.com/LTC485
LTC485
SWITCHING TIME WAVEFORMS
3V
1.5V
DI
tLZ
tZL
5V
A, B
2.3V
OUTPUT NORMALLY LOW
0.5V
2.3V
OUTPUT NORMALLY HIGH
0.5V
VOL
A, B
1.5V
f = 1MHz, tr ≤ 10ns, tf ≤ 10ns
0V
VOH
0V
tHZ
tZH
485 F06
Figure 6. Driver Enable and Disable Times
R
VOH
1.5V
VOL
f = 1MHz, tr ≤ 10ns, tf ≤ 10ns
tPHL
VOD2
A, B
–VOD2
0V
1.5V
OUTPUT
tPLH
INPUT
485 F07
Figure 7. Receiver Propagation Delays
3V
1.5V
RE
R
tLZ
tZL
5V
R
0V
1.5V
f = 1MHz, tr ≤ 10ns, tf ≤ 10ns
0V
1.5V
OUTPUT NORMALLY LOW
0.5V
1.5V
OUTPUT NORMALLY HIGH
0.5V
tHZ
tZH
485 F08
Figure 8. Receiver Enable and Disable Times
FUNCTION TABLES
LTC485 Receiving
LTC485 Transmitting
INPUTS
INPUTS
OUTPUTS
OUTPUTS
RE
DE
DI
LINE
CONDITION
X
1
1
No Fault
X
1
0
No Fault
1
0
0
0
≤ –0.2V
0
X
0
X
X
Z
Z
0
0
Inputs Open
1
X
1
X
Fault
Z
Z
1
0
X
Z
B
0
A
RE
DE
A–B
R
1
0
0
≥ 0.2V
1
485fm
For more information www.linear.com/LTC485
7
LTC485
APPLICATIONS INFORMATION
Basic Theory of Operation
Previous RS485 transceivers have been designed using
bipolar technology because the common mode range
of the device must extend beyond the supplies and the
device must be immune to ESD damage and latchup.
Unfortunately, the bipolar devices draw a large amount of
supply current, which is unacceptable for the numerous
applications that require low power consumption. The
LTC485 is the first CMOS RS485/RS422 transceiver which
features ultralow power consumption without sacrificing
ESD and latchup immunity.
The LTC485 uses a proprietary driver output stage, which
allows a common-mode range that extends beyond the
power supplies while virtually eliminating latchup and
providing excellent ESD protection. Figure 9 shows the
LTC485 output stage while Figure 10 shows a conventional
CMOS output stage.
When the conventional CMOS output stage of Figure 10
enters a high impedance state, both the P-channel (P1)
and the N-channel (N1) are turned off. If the output is
then driven above VCC or below ground, the P + /N-well
diode (D1) or the N + /P-substrate diode (D2) respectively
will turn on and clamp the output to the supply. Thus,
the output stage is no longer in a high impedance state
and is not able to meet the RS485 common mode range
requirement. In addition, the large amount of current
flowing through either diode will induce the well known
CMOS latchup condition, which could destroy the device.
The LTC485 output stage of Figure 9 eliminates these
problems by adding two Schottky diodes, SD3 and SD4.
The Schottky diodes are fabricated by a proprietary modification to the standard N-well CMOS process. When the
output stage is operating normally, the Schottky diodes
are forward biased and have a small voltage drop across
them. When the output is in the high impedance state and
is driven above VCC or below ground, the parasitic diodes
D1 or D2 still turn on, but SD3 or SD4 will reverse bias
and prevent current from flowing into the N-well or the
substrate. Thus, the high impedance state is maintained
even with the output voltage beyond the supplies. With
no minority carrier current flowing into the N-well or
substrate, latchup is virtually eliminated under power-up
or power-down conditions.
VCC
VCC
SD3
P1
P1
D1
D1
OUTPUT
LOGIC
N1
N1
D2
485 F09
Figure 9. LTC485 Output Stage
8
OUTPUT
LOGIC
SD4
D2
485 F10
Figure 10. Conventional CMOS Output Stage
485fm
For more information www.linear.com/LTC485
LTC485
APPLICATIONS INFORMATION
The LTC485 output stage will maintain a high impedance
state until the breakdown of the N-channel or P-channel
is reached when going positive or negative respectively.
The output will be clamped to either VCC or ground by a
Zener voltage plus a Schottky diode drop, but this voltage
is way beyond the RS485 operating range. This clamp
protects the MOS gates from ESD voltages well over
2000V. Because the ESD injected current in the N-well or
substrate consists of majority carriers, latchup is prevented
by careful layout techniques.
Propagation Delay
Many digital encoding schemes are dependent upon the
difference in the propagation delay times of the driver and
the receiver. Using the test circuit of Figure 13, Figures 11
and 12 show the typical LTC485 receiver propagation delay.
The receiver delay times are:
|tPLH – tPHL| = 9ns Typ, VCC = 5V
The driver skew times are:
Skew = 5ns Typ, VCC = 5V
10ns Max, VCC = 5V, TA = –40°C to 85°C
A
A
DRIVER
OUTPUTS
DRIVER
OUTPUTS
B
RECEIVER
RO
OUTPUTS
B
RECEIVER
RO
OUTPUTS
485 F11
485 F12
Figure 11. Receiver tPHL
Figure 12. Receiver tPLH
100pF
TTL IN
tr, tf < 6ns
D
BR
R
R
100Ω
RECEIVER
OUT
485 F13
100pF
Figure 13. Receiver Propagation Delay Test Circuit
485fm
For more information www.linear.com/LTC485
9
LTC485
APPLICATIONS INFORMATION
LTC485 Line Length vs Data Rate
The maximum line length allowable for the RS422/RS485
standard is 4000 feet.
Figures 17 and 18 show that the LTC485 is able to comfortably drive 4000 feet of wire at 110kHz.
100Ω
C
A
LTC485
LTC485
D
B
NOISE
GENERATOR
TTL
IN
RO
TTL
OUT
COMMON MODE
VOLTAGE (A + B)/2
4000 FT 26AWG
TWISTED PAIR
DI
485 F14
Figure 14. Line Length Test Circuit
485 F17
Figure 17. System Common Mode Voltage at 110kHz
Using the test circuit in Figure 14, Figures 15 and 16 show
that with ~20VP-P common mode noise injected on the
line, the LTC485 is able to reconstruct the data stream at
the end of 4000 feet of twisted pair wire.
RO
DIFFERENTIAL
VOLTAGE (A – B)
DI
RO
COMMON MODE
VOLTAGE (A + B)/2
485 F18
Figure 18. System Differential Voltage at 110kHz
DI
485 F15
When specifying line length vs maximum data rate the
curve in Figure 19 should be used.
Figure 15. System Common Mode Voltage at 19.2kHz
CABLE LENGTH (FT)
10k
RO
DIFFERENTIAL
VOLTAGE A – B
1k
100
DI
10
10k
485 F16
Figure 16. System Differential Voltage at 19.2kHz
10
100k
1M 2.5M
MAXIMUM DATA RATE
10M
485 F19
Figure 19. Cable Length vs Maximum Data Rate
485fm
For more information www.linear.com/LTC485
LTC485
TYPICAL APPLICATION
Typical RS485 Network
Rt
Rt
485 TA02
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/product/LTC485#packaging for the most recent package drawings.
J8 Package
8-Lead CERDIP (Narrow .300 Inch, Hermetic)
(Reference LTC DWG # 05-08-1110)
CORNER LEADS OPTION
(4 PLCS)
.023 – .045
(0.584 – 1.143)
HALF LEAD
OPTION
.045 – .068
(1.143 – 1.650)
FULL LEAD
OPTION
.005
(0.127)
MIN
.405
(10.287)
MAX
8
7
6
5
.025
(0.635)
RAD TYP
.220 – .310
(5.588 – 7.874)
1
.300 BSC
(7.62 BSC)
2
3
4
.200
(5.080)
MAX
.015 – .060
(0.381 – 1.524)
.008 – .018
(0.203 – 0.457)
0° – 15°
NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE
OR TIN PLATE LEADS
.045 – .065
(1.143 – 1.651)
.014 – .026
(0.360 – 0.660)
.100
(2.54)
BSC
.125
3.175
MIN
J8 0801
OBSOLETE PACKAGE
485fm
For more information www.linear.com/LTC485
11
LTC485
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/product/LTC485#packaging for the most recent package drawings.
N Package
8-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510 Rev I)
.300 – .325
(7.620 – 8.255)
(
+.035
.325 –.015
+0.889
8.255
–0.381
.130 ±.005
(3.302 ±0.127)
.045 – .065
(1.143 – 1.651)
.065
(1.651)
TYP
.008 – .015
(0.203 – 0.381)
)
.400*
(10.160)
MAX
8
7
6
5
1
2
3
4
.255 ±.015*
(6.477 ±0.381)
.120
(3.048) .020
MIN
(0.508)
MIN
.018 ±.003
.100
(2.54)
BSC
(0.457 ±0.076)
N8 REV I 0711
NOTE:
1. DIMENSIONS ARE
INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610 Rev G)
.189 – .197
(4.801 – 5.004)
NOTE 3
.045 ±.005
.050 BSC
8
.245
MIN
.160 ±.005
.010 – .020
× 45°
(0.254 – 0.508)
2
.053 – .069
(1.346 – 1.752)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
.014 – .019
(0.355 – 0.483)
TYP
INCHES
(MILLIMETERS)
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
4. PIN 1 CAN BE BEVEL EDGE OR A DIMPLE
12
5
.150 – .157
(3.810 – 3.988)
NOTE 3
1
RECOMMENDED SOLDER PAD LAYOUT
.008 – .010
(0.203 – 0.254)
6
.228 – .244
(5.791 – 6.197)
.030 ±.005
TYP
NOTE:
1. DIMENSIONS IN
7
3
4
.004 – .010
(0.101 – 0.254)
.050
(1.270)
BSC
SO8 REV G 0212
485fm
For more information www.linear.com/LTC485
LTC485
REVISION HISTORY
(Revision history begins at Rev I)
REV
DATE
DESCRIPTION
PAGE NUMBER
I
4/11
Removed lead free version of LTC485MJ8 from Order Information section.
J
01/14
Modified to account for high temperature leakage in M-grade.
K
02/14
Remove tape and reel option for DIP package in Order Information section.
L
07/16
Added storage temperature
M
02/17
Obsoleted J8 package
2
1, 3
2
2
1-14
485fm
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representaFor more
information
www.linear.com/LTC485
tion that the interconnection
of its circuits
as described
herein will not infringe on existing patent rights.
13
LTC485
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC486/LTC487
Low Power Quad RS485 Drivers
110μA Supply Current
LTC488/LTC489
Low Power Quad RS485 Receivers
7mA Supply Current
LTC490/LTC491
Low Power Full-Duplex RS485 Transceivers
300μA Supply Current
LTC1480
3.3V Supply RS485 Transceiver
Lower Supply Voltage
LTC1481
Low Power RS485 Transceiver with Shutdown
Lowest Power
LTC1482
RS485 Transceiver with Carrier Detect
±15kV ESD, Fail-Safe
LTC1483
Low Power, Low EMI RS485 Transceiver
Slew Rate Limited Driver Outputs, Lowest Power
LTC1484
RS485 Transceiver with Fail-Safe
±15kV ESD, MSOP Package
LTC1485
10Mbps RS485 Transceiver
High Speed
LTC1518/LTC1519
52Mbps Quad RS485 Receivers
Higher Speed, LTC488/LTC489 Pin-Compatible
LTC1520
LVDS-Compatible Quad Receiver
100mV Threshold, Low Channel-to-Channel Skew
LTC1535
2500V Isolated RS485 Transceiver
Full-Duplex, Self-Powered Using External Transformer
LTC1685
52Mbps RS485 Transceiver
Industry-Standard Pinout, 500ps Propagation Delay Skew
LTC1686/LTC1687
52Mbps Full-Duplex RS485 Transceivers
LTC490/LTC491 Pin Compatible
LTC1688/LTC1689
100Mbps Quad RS485 Drivers
Highest Speed, LTC486/LTC487 Pin Compatible
LTC1690
Full-Duplex RS485 Transceiver with Fail-Safe
±15kV ESD, LTC490 Pin Compatible
LT1785/LT1785A
±60V Protected RS485 Transceivers
±15kV ESD, Fail-Safe (LT1785A)
LT1791/LT1791A
±60V Protected Full-Duplex RS485 Transceivers
±15kV ESD, Fail-Safe (LT1791A)
LTC2850/LTC2851/
LTC2852
3.3V Supply RS485 Transceivers
±15kV ESD, 20Mbps, 900µA Supply Current, Fail-Safe
LTC2854/LTC2855
3.3V Supply RS485 Transceivers
±15kV ESD, 20Mbps, 900µA Supply Current,
Integrated Switchable Termination
LTC2856/LTC2857/
LTC2858
20Mbps RS485 Transceivers
±15kV ESD, 900µA Supply Current, Fail-Safe
LTC2859/LTC2861
20Mbps RS485 Transceivers
±15kV ESD, 900µA Supply Current, Integrated Switchable Termination
LTC2862/LTC2863/
LTC2864/LTC2865
±60V Protected RS485 Transceivers
3V to 5.5V Supply, ±15kV ESD, ±25V Common Mode Range,
20Mbps or 250kbps
LTM2881
Complete Isolated RS485 Transceiver
2500VRMS Isolation, Isolated DC Power (5V at Up to 200mA), 3.3V or 5V
Operation, No External Components Required
14
485fm
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/LTC485
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com/LTC485
LT 0217 REV M • PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 1994
工商网监
湘ICP备2023018690号
