LINER LTC488IN Quad rs485 line receiver Datasheet

LTC488/LTC489
Quad RS485 Line Receiver
FEATURES
DESCRIPTION
n
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 requirements of RS422.
n
n
n
n
n
n
n
n
Low Power: ICC = 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
n
n
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 common mode range.
The receiver has a fail-safe feature which guarantees a
high output state when the inputs are left open.
Low Power RS485/RS422 Receivers
Level Translator
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.
TYPICAL APPLICATION
EN EN
EN
2
DI
DRIVER
1/4 LTC486
120Ω
120Ω
1
EN
4
12
RECEIVER
1/4 LTC488
3
RO
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
4889 TA01
4889fb
1
LTC488/LTC489
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Supply Voltage (VCC) ................................................12V
Control Input Currents .......................... –25mA to 25mA
Control Input Voltages ..................–0.5V to (VCC + 0.5V)
Receiver Input Voltages ..........................................±14V
Receiver Output Voltages ..............–0.5V to (VCC + 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
LTC488
TOP VIEW
B1
1
R
TOP VIEW
16 VCC
B1 1
15 B4
A1 2
RO1 3
A1
2
RO1
3
14 A4
EN
4
13 RO4
RO2
5
12 EN
A2
6
B2
7
GND
8
R
R
A2 6
B2 7
11 RO3
R
R
10 A3
9
B3
SW PACKAGE
16-LEAD PLASTIC (WIDE) SO
TJMAX = 150°C, θJA = 90°C/W
N PACKAGE
16-LEAD PLASTIC DIP
TJMAX = 150°C, θJA = 70°C/W
LTC489
14 A4
12 EN
GND 8
B3
15 B4
13 RO4
RO2 5
10 A3
9
R
EN 4
11 RO3
R
16 VCC
R
LTC489
TOP VIEW
B1
1
TOP VIEW
16 VCC
R
B1 1
16 VCC
R
A1
2
15 B4
A1 2
RO1
3
14 A4
RO1 3
EN12
4
13 RO4
EN12 4
13 RO4
12 EN34
RO2 5
12 EN34
RO2
5
A2
6
B2
7
GND
8
R
R
R
11 RO3
A2 6
10 A3
B2 7
9
B3
N PACKAGE
16-LEAD PLASTIC DIP
TJMAX = 150°C, θJA = 70°C/W
GND 8
R
15 B4
14 A4
11 RO3
R
R
10 A3
9
B3
SW PACKAGE
16-LEAD PLASTIC (WIDE) SO
TJMAX = 150°C, θJA = 90°C/W
4889fb
2
LTC488/LTC489
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC488CN#PBF
LTC488CN#TRPBF
LTC488CN
16-Lead Plastic DIP
0°C to 70°C
LTC488CSW#PBF
LTC488CSW#TRPBF
LTC488CSW
16-Lead Plastic SO
0°C to 70°C
LTC488IN#PBF
LTC488IN#TRPBF
LTC488IN
16-Lead Plastic DIP
–40°C to 85°C
LTC488ISW#PBF
LTC488ISW#TRPBF
LTC488ISW
16-Lead Plastic SO
–40°C to 85°C
LTC489CN#PBF
LTC489CN#TRPBF
LTC489CN
16-Lead Plastic DIP
0°C to 70°C
LTC489CSW#PBF
LTC489CSW#TRPBF
LTC489CSW
16-Lead Plastic SO
0°C to 70°C
LTC489IN#PBF
LTC489IN#TRPBF
LTC489IN
16-Lead Plastic DIP
–40°C to 85°C
LTC489ISW#PBF
LTC489ISW#TRPBF
LTC489ISW
16-Lead Plastic SO
–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
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V (Notes 2, 3), unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
VINH
Input High Voltage
EN, EN, EN12, EN34
l
VINL
Input Low Voltage
EN, EN, EN12, EN34
l
TYP
MAX
UNITS
2.0
V
0.8
V
IIN1
Input Current
EN, EN, EN12, EN34
l
±2
μA
IIN2
Input Current (A, B)
VCC = 0V or 5.25V, VIN = 12V
VCC = 0V or 5.25V, VIN = – 7V
l
l
1.0
–0.8
mA
mA
VTH
Differential Input Threshold Voltage for Receiver
–7V ≤ VCM ≤ 12V
l
–0.2
0.2
V
3.5
ΔVTH
Receiver Input Hysteresis
VCM = 0V
VOH
Receiver Output High Voltage
IO = –4mA, VID = 0.2V
l
VOL
Receiver Output Low Voltage
IO = 4mA, VID = –0.2V
l
0.4
V
IOZR
Three-State Output Current at Receiver
VCC = Max 0.4V ≤ VO ≤ 2.4V
l
±1
μA
ICC
Supply Current
No Load, Digital Pins = GND or VCC
l
10
mA
RIN
Receiver Input Resistance
–7V ≤ VCM ≤ 12V, VCC = 0V
l
7
60
mV
V
7
12
kΩ
IOSR
Receiver Short-Circuit Current
0V ≤ VO ≤ VCC
l
85
mA
t PLH
Receiver Input to Output
CL = 15pF (Figures 1, 3)
l
12
28
55
ns
l
12
28
55
ns
tPHL
Receiver Input to Output
CL = 15pF (Figures 1, 3)
tSKD
| t PLH – tPHL |
Differential Receiver Skew
CL = 15pF (Figures 1, 3)
4
ns
The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C.
VCC = 5V ± 5% (Notes 2, 3), unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
TYP
MAX
t ZL
Receiver Enable to Output Low
CL = 15pF (Figures 2, 4) S1 Closed
l
MIN
30
60
UNITS
ns
tZH
Receiver Enable to Output High
CL = 15pF (Figures 2, 4) S2 Closed
l
30
60
ns
tLZ
Receiver Disable from Low
CL = 15pF (Figures 2, 4) S1 Closed
l
30
60
ns
CL = 15pF (Figures 2, 4) S2 Closed
l
30
60
ns
t HZ
Receiver Disable from High
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 VCC = 5V and TA = 25°C.
4889fb
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LTC488/LTC489
TYPICAL PERFORMANCE CHARACTERISTICS
Receiver Output Low Voltage vs
Temperature at I = 8mA
Receiver Output High Voltage vs
Temperature at I = 8mA
–18
0.8
4.6
–16
0.7
4.4
–14
0.6
0.5
0.4
0.3
4.2
4.0
3.8
3.6
0.2
3.4
0.1
3.2
0
–50
–25
0
75
25
50
TEMPERATURE (°C)
100
125
OUTPUT CURRENT (mA)
4.8
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
0.9
Receiver Output High Voltage vs
Output Current at TA = 25°C
–12
–10
–8
–6
–4
–2
3.0
–50
–25
0
75
50
25
TEMPERATURE (°C)
100
4889 G01
125
0
5
4
3
OUTPUT VOLTAGE (V)
4889 G02
Receiver Output Low Voltage vs
Output Current at TA = 25°C
2
4889 G03
TTL Input Threshold vs
Temperature
36
1.63
INPUT THRESHOLD VOLTAGE (V)
OUTPUT CURRENT (mA)
32
28
24
20
16
12
8
1.61
1.59
1.57
4
1.55
–50
0
0.5
0
1.5
1.0
OUTPUT VOLTAGE (V)
2.0
–25
0
75
25
50
TEMPERATURE (°C)
Receiver | tPLH – tPHL| vs
Temperature
Supply Current vs Temperature
7.0
SUPPLY CURRENT (mA)
5
4
TIME (ns)
125
8889 G05
4889 G04
3
2
1
–50
100
–25
0
75
25
50
TEMPERATURE (°C)
100
125
4889 G06
6.6
6.2
5.8
5.4
–50
–25
0
75
25
50
TEMPERATURE (°C)
100
125
4889 G07
4889fb
4
LTC488/LTC489
PIN FUNCTIONS
B 1 (Pin 1): Receiver 1 Input.
GND (Pin 8): Ground Connection.
A1 (Pin 2): Receiver 1 Input.
B3 (Pin 9): Receiver 3 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.
A3 (Pin 10): Receiver 3 Input.
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.
RO3 (Pin 11): Receiver 3 Output. Refer to RO1.
EN (Pin 12) LTC488: Receiver Output Disabled. See Function 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.
RO2 (Pin 5): Receiver 2 Output. Refer to RO1.
A4 (Pin 14): Receiver 4 Input.
A2 (Pin 6): Receiver 2 Input.
B4 (Pin 15): Receiver 4 Input.
B2 (Pin 7): Receiver 2 Input.
VCC (Pin 16): Positive Supply; 4.75V ≤ VCC ≤ 5.25V.
FUNCTION TABLES
LTC488
LTC489
DIFFERENTIAL
ENABLES
OUTPUT
DIFFERENTIAL
ENABLES
OUTPUT
A–B
EN
EN
RO
A–B
EN12 or EN34
RO
VID ≥ 0.2V
H
X
X
L
H
H
VID ≥ 0.2V
H
H
–0.2V < VID < 0.2V
H
?
–0.2V < VID < 0.2V
H
X
X
L
?
?
VID ≤ 0.2V
H
L
VID ≤ 0.2V
H
X
X
L
L
L
X
L
Z
X
L
H
Z
H: High Level
L: Low Level
X: Irrelevant
?: Indeterminate
Z: High Impedance (Off)
4889fb
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LTC488/LTC489
TEST CIRCUITS
100pF
A
D
DRIVER
RO
RECEIVER
54Ω
CL
B
100pF
4889 F01
Figure 1. Receiver Timing Test Circuit
Note: The input pulse is supplied by a generator having the following characteristics:
f = 1MHz, Duty Cycle = 50%, tr < 10ns, tf ≤ 10ns, ZOUT = 50Ω
S1
RECEIVER
OUTPUT
1k
VCC
CL
1k
S2
4889 F02
Figure 2. Receiver Enable and Disable Timing Test Circuit
SWITCHING TIME WAVEFORMS
INPUT
VOD2
INPUT
A, B
f = 1MHz; tr ≤ 10ns; tf ≤ 10ns
0V
0V
–VOD2
tPHL
tPLH
VOH
RO
1.5V
1.5V
VOL
4889 F03
Figure 3. Receiver Propagation Delays
EN OR
EN12
3V
f = 1MHz; tr ≤ 10ns; tf ≤ 10ns
1.5V
1.5V
0V
tZL
tLZ
5V
RO
1.5V
VOL
OUTPUT NORMALLY LOW
tZH
VOH
RO
0.5V
tHZ
OUTPUT NORMALLY HIGH
0.5V
1.5V
0V
4889 F04
Figure 4. Receiver Enable and Disable Times
4889fb
6
LTC488/LTC489
APPLICATIONS INFORMATION
Typical Application
Cables and Data Rate
A typical connection of the LTC488/LTC489 is shown in
Figure 5. Two twisted-pair wires connect up to 32 driver/
receiver pairs for half-duplex data transmission. There are
no restrictions on where the chips are connected to the
wires, and it isn’t necessary to have the chips connected
at the ends. However, the wires must be terminated only
at the ends with a resistor equal to their characteristic
impedance, typically 120Ω. The input impedance of a
receiver is typically 20k to GND, or 0.5 unit RS485 load,
so in practice 50 to 60 transceivers can be connected to
the same wires. The optional shields around the twistedpair help reduce unwanted noise, and are connected to
GND at one end.
The transmission line of choice for RS485 applications is a
twisted-pair. There are coaxial cables (twinaxial) made for
this purpose that contain straight-pairs, but these are less
flexible, more bulky, and more costly than twisted-pairs.
Many cable manufacturers offer a broad range of 120Ω
cables designed for RS485 applications.
Losses in a transmission line are a complex combination
of DC conductor loss, AC losses (skin effect), leakage, and
AC losses in the dielectric. In good polyethylene cable such
as the Belden 9841, the conductor losses and dielectric
losses are of the same order of magnitude, leading to
relatively low overall loss (Figure 6).
When using low loss cables, Figure 7 can be used as a
guideline for choosing the maximum line length for a given
EN
SHIELD
SHIELD
4
DX
1
DX
1/4 LTC486
2
3
RX
1/4 LTC488 OR
1/4 LTC489
120Ω
120Ω
3
RX
1
12
1
EN
2
EN
12
DX
4
1/4 LTC486
1
DX
2
1/4 LTC488 OR
1/4 LTC489
RX
3
4889 F05
EN
3
RX
Figure 5. Typical Connection
10k
CABLE LENGTH (FT)
LOSS PER 100 FT (dB)
10
1
0.1
0.1
1
10
FREQUENCY (MHz)
100
4889 F06
Figure 6. Attenuation vs Frequency for Belden 9841
1k
100
10
10k
100k
1M
DATA RATE (bps)
2.5M
10M
4889 F07
Figure 7. Cable Length vs Data Rate
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7
LTC488/LTC489
APPLICATIONS INFORMATION
data rate. With lower quality PVC cables, the dielectric loss
factor can be 1000 times worse. PVC twisted-pairs have
terrible losses at high data rates (> 100kbps), and greatly
reduce the maximum cable length. At low data rates however, they are acceptable and much more economical.
Cable Termination
The proper termination of the cable is very important. If
the cable is not terminated with its characteristic impedance, distorted waveforms will result. In severe cases,
distorted (false) data and nulls will occur. A quick look
at the output of the driver will tell how well the cable is
terminated. It is best to look at a driver connected to the
end of the cable, since this eliminates the possibility of
getting reflections from two directions. Simply look at the
driver output while transmitting square wave data. If the
cable is terminated properly, the waveform will look like
a square wave (Figure 8).
If the cable is loaded excessively (47Ω), the signal initially
sees the surge impedance of the cable and jumps to an
initial amplitude. The signal travels down the cable and is
reflected back out of phase because of the mistermination.
PROBE HERE
DX
DRIVER
Rt
RECEIVER
RX
Rt = 120Ω
When the reflected signal returns to the driver, the amplitude will be lowered. The width of the pedestal is equal to
twice the electrical length of the cable (about 1.5ns/foot).
If the cable is lightly loaded (470Ω), the signal reflects
in phase and increases the amplitude at the drive output.
An input frequency of 30kHz is adequate for tests out to
4000 ft. of cable.
AC Cable Termination
Cable termination resistors are necessary to prevent unwanted reflections, but they consume power. The typical
differential output voltage of the driver is 2V when the
cable is terminated with two 120Ω resistors, causing
33mA of DC current to flow in the cable when no data
is being sent. This DC current is about 60 times greater
than the supply current of the LTC488/LTC489. One way
to eliminate the unwanted current is by AC coupling the
termination resistors as shown in Figure 9.
The coupling capacitor must allow high frequency energy
to flow to the termination, but block DC and low frequencies. The dividing line between high and low frequency
depends on the length of the cable. The coupling capacitor must pass frequencies above the point where the line
represents an electrical one-tenth wavelength. The value
of the coupling capacitor should therefore be set at 16.3pF
per foot of cable length for 120Ω cables. With the coupling
capacitors in place, power is consumed only on the signal
edges, and not when the driver output is idling at a 1 or 0
state. A 100nF capacitor is adequate for lines up to 4000
feet in length. Be aware that the power savings start to
decrease once the data rate surpasses 1/(120Ω)(C).
Rt = 47Ω
120Ω
RECEIVER
RX
C
Rt = 470Ω
C = LINE LENGTH (FT)(16.3pF)
4889 F08
488/9 F09
Figure 9. AC-Coupled Termination
Figure 8. Termination Effects
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LTC488/LTC489
APPLICATIONS INFORMATION
Receiver Open-Circuit Fail-Safe
Some data encoding schemes require that the output of the
receiver maintains a known state (usually a logic 1) when
the data is finished transmitting and all drivers on the line
are forced in three-state. The receiver of the LTC488/LTC489
has a fail-safe feature which guarantees the output to be
in a logic 1 state when the receiver inputs are left floating
(open-circuit). When the input is terminated with 120Ω
and the receiver output must be forced to a known state,
the circuits of Figure 10 can be used.
5V
110Ω
130Ω
130Ω
RECEIVER
RX
RECEIVER
RX
110Ω
5V
1.5k
120Ω
The termination resistors are used to generate a DC bias
which forces the receiver output to a known state, in this
case a logic 0. The first method consumes about 208mW
and the second about 8mW. The lowest power solution is to
use an AC termination with a pullup resistor. Simply swap
the receiver inputs for data protocols ending in logic 1.
Fault Protection
All of LTC’s RS485 products are protected against ESD transients up to 2kV using the human body model (100pF, 1.5k).
However, some applications need more protection. The best
protection method is to connect a bidirectional TransZorb®
from each line side pin to ground (Figure 11).
A TransZorb is a silicon transient voltage suppressor that
has exceptional surge handling capabilities, fast response
time, and low series resistance. They are available from
General instruments, GSI, and come in a variety of breakdown voltages and prices. Be sure to pick a breakdown
voltage higher than the common mode voltage required
for your application (typically 12V). Also, don’t forget to
check how much the added parasitic capacitance will load
down the bus.
1.5k
Y
5V
120Ω
DRIVER
100k
Z
C
120Ω
RECEIVER
RX
4889 F11
Figure 11. ESD Protection with TransZorbs
4889 F10
Figure 10. Forcing “0” When All Drivers Are Off
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LTC488/LTC489
PACKAGE DESCRIPTION
N Package
16-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
.770*
(19.558)
MAX
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
.255 ± .015*
(6.477 ± 0.381)
.130 ± .005
(3.302 ± 0.127)
.300 – .325
(7.620 – 8.255)
.008 – .015
(0.203 – 0.381)
(
+.035
.325 –.015
+0.889
8.255
–0.381
NOTE:
1. DIMENSIONS ARE
)
.045 – .065
(1.143 – 1.651)
.020
(0.508)
MIN
.065
(1.651)
TYP
.120
(3.048)
MIN
.100
(2.54)
BSC
INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
.018 ± .003
(0.457 ± 0.076)
N16 1002
4889fb
10
LTC488/LTC489
PACKAGE DESCRIPTION
SW Package
16-Lead Plastic Small Outline (Wide .300 Inch)
(Reference LTC DWG # 05-08-1620)
.050 BSC .045 ±.005
.030 ±.005
TYP
.398 – .413
(10.109 – 10.490)
NOTE 4
16
N
15
14
13
12
11
10
9
N
.325 ±.005
.420
MIN
.394 – .419
(10.007 – 10.643)
NOTE 3
1
2
3
N/2
N/2
RECOMMENDED SOLDER PAD LAYOUT
1
.005
(0.127)
RAD MIN
.009 – .013
(0.229 – 0.330)
.291 – .299
(7.391 – 7.595)
NOTE 4
.010 – .029 × 45°
(0.254 – 0.737)
3
4
5
6
7
.093 – .104
(2.362 – 2.642)
8
.037 – .045
(0.940 – 1.143)
0° – 8° TYP
NOTE 3
.016 – .050
(0.406 – 1.270)
NOTE:
1. DIMENSIONS IN
2
.050
(1.270)
BSC
.004 – .012
(0.102 – 0.305)
.014 – .019
(0.356 – 0.482)
TYP
INCHES
(MILLIMETERS)
2. DRAWING NOT TO SCALE
3. PIN 1 IDENT, NOTCH ON TOP AND CAVITIES ON THE BOTTOM OF PACKAGES ARE THE MANUFACTURING OPTIONS.
THE PART MAY BE SUPPLIED WITH OR WITHOUT ANY OF THE OPTIONS
4. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
S16 (WIDE) 0502
4889fb
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
11
LTC488/LTC489
TYPICAL APPLICATION
RS232 Receiver
RS232
IN
5.6k
RECEIVER
1/4 LTC488 OR
1/4 LTC489
RX
4889 TA02
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
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Low Power, Half-Duplex
LTC490
Low Power RS485 Full-Duplex Transceiver
Full-Duplex in SO-8
LTC1480
3V, Ultralow Power RS485 Transceiver
1μA Shutdown Mode
LTC1481
3V, Ultralow Power RS485 Transceiver
Lowest Power on 5V Supply
LTC1483
Ultralow Power RS485 Low EMI Transceiver
Low EMI/Low Power with Shutdown
LTC1485
Fast RS485 Transceiver
10Mbps Operation
LTC1487
Ultralow Power RS485 with Low EMI and High Input Impedance
Up to 256 Nodes on a Bus
LTC1685
High Speed RS485 Transceiver
52Mbps, Pin Compatible with LTC485
LTC1686/LTC1687
High Speed RS485 Full-Duplex Transceiver
52Mbps, Pin Compatible LTC490/LTC491
4889fb
12 Linear Technology Corporation
LT 0309 REV B • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 1992