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2557
A2557xLB (SOIC)
OUT1 K OUT2 GROUND GROUND OUT3 FAULT OUT4 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 IN 1 IN2 ENABLE GROUND GROUND V CC IN 3 IN 4
PROTECTED QUAD LOW-SIDE DRIVER WITH FAULT DETECTION & SLEEP MODE
The A2557xB, A2557xEB, and A2557xLB have been specifically designed to provide cost-effective solutions to relay-driving applications with up to 300 mA drive current per channel. They may also be used for driving incandescent lamps in applications where turn-on time is not a concern. Each of the four outputs will sink 300 mA in the on state. The outputs have a minimum breakdown voltage of 60 V and a sustaining voltage of 40 V. A low-power Sleep Mode is activated with either ENABLE low or all inputs low. In this mode, the supply current drops to below 100 A. Over-current protection for each channel has been designed into these devices and is activated at a nominal 500 mA. It protects each output from short circuits with supply voltages up to 32 V. When an output experiences a short circuit, the output current is limited at the 500 mA current clamp. In addition, foldback circuitry decreases the current limit if an excessive voltage is present across the output and assists in keeping the device within its SOA (safe operating area). An exclusive-OR circuit compares the input and output state of each driver. If either a short or open load condition is detected, a single FAULT output is turned on (active low). Similar devices, for operation to 1.3 A, are available as the UDx2547B/EB. Continuous or multiple overload conditions causing the channel temperature to reach approximately 165C will result in an additional linear decrease in the output current of the affected driver. If the fault condition is corrected, the output stage will return to its normal saturated condition. The first character of the part number suffix determines the device operating temperature range. Suffix `S-' is the standard -20C to +85C; suffix `E-' is -40C to +85C; suffix `K-' is for the industrial temperature range of -40C to +125C. Package suffix `-B' devices are 16-pin power DIPs; suffix `-EB' devices are 28-lead power PLCCs; and suffix `-LB' are 16lead power wide-body SOICs for surface-mount applications. All packages are of batwing construction to provide for maximum package power dissipation.
Data Sheet 29317.16F
Dwg. PP-017-4
Note that the A2557xB (DIP) and the A2557xLB (SOIC) are electrically identical and share a common terminal number assignment.
ABSOLUTE MAXIMUM RATINGS
Output Voltage, VO .............................. 60 V Over-Current Protected Output Voltage, VO ..................................................... 32 V Output Current, IO ......................... 500 mA* FAULT Output Voltage, VFLT ............. 60 V Logic Supply Voltage, VCC ................. 7.0 V Input Voltage, VI or VOE ..................... 7.0 V Package Power Dissipation, PD ........................................... See Graph Operating Temperature Range, TA Suffix `S-' ...................... -20C to +85C Suffix `E-' ...................... -40C to +85C Suffix `K-' ................... -40C to +125C Junction Temperature, TJ ............................................... +150C* Storage Temperature Range, TS ................................. -55C to +150C
*Outputs are current limited at approximately 500 mA per driver and junction temperature limited if higher current is attempted.
FEATURES s 300 mA Output Current per Channel s Independent Over-Current Protection &Thermal Limiting for Each Driver s Output Voltage to 60 V s Output SOA Protection s Fault-Detection Circuitry for Open or Shorted Load s Low Quiescent Current Sleep Mode s Integral Output Flyback/Clamp Diodes s TTL- and 5 V CMOS-Compatible Inputs
Complete part number includes a suffix to identify operating temperature range (E-, K-, or S-) and package type (-B, -EB, or -LB). Always order by complete part number, e.g., A2557KLB .
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION & SLEEP MODE
FUNCTIONAL BLOCK DIAGRAM
FAULT ENABLE SLEEP CONTROL
60 A K
COMMON CONTROL ONE OF FOUR DRIVERS V CC
- +
2.5 V OUTN
IN N THERMAL LIMIT CURRENT LIMIT
30 A
<<1
Dwg. FP-007-2
A2557xEB (PLCC)
NO CONNECTION
ALLOWABLE PACKAGE POWER DISSIPATION IN WATTS
IN 1
K
IN 2
ENABLE
5
OUT2
OUT1
28
27
26
3
1
4
SUFFIX 'EB', R
JA
R JT = 6C/W
4
2
NC GROUND 5 6 7 8 9 10 GROUND 11 NC VCC 25 24 23 22 21 20 19 GROUND GROUND
= 36C/W
3
SUFFIX 'B', R JA = 43C/W
2
1
SUFFIX 'LB', R JA = 90C/W
15
12
13
14
16
17
18
0 25 50 75 100 TEMPERATURE IN C 125 150
NO CONNECTION
FAULT
OUT 4
OUT 3
IN 4
IN 3
SUPPLY
Dwg. GP-004-2B
Dwg. PP-019-2
2
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright (c) 1998, 2002 Allegro MicroSystems, Inc.
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION & SLEEP MODE
ELECTRICAL CHARACTERISTICS over operating temperature range, VCC = 4.75 V to 5.25 V
Characteristic
Output Leakage Current*
Symbol
ICEX
Test Conditions
VO = 60 V, VI = 0.8 V, VOE = 2.0 V VO = 60 V, VI = 2.0 V, VOE = 0.8 V
Min.
-- -- 40 -- -- -- 2.0 -- -- -- -- -- 40 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
Limits Typ. Max.
30 <1.0 -- 65 180 500 -- -- -- -- 4.0 <1.0 60 0.1 1.2 1.5 -- 0.6 3.0 1.3 2.0 1.4 0.075 12 18 24 30 165 100 100 -- 200 300 -- -- 0.8 10 -10 15 2.0 80 0.4 1.7 2.1 50 10 -- 10 10 10 0.1 20 30 40 50 --
Units
A A V mV mV mA V V A A A A A V V V A s s s s s mA mA mA mA mA C
Output Sustaining Voltage Output Saturation Voltage
VO(SUS) VO(SAT)
IO = 100 mA, VI = VOE = 0.8 V, VCC = Open IO = 100 mA IO = 300 mA
Over-Current Limit Input Voltage
IOM VIH VIL
5 ms PulseTest, VO = 5.0 V INn or ENABLE INn or ENABLE INn or ENABLE, VIH = 2.0 V INn or ENABLE, VIL = 0.8 V VFLT = 60 V VFLT = 5 V
Input Current
IIH IIL
Fault Output Leakage Current
IFLT
Fault Output Current Fault Output Saturation Voltage Clamp Diode Forward Voltage
IFLT VFLT(SAT) VF
VFLT = 5 V, Driver Output Open, VI = 0.8 V, VOE = 2.0 V IFLT = 30 A IF = 500 mA IF = 750 mA
Clamp Diode Leakage Current Turn-On Delay
IR tPHL
VR = 60 V IO = 300 mA, 50% VI to 50% VO From Sleep, IO = 300 mA, 50% VI to 50% VO IO = 300 mA, 50% VOE to 50% VO
Turn-Off Delay
tPLH
IO = 300 mA, 50% VI to 50% VO IO = 300 mA, 50% VOE to 50% VO
Total Supply Current
ICC
All Outputs Off Any One Output On Two Outputs On Three Outputs On All Outputs On
Thermal Limit
TJ
Typical Data is at TA = +25C and VCC = 5 V and is for design information only. Negative current is defined as coming out of (sourcing) the specified terminal. As used here, -100 is defined as greater than +10 (absolute magnitude convention) and the minimum is implicitly zero. * Measurement includes output fault-sensing pull-down current.
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2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION & SLEEP MODE
TYPICAL OPERATING CHARACTERISTICS
600 TA = +25C VCC = 5 V 500
0.2
TA
=
12
C 5
5C
TA
=2
OUTPUT CURRENT LIMIT IN MILLIAMPERES
400
Dwg. GP-064
OUTPUT SATURATION VOLTAGE IN VOLTS
0.3
VCC = 5 V
TA
0.1
=-
40
C
400
300
0 0 100 200 300
0
10
20
30
40
Dwg. GP-065
OUTPUT CURRENT IN MILLIAMPERES
OUTPUT VOLTAGE IN VOLTS
6
IN SWITCHING (FROM SLEEP)
TURN-OFF DELAY IN MICROSECONDS
4
TURN-ON DELAY IN MICROSECONDS
TA = +25C VCC = 5 V
3
TA = +25C VCC = 5 V 2
IN S
WIT
CH
ING
ENABLE SWITCHING
2
ENA
BLE
SW
ITC
HIN
1
G
IN SWITCHING (AWAKE)
0 0 100 200 300 400
Dwg. GP-066
0 0 100 200 300 400
Dwg. GP-066-1
OUTPUT CURRENT IN MILLIAMPERES
OUTPUT CURRENT IN MILLIAMPERES
4
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION & SLEEP MODE
CIRCUIT DESCRIPTION AND APPLICATION
The A2557 low-current quad power drivers provide the same protected output driver function as (and are pin compatible with) the UDx2543/49/59 devices, combined with a fault diagnostic scheme similar to the UDx2547, plus an automatic low-current Sleep-Mode function. These devices monitor their outputs for fault (open or shorted) conditions. For each channel the input and output levels are compared. If these are different from the expected levels then a fault condition is flagged by pulling the common FAULT output low. Status Normal Load Sleep Mode Over-Current or Short to Supply Open Load or Short to Ground INN H L X All L H L ENABLE H H L X H H OUTN L H H H R L H FAULT H H H H L L L * if the power dissipation in the output device increases the local junction temperature above 165C (nominal), so as to limit the power dissipation (and hence the local junction temperature). As each channel has its own thermal limit circuitry this provides some independence between the output channels, i.e., one channel can be operating in thermally reduced current limit, while the others can provide full drive capability. * as a function of the output voltage. Full current limit of 500 mA (nominal) is available up to approximately VO = 8 V; above this the limit is reduced linearly to about 350 mA at VO = 32 V. This helps to improve SOA by immediately reducing the peak power pulse into a shorted load at high VO. A logic low at the ENABLE input causes all outputs to be switched off regardless of the state of the IN terminals. In addition, the device is put into a low quiescent current `sleep' mode, reducing ICC below 100 A. If ENABLE is taken high and any of the inputs go high, the circuit will `auto-wake-up'. However, if the device is enabled, but all inputs stay low, then the circuit remains in `sleep' mode. All outputs have internal flyback diodes, with a commoncathode connection at the K terminal. Incandescent lamp driver High incandescent lamp turn-on (in-rush currents) can contribute to poor lamp reliability and destroy semiconductor lamp drivers. When an incandescent lamp is initially turned on, the cold filament is at minimum resistance and would normally allow a 10x to 12x in-rush current. Warming (parallel) or current-limiting (series) resistors protect both driver and lamp but use significant power either when the lamp is off or when the lamp is on, respectively. Lamps with steady-state current ratings up to 300 mA can be driven without the need for warming or current-limiting resistors, if lamp turn-on time is not a concern (10s of ms). With these drivers, during turn-on, the high in-rush current is sensed by the internal sense resistor, drive current to the output stage is reduced, and the output operates in a linear mode with the load current limited to approximately 500 mA. During lamp warmup, the filament resistance increases to its maximum value, the output driver goes into saturation and applies maximum rated voltage to the lamp.
Thermal Fault H H R = Linear drive, current limited.
The FAULT output is operational only if ENABLE is high. The output state is detected by monitoring the OUTn terminal using a comparator whose threshold is typically 2.5 V. In order to detect open-circuit outputs, a 30 A current sink pulls the output below the comparator threshold. To ensure correct fault operation, a minimum load of approximately 1 mA is required. The fault function is disabled when in `sleep' mode, i.e., FAULT goes high and the 30 A output sinks are turned off. The FAULT output is a switched current sink of typically 60 A. Each channel consists of a TTL/CMOS-compatible logic input gated with a common ENABLE input. A logic high at the input will provide drive to turn on the output npn switch. Each output has a current-limit circuit that limits the output current by detecting the voltage drop across a low-value internal resistor in the emitter of the output switch. If this drop reaches a threshold, then the base drive to the output switch is reduced to maintain constant current in the output. To keep the device within its safe operating area (SOA) this output current limit is further reduced
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2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION & SLEEP MODE
CIRCUIT DESCRIPTION AND APPLICATION (continued)
Fault diagnostics
NORMAL LAMP IN-RUSH CURRENT
NOT TO SCALE
LAMP CURRENT
A pull-up resistor or current source is required on the FAULT output. This can be connected to whatever supply level the following circuitry requires (within the specification constraints). For a 5 V supply (i.e., Vcc) 150 k or greater should be used. As the fault diagnostic function is to indicate when the output state is different from the input state for any channel, the FAULT output waveform will obviously produce a pulse waveform following the combined duty-cycle of all channels showing a fault condition. There are therefore two basic approaches to using the function in an application: * As an interrupt in a controller-based system. If the system has a microcontroller then a FAULT low causes an interrupt, which then initiates a diagnostic sequence to find the culprit channel. This sequence usually consists of cycling through each channel one at a time, while monitoring the FAULT output. It is then easy to determine which channel has the faulty output and how it is failing (i.e., short to supply, opencircuit or short to ground). The system may then take whatever action is required, but could continue with operation of the remaining `good' channels while disabling signals to the faulty channel. * As a simple `common' fault indication. If there is no controller in the system then the FAULT output can be set to give an indication (via a lamp or LED, etc.) of a fault condition which might be anywhere on the four channels. Because the FAULT output is dependent on the states of the input and output (four possibilities) but will only indicate on two of them, the duty cycle at the FAULT output will reflect the duty cycle at the faulty channel's input (or its inverse, depending upon fault type). In typical applications (50% duty cycles) a simple solution is to make the pull-up current on the FAULT output much less than the pull-down current (60 A), and add a capacitor to give a time constant longer than the period of operation. For typical values, the device will produce a continuous dc output level. Component values will need to be adjusted to cope with different conditions.
THERMAL GRADIENT SENSING CURRENT LIMIT ITRIP
0
TIME
Dwg. WP-008
Inductive load driver Bifilar (unipolar) stepper motors (and other inductive loads) can be driven directly. The internal diodes prevent damage to the output transistors by suppressing the high-voltage spikes that occur when turning off an inductive load. For rapid current decay (fast turn-off speeds), the use of Zener diodes will raise the flyback voltage and improve performance. However, the peak voltage must not exceed the specified minimum sustaining voltage (VSUPPLY + VZ + VF < VO(SUS)). Over-current conditions In the event of a shorted load, or stalled motor, the load current will attempt to increase. As described above, the drive current to the affected output stage is linearly reduced, causing the output to go linear (limiting the load current to about 500 mA). As the junction temperature of the output stage increases, the thermal-shutdown circuit will shut off the affected output. If the fault condition is corrected, the output driver will return to its normal saturated condition.
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115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION & SLEEP MODE
CIRCUIT DESCRIPTION AND APPLICATION (continued)
IN
NOT TO SCALE
FAULT
(SHORTED LOAD)
WITH OUTPUT CAPACITOR
FAULT
(OPEN LOAD)
Dwg. WP-035
OUTPUT CURRENT
SHORT CIRCUIT
NORMAL LOAD CURRENT LIMIT (12 V SUPPLY)
Under some conditions it is possible to get spurious glitches on the FAULT output at load turn-on and turn-off transitions: * Light load turn-off. Under light loading conditions the turn-off delay (see characteristics above) of the output stage increases and may result in a spurious fault output of a few s (the duration being proportional to the turn-off delay). As it is difficult to define this over all operating conditions, if a particular application would be sensitive to this type of glitch, then it is generally recommended to include a small (about 0.01 F) smoothing/storage capacitor at the FAULT output. * Incandescent lamp turn-on. As described above, driving an incandescent filament results in the driver operating in current limit for a period after turn-on. During this period a "fault" condition will be indicated (over current). As discussed above this period can be 10s of ms. To avoid this indication, the capacitor on the FAULT output would need to be increased to provide an appropriate time constant. Alternatively, in a microcontroller-based system, the code could be written to ignore the FAULT condition for an appropriate period after lamp turn on. Correct FAULT operation cannot be guaranteed with an unconnected output -- unused outputs should not be turned on, or unused outputs should be pulled high to >2.5 V, and/or associated inputs tied low.
CURRENT LIMIT (24 V SUPPLY)
TIME
Dwg. WP-013-1
Thermal considerations Device power dissipation can be calculated as: PD = (VO1 x IO1 x duty cycle1) + ... + (VO4 x IO4 x duty cycle4) + (VCC x ICC) Note - ICC is also modulated by the duty cycle, but this is a reasonable approximation for most purposes. This can then be compared against the permitted package power dissipation, using: Permitted PD = (150 - TA)/RJA where RJA is given as: 28-lead PLCC (part number suffix `-EB') = 36C/W 16-pin PDIP (part number suffix `-B') = 43C/W 16-lead SOIC (part number suffix `-LB') = 90C/W RJA is measured on typical two-sided PCB with minimal copper ground area. The thermal resistance from junction to power tab (RJT) is about 6C/W for the three package types, therefore the power dissipation can be improved by 20% to 30% by adding an area of printed wiring board copper (typically 6 to 18 square centimetres) connected to the power-tab GROUND terminals of the device. See Application Note 29501.5, Improving Batwing Power Dissipation.
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2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION & SLEEP MODE
A2557EB, A2557KB, & A2557SB
Dimensions in Inches (controlling dimensions)
16
NOTE 4
9
0.020 0.008
0.430 0.280 0.240
MAX
0.300
BSC
1 0.070 0.045
0.100 0.775 0.735
BSC
8 0.005
MIN
0.210
MAX
0.015
MIN
0.150 0.115 0.022 0.014
Dwg. MA-001-17A in
Dimensions in Millimeters (for reference only)
16
NOTE 4
9
0.508 0.204
10.92 7.11 6.10
MAX
7.62
BSC
1 1.77 1.15
2.54 19.68 18.67
BSC
8 0.13
MIN
5.33
MAX
0.39
MIN
3.81 2.93 0.558 0.356
Dwg. MA-001-17A mm
NOTES:1. 2. 3. 4.
Exact body and lead configuration at vendor's option within limits shown. Lead spacing tolerance is non-cumulative Lead thickness is measured at seating plane or below. Webbed lead frame. Leads 4, 5, 12, and 13 are internally one piece.
8
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION & SLEEP MODE
A2557ELB, A2557KLB, & A2557SLB
Dimensions in Inches (for reference only)
16 9 0.0125 0.0091
0.2992 0.2914
0.419 0.394
0.050 0.016 0.020 0.013
1
2
3 0.4133 0.3977
0.050
BSC
0 TO 8
0.0926 0.1043 0.0040 MIN.
Dwg. MA-008-17A in
Dimensions in Millimeters (controlling dimensions)
16 9 0.32 0.23
7.60 7.40
10.65 10.00
1.27 0.40 0.51 0.33
1
2
3 10.50 10.10
1.27
BSC
0 TO 8
2.65 2.35 0.10 MIN.
Dwg. MA-008-17A mm
NOTES:1. 2. 3. 4.
Exact body and lead configuration at vendor's option within limits shown. Lead spacing tolerance is non-cumulative Lead thickness is measured at seating plane or below. Webbed lead frame. Leads 4, 5, 12, and 13 are internally one piece.
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2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION & SLEEP MODE
A2557EEB, A2557KEB, & A2557SEB
Dimensions in Inches (controlling dimensions)
18 12
0.013 0.021 0.219 0.191
19
11
0.026 0.032 0.456 0.450
BSC
INDEX AREA
0.050 0.219 0.191
0.495 0.485 25 5
26 0.020
MIN
28
1
4
0.165 0.180
0.456 0.450 0.495 0.485
Dwg. MA-005-28A in
Dimensions in Millimeters (for reference only)
18 12
0.331 0.533 5.56 4.85
19
11
1.27
BSC
0.812 0.661 11.58 11.43 12.57 12.32
INDEX AREA
5.56 4.85
25
5
26 0.51
MIN
28
1
4
4.57 4.20
11.582 11.430 12.57 12.32
Dwg. MA-005-28A mm
NOTES:1. Exact body and lead configuration at vendor's option within limits shown. 2. Lead spacing tolerance is non-cumulative 3. Webbed lead frame. Leads 5 through 11 and 19 through 25 are internally one piece.
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
10
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION & SLEEP MODE
The products described here are manufactured under one or more U.S. patents or U.S. patents pending. Allegro MicroSystems, Inc. reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the information being relied upon is current. Allegro products are not authorized for use as critical components in life-support devices or systems without express written approval. The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, Inc. assumes no responsibility for its use; nor for any infringement of patents or other rights of third parties which may result from its use.
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2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION & SLEEP MODE
POWER SINK DRIVERS
IN ORDER OF 1) OUTPUT CURRENT, 2) OUTPUT VOLTAGE, 3) NUMBER OF DRIVERS
Output Ratings * mA
75
V
#
Serial Input
Latched Drivers
Features Diode Clamp
Outputs
Internal Protection
Part Number
17 8 X X - constant current - 6275 17 16 X X - constant current - 6276 100 20 8 - - - saturated - 2595 30 32 X X - - - 5833 40 32 X X - saturated - 5832 50 8 addressable decoder/driver DMOS - 6B259 50 8 - X - DMOS - 6B273 50 8 X X - DMOS - 6B595 120 24 8 X X - constant current - 6277 250 50 8 addressable decoder/driver DMOS - 6259 50 8 - X - DMOS - 6273 50 8 X X - DMOS - 6595 50 8 - - X saturated - 2596 60 4 - - X saturated X 2557 350 50 4 - X X - - 5800 50 7 - - X - - 2003 50 7 - - X - - 2004 50 8 - - X - - 2803 50 8 - X X - - 5801 50 8 X X - - - 5821 50 8 X X X - - 5841 50 8 addressable decoder/driver DMOS - 6A259 50 8 X X - DMOS - 6A595 80 8 X X - - - 5822 80 8 X X X - - 5842 95 7 - - X - - 2023 95 7 - - X - - 2024 450 30 28 dual 4- to 14-line decoder/driver - - 6817 600 60 4 - - - saturated X 2547 60 4 - - X saturated X 2549 and 2559 700 60 4 - - X saturated X 2543 750 50 8 - - X saturated - 2597 1000 46 4 stepper motor controller/driver MOS - 7024 and 7029 1200 46 4 microstepping controller/driver MOS - 7042 1250 50 4 stepper motor translator/driver - X 5804 1800 50 4 - - X - - 2540 3000 46 4 stepper motor controller/driver MOS - 7026 46 4 microstepping controller/driver MOS - 7044 4000 50 4 - - X - - 2878 * Current is maximum specified test condition, voltage is maximum rating. See specification for sustaining voltage limits or over-current protection voltage limits. Complete part number includes additional characters to indicate operating temperature range and package style.
12
115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000

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