OUT1 OUT2 GROUND GROUND OUT3 FAULT OUT4 ENABLE GROUND GROUND PROT

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OUT1 OUT2 GROUND GROUND OUT3 FAULT OUT4 ENABLE GROUND GROUND PROT

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A2557xLB
OUT1 OUT2 GROUND GROUND OUT3 FAULT OUT4 ENABLE GROUND GROUND
PROTECTED QUAD LOW-SIDE DRIVER WITH FAULT DETECTION SLEEP MODE
A2557xB, A2557xEB, A2557xLB have been specifically designed provide cost-effective solutions relay-driving applications with drive current channel. They also used driving incandescent lamps applications where turn-on time concern. Each four outputs will sink state. outputs have minimum breakdown voltage sustaining voltage low-power Sleep Mode activated with either ENABLE inputs low. this mode, supply current drops below Over-current protection each channel been designed into these devices activated nominal protects each output from short circuits with supply voltages When output experiences short circuit, output current limited current clamp. addition, foldback circuitry decreases current limit excessive voltage present across output assists keeping device within (safe operating area). exclusive-OR circuit compares input output state each driver. either short open load condition detected, single FAULT output turned (active low). Similar devices, operation available UDx2547B/EB. Continuous multiple overload conditions causing channel temperature reach approximately 165°C will result additional linear decrease output current affected driver. fault condition corrected, output stage will return normal saturated condition. first character part number suffix determines device operating temperature range. Suffix `S-' standard -20°C +85°C; suffix `E-' -40°C +85°C; suffix `K-' industrial temperature range -40°C +125°C. Package suffix `-B' devices 16-pin power DIPs; suffix `-EB' devices 28-lead power PLCCs; suffix `-LB' 16lead power wide-body SOICs surface-mount applications. packages batwing construction provide maximum package power dissipation.
Data Sheet 29317.16E
Dwg. PP-017-4
Note that A2557xB (DIP) A2557xLB (SOIC) electrically identical share common terminal number assignment.
ABSOLUTE MAXIMUM RATINGS
Output Voltage, Over-Current Protected Output Voltage, Output Current, FAULT Output Voltage, VFLT Logic Supply Voltage, Input Voltage, Package Power Dissipation, Graph Operating Temperature Range, Suffix `S-' -20°C +85°C Suffix `E-' -40°C +85°C Suffix `K-' -40°C +125°C Junction Temperature, +150°C* Storage Temperature Range, -55°C +150°C
*Outputs current limited approximately driver junction temperature limited higher current attempted.
FEATURES Output Current Channel Independent Over-Current Protection &Thermal Limiting Each Driver Output Voltage Output Protection Fault-Detection Circuitry Open Shorted Load Quiescent Current Sleep Mode Integral Output Flyback/Clamp Diodes TTL- CMOS-Compatible Inputs
Complete part number includes suffix identify operating temperature range (E-, package type (-B, -EB, -LB). Always order complete part number, e.g., A2557KLB
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
FUNCTIONAL BLOCK DIAGRAM
FAULT ENABLE SLEEP CONTROL
COMMON CONTROL FOUR DRIVERS
OUTN
THERMAL LIMIT CURRENT LIMIT
Dwg. FP-007-2
A2557xEB
CONNECTION
ENABLE
ALLOWABLE PACKAGE POWER DISSIPATION WATTS
OUT2
OUT1
SUFFIX 'EB', 36°C/W
6°C/W
GROUND GROUND GROUND GROUND
SUFFIX 'B', 43°C/W
SUFFIX 'LB', 63°C/W
TEMPERATURE
CONNECTION
FAULT
SUPPLY
Dwg. GP-004-2A
Dwg. PP-019-2
Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright 1998, 2000, Allegro MicroSystems, Inc.
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
ELECTRICAL CHARACTERISTICS over operating temperature range, 4.75 5.25
Characteristic
Output Leakage Current*
Symbol
ICEX
Test Conditions
Min.
Limits Typ. Max.
<1.0 <1.0 0.075
Units
Output Sustaining Voltage Output Saturation Voltage
VO(SUS) VO(SAT)
Open
Over-Current Limit Input Voltage
PulseTest, ENABLE ENABLE ENABLE, ENABLE, VFLT VFLT
Input Current
Fault Output Leakage Current
IFLT
Fault Output Current Fault Output Saturation Voltage Clamp Diode Forward Voltage
IFLT VFLT(SAT)
VFLT Driver Output Open, IFLT
Clamp Diode Leakage Current Turn-On Delay
tPHL
From Sleep,
Turn-Off Delay
tPLH
Total Supply Current
Outputs Output Outputs Three Outputs Outputs
Thermal Limit
Typical Data +25°C design information only. Negative current defined coming (sourcing) specified terminal. used here, -100 defined greater than (absolute magnitude convention) minimum 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
+25°C
OUTPUT CURRENT LIMIT MILLIAMPERES
Dwg. GP-064
OUTPUT SATURATION VOLTAGE VOLTS
Dwg. GP-065
OUTPUT CURRENT MILLIAMPERES
OUTPUT VOLTAGE VOLTS
SWITCHING (FROM SLEEP)
TURN-OFF DELAY MICROSECONDS
TURN-ON DELAY MICROSECONDS
+25°C
+25°C
ENABLE SWITCHING
SWITCHING (AWAKE)
Dwg. GP-066
Dwg. GP-066-1
OUTPUT CURRENT MILLIAMPERES
OUTPUT CURRENT MILLIAMPERES
Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
CIRCUIT DESCRIPTION APPLICATION
A2557 low-current quad power drivers provide same protected output driver function (and compatible with) UDx2543/49/59 devices, combined with fault diagnostic scheme similar UDx2547, plus automatic low-current Sleep-Mode function. These devices monitor their outputs fault (open shorted) conditions. each channel input output levels compared. these different from expected levels then fault condition flagged pulling common FAULT output low. Status Normal Load Sleep Mode Over-Current Short Supply Open Load Short Ground ENABLE OUTN FAULT power dissipation output device increases local junction temperature above 165°C (nominal), limit power dissipation (and hence local junction temperature). each channel thermal limit circuitry this provides some independence between output channels, i.e., channel operating thermally reduced current limit, while others provide full drive capability. function output voltage. Full current limit (nominal) available approximately above this limit reduced linearly about This helps improve immediately reducing peak power pulse into shorted load high logic ENABLE input causes outputs switched regardless state terminals. addition, device into quiescent current `sleep' mode, reducing below ENABLE taken high inputs high, circuit will `auto-wake-up'. However, device enabled, inputs stay low, then circuit remains `sleep' mode. outputs have internal flyback diodes, with commoncathode connection terminal. Incandescent lamp driver High incandescent lamp turn-on (in-rush currents) contribute poor lamp reliability destroy semiconductor lamp drivers. When incandescent lamp initially turned cold filament minimum resistance would normally allow in-rush current. Warming (parallel) current-limiting (series) resistors protect both driver lamp significant power either when lamp when lamp respectively. Lamps with steady-state current ratings driven without need warming current-limiting resistors, lamp turn-on time concern (10s ms). With these drivers, during turn-on, high in-rush current sensed internal sense resistor, drive current output stage reduced, output operates linear mode with load current limited approximately During lamp warmup, filament resistance increases maximum value, output driver goes into saturation applies maximum rated voltage lamp.
Thermal Fault Linear drive, current limited.
FAULT output operational only ENABLE high. output state detected monitoring OUTn terminal using comparator whose threshold typically order detect open-circuit outputs, current sink pulls output below comparator threshold. ensure correct fault operation, minimum load approximately required. fault function disabled when `sleep' mode, i.e., FAULT goes high output sinks turned off. FAULT output switched current sink typically Each channel consists TTL/CMOS-compatible logic input gated with common ENABLE input. logic high input will provide drive turn output switch. Each output current-limit circuit that limits output current detecting voltage drop across low-value internal resistor emitter output switch. this drop reaches threshold, then base drive output switch reduced maintain constant current output. keep device within safe operating area (SOA) this output current limit further reduced
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2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
CIRCUIT DESCRIPTION APPLICATION (continued)
Fault diagnostics
NORMAL LAMP IN-RUSH CURRENT
SCALE
LAMP CURRENT
pull-up resistor current source required FAULT output. This connected whatever supply level following circuitry requires (within specification constraints). supply (i.e., Vcc) greater should used. fault diagnostic function indicate when output state different from input state channel, FAULT output waveform will obviously produce pulse waveform following combined duty-cycle channels showing fault condition. There therefore basic approaches using function application: interrupt controller-based system. system microcontroller then FAULT causes interrupt, which then initiates diagnostic sequence find culprit channel. This sequence usually consists cycling through each channel time, while monitoring FAULT output. then easy determine which channel faulty output failing (i.e., short supply, opencircuit short ground). system then take whatever action required, could continue with operation remaining `good' channels while disabling signals faulty channel. simple `common' fault indication. there controller system then FAULT output give indication (via lamp LED, etc.) fault condition which might anywhere four channels. Because FAULT output dependent states input output (four possibilities) will only indicate them, duty cycle FAULT output will reflect duty cycle faulty channel's input inverse, depending upon fault type). typical applications (50% duty cycles) simple solution make pull-up current FAULT output much less than pull-down current µA), capacitor give time constant longer than period operation. typical values, device will produce continuous output level. Component values will need adjusted cope with different conditions.
THERMAL GRADIENT SENSING CURRENT LIMIT ITRIP
TIME
Dwg. WP-008
Inductive load driver Bifilar (unipolar) stepper motors (and other inductive loads) driven directly. internal diodes prevent damage output transistors suppressing high-voltage spikes that occur when turning inductive load. rapid current decay (fast turn-off speeds), Zener diodes will raise flyback voltage improve performance. However, peak voltage must exceed specified minimum sustaining voltage (VSUPPLY VO(SUS)). Over-current conditions event shorted load, stalled motor, load current will attempt increase. described above, drive current affected output stage linearly reduced, causing output linear (limiting load current about mA). junction temperature output stage increases, thermal-shutdown circuit will shut affected output. fault condition corrected, output driver will return normal saturated condition.
Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
CIRCUIT DESCRIPTION APPLICATION (continued)
SCALE
FAULT
(SHORTED LOAD)
WITH OUTPUT CAPACITOR
FAULT
(OPEN LOAD)
Dwg. WP-035
OUTPUT CURRENT
SHORT CIRCUIT
NORMAL LOAD CURRENT LIMIT SUPPLY)
Under some conditions possible spurious glitches FAULT output load turn-on turn-off transitions: Light load turn-off. Under light loading conditions turn-off delay (see characteristics above) output stage increases result spurious fault output (the duration being proportional turn-off delay). difficult define this over operating conditions, particular application would sensitive this type glitch, then generally recommended include small (about 0.01 smoothing/storage capacitor FAULT output. Incandescent lamp turn-on. described above, driving incandescent filament results driver operating current limit period after turn-on. During this period "fault" condition will indicated (over current). discussed above this period avoid this indication, capacitor FAULT output would need increased provide appropriate time constant. Alternatively, microcontroller-based system, code could written ignore FAULT condition appropriate period after lamp turn Correct FAULT operation cannot guaranteed with unconnected output unused outputs should turned unused outputs should pulled high >2.5 and/or associated inputs tied low.
CURRENT LIMIT SUPPLY)
TIME
Dwg. WP-013-1
Thermal considerations Device power dissipation calculated (VO1 duty cycle1) (VO4 duty cycle4) (VCC ICC) Note also modulated duty cycle, this reasonable approximation most purposes. This then compared against permitted package power dissipation, using: Permitted (150 TA)/RJA where given 28-lead PLCC (part number suffix `-EB') 36°C/W 16-pin PDIP (part number suffix `-B') 43°C/W 16-lead SOIC (part number suffix `-LB') 60°C/W thermal resistance from junction power (RJT) about 6°C/W three package types, therefore power dissipation improved adding area printed wiring board copper (typically square centimetres) connected power-tab GROUND terminals device.
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2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
A2557EB, A2557KB, A2557SB
Dimensions Inches (controlling dimensions)
0.020 0.008
NOTE
0.430 0.280 0.240
0.300
0.070 0.045
0.100 0.775 0.735
0.005
0.210
0.015
0.150 0.115 0.022 0.014
Dwg. MA-001-17A
Dimensions Millimeters (for reference only)
NOTE
0.508 0.204
10.92 7.11 6.10
7.62
1.77 1.15
2.54 19.68 18.67
0.13
5.33
0.39
3.81 2.93 0.558 0.356
Dwg. MA-001-17A
NOTES:1.
Exact body lead configuration vendor's option within limits shown. Lead spacing tolerance non-cumulative Lead thickness measured seating plane below. Webbed lead frame. Leads internally piece.
Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
A2557ELB, A2557KLB, A2557SLB
Dimensions Inches (for reference only)
0.0125 0.0091
0.2992 0.2914
0.419 0.394
0.050 0.016 0.020 0.013
0.4133 0.3977
0.050
0.0926 0.1043 0.0040 MIN.
Dwg. MA-008-17A
Dimensions Millimeters (controlling dimensions)
0.32 0.23
7.60 7.40
10.65 10.00
1.27 0.40 0.51 0.33
10.50 10.10
1.27
2.65 2.35 0.10 MIN.
Dwg. MA-008-17A
NOTES:1.
Exact body lead configuration vendor's option within limits shown. Lead spacing tolerance non-cumulative Lead thickness measured seating plane below. Webbed lead frame. Leads internally piece.
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2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
A2557EEB, A2557KEB, A2557SEB
Dimensions Inches (controlling dimensions)
0.013 0.021 0.219 0.191
0.050
0.026 0.032 0.456 0.450 0.495 0.485
INDEX AREA
0.219 0.191
0.020
0.165 0.180
0.456 0.450 0.495 0.485
Dwg. MA-005-28A
Dimensions Millimeters (for reference only)
0.331 0.533 5.56 4.85
1.27
0.812 0.661 11.58 11.43 12.57 12.32
INDEX AREA
5.56 4.85
0.51
4.57 4.20
11.582 11.430 12.57 12.32
Dwg. MA-005-28A
NOTES:1. Exact body lead configuration vendor's option within limits shown. Lead spacing tolerance non-cumulative Webbed lead frame. Leads through through internally piece.
Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
products described here manufactured under more U.S. patents U.S. patents pending. Allegro MicroSystems, Inc. reserves right make, from time time, such departures from detail specifications required permit improvements performance, reliability, manufacturability products. Before placing order, user cautioned verify that information being relied upon current. Allegro products authorized critical components life-support devices systems without express written approval. information included herein believed accurate reliable. However, Allegro MicroSystems, Inc. assumes responsibility use; infringement patents other rights third parties which result from use.
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2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
POWER SINK DRIVERS
ORDER OUTPUT CURRENT, OUTPUT VOLTAGE, NUMBER DRIVERS
Output Ratings
Serial Input
Latched Drivers
Features Diode Clamp
Outputs
Internal Protection
Part Number
constant current 6275 constant current 6276 saturated 2595 5833 saturated 5832 addressable decoder/driver DMOS 6B259 DMOS 6B273 DMOS 6B595 addressable decoder/driver DMOS 6259 DMOS 6273 DMOS 6595 7003 Hall sensor/driver 5140 2003 2803 saturated 2596 saturated 2557 2023 2823 5800 2004 2804 5801 5821 5841 addressable decoder/driver DMOS 6A259 DMOS 6A595 5822 5842 2024 2824 dual 14-line decoder/driver 6817 saturated 2547 saturated 2549 saturated 2543 2559 saturated 2597 Hall sensor/driver saturated 3625 Hall sensor/driver saturated 3626 1000 stepper motor controller/driver 7024 7029 1200 microstepping controller/driver 7042 1250 stepper motor translator/driver 5804 2064 2068 1500 2065 2069 1800 2544 2540 3000 stepper motor controller/driver 7026 microstepping controller/driver 7044 4000 2878 2879 Current maximum specified test condition, voltage maximum rating. specification sustaining voltage limits over-current protection voltage limits. Complete part number includes additional characters indicate operating temperature range package style.
Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000

OUT1 OUT2 GROUND GROUND OUT3 FAULT OUT4 ENABLE GROUND GROUND PROT

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