GROUND GROUND FAULT ENABLE GROUND GROUND PROTECTED QUAD LOW-SIDE

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GROUND GROUND FAULT ENABLE GROUND GROUND PROTECTED QUAD LOW-SIDE

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A2557xLB (SOIC)
GROUND GROUND FAULT 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). 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. packages offer fused leads enhanced thermal dissipation. Package 16-pin power with exposed tabs, 28-lead power PLCCs, 16-lead power wide-body SOICs surface-mount applications. lead (Pb) free versions have 100% matte leadframe plating.
Data Sheet 29317.16H
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
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
Selection Guide Part Number Pb-free Package Ambient Temperature (°C)
A2557SB A2557SB-T A2557SEB A2557SEB-T A2557SLB A2557SLB-T A2557EB A2557EB-T A2557EEB A2557EEB-T A2557ELB A2557ELB-T A2557KB A2557KB-T A2557KEB A2557KEB-T A2557KLB A2557KLB-T
16-pin DIP,exposed tabs 16-pin DIP,exposed tabs 28-lead PLCC 28-lead PLCC 16-lead SOIC 16-lead SOIC 16-pin DIP,exposed tabs 16-pin DIP,exposed tabs 28-lead PLCC 28-lead PLCC 16-lead SOIC 16-lead SOIC 16-pin DIP,exposed tabs 16-pin DIP,exposed tabs 28-lead PLCC 28-lead PLCC 16-lead SOIC 16-lead SOIC
Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
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 (PLCC)
CONNECTION ENABLE
ALLOWABLE PACKAGE POWER DISSIPATION WATTS
OUT2
OUT1
GROUND GROUND GROUND GROUND
SUFFIX 'EB',
6°C/W 36°C/W
SUFFIX 'B',
43°C/W
SUFFIX 'LB', 90°C/W
CONNECTION
FAULT
SUPPLY
TEMPERATURE
Dwg. PP-019-2
Dwg. GP-004-2B
Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 Copyright 1998, 2006 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* Output Sustaining Voltage Output Saturation Voltage Over-Current Limit Input Voltage Input Current Fault Output Leakage Current Fault Output Current Fault Output Saturation Voltage Clamp Diode Forward Voltage Clamp Diode Leakage Current Turn-On Delay
Symbol
ICEX VO(SUS) VO(SAT) IFLT IFLT VFLT(SAT) tPHL
Test Conditions
Open PulseTest, ENABLE ENABLE ENABLE, ENABLE, VFLT VFLT VFLT Driver Output Open, IFLT From Sleep,
Min.
Limits Typ. Max.
<1.0 <1.0 0.075
Units
Turn-Off Delay Total Supply Current
tPLH
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
OUTPUT CURRENT LIMIT MILLIAMPERES
OUTPUT SATURATION VOLTAGE VOLTS
+25°C
Dwg. GP-064
Dwg. GP-065
OUTPUT CURRENT MILLIAMPERES
OUTPUT VOLTAGE VOLTS
+25°C
TURN-OFF DELAY MICROSECONDS
TURN-ON DELAY MICROSECONDS
SWITCHING (FROM SLEEP)
+25°C
ENABLE SWITCHING
SWITCHING (AWAKE)
Dwg. GP-066
OUTPUT CURRENT MILLIAMPERES
Dwg. GP-066-1
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 protected output driver functions, combined with fault diagnostic scheme, 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
Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
CIRCUIT DESCRIPTION APPLICATION (continued)
Fault diagnostics
NORMAL LAMP IN-RUSH CURRENT
SCALE
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.
LAMP CURRENT
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
WITH OUTPUT CAPACITOR
FAULT
OUTPUT CURRENT
(SHORTED LOAD)
FAULT
(OPEN LOAD)
Dwg. WP-035
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') 90°C/W measured typical two-sided PCB. Additional information available Allegro site.
www.allegromicro.com
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
Package, 16-pin
with internally fused pins external thermal tabs
Preliminary dimensions, reference only Dimensions inches Metric dimensions (mm) brackets, reference only (reference JEDEC MS-001 Dimensions exclusive mold flash, gate burrs, dambar protrusions Exact case lead configuration supplier discretion within limits shown Terminal mark area
.775 19.69 .735 18.67
.014 0.36 .008 0.20
.280 7.11 .240 6.10
.300 .7.62
.430 10.92
.195 4.95 .115 2.92 .015 0.38 .100 .2.54 .022 .056 .014 .036 .010 [0.25] .150 3.81 .115 2.92
.210 5.33
SEATING PLANE
.005 0.13 .070 1.78 .045 1.14
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2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
Package, 28-pin PLCC
with internally fused pins through through
.495 12.57 .485 12.32 .007 [0.18]
.456 11.58 .450 11.43 .007 [0.18] .002 [0.05]
.456 11.58 .450 11.43 .007 [0.18] .002 [0.05]
.020 0.51
.219 5.56 .191 4.85
.219 5.56 .191 4.85 .495 12.57 .485 12.32 .007 [0.18] .020 0.51 .120 3.05 .090 2.29 .032 0.81 .026 0.66 .007 [0.18] .004 [0.10] .021 0.53 .013 0.33 .007 [0.18] .219 5.56 .191 4.85 Preliminary dimensions, reference only (reference JEDEC MS-018 Dimensions inches Millimeters (mm) brackets, reference only Dimensions exclusive mold flash, gate burrs, dambar protrusions Exact case lead configuration supplier discretion within limits shown Terminal mark area .219 5.56 .191 4.85 .180 4.57 .165 4.19
SEATING PLANE
.050 1.27
Northeast Cutoff, 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000
2557 PROTECTED QUAD DRIVER WITH FAULT DETECTION SLEEP MODE
Package, 16-pin SOIC
with internally fused pins
10.63 .419 9.97 .393 0.25 [.010] 10.50 .614 10.10 .598 0.33 .013 0.20 .008
7.60 .299 7.40 .291 1.27 .050 0.40 .016
0.25 .010
0.10 [.004] 0.51 .020 0.31 .012 0.25 [.010] 1.27 .050
SEATING PLANE 2.65 .104 2.35 .093 0.30 .012 0.10 .004
SEATING PLANE GAUGE PLANE
Preliminary dimensions, reference only Dimensions millimeters U.S. Customary dimensions (in.) brackets, reference only (reference JEDEC MS-013 Dimensions exclusive mold flash, gate burrs, dambar protrusions Exact case lead configuration supplier discretion within limits shown Terminal mark area
www.allegromicro.com
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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GROUND GROUND FAULT ENABLE GROUND GROUND PROTECTED QUAD LOW-SIDE

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