MAX4370ESA+-MAX4370ESA+T Fast Delivery |IC PHOENIX CO.,LIMITED

MAX4370ESA+T ,Current-Regulating Hot-Swap Controller with DualSpeed/BiLevel Fault ProtectionELECTRICAL CHARACTERISTICS(V = +2.7V to +13.2V, T = -40°C to +85°C, unless otherwise noted. Typical ..
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MAX4370ESA+-MAX4370ESA+T
Current-Regulating Hot-Swap Controller with DualSpeed/BiLevel Fault Protection
General Description
The MAX4370 is a circuit-breaker IC designed to offerprotection in hot-swap applications using Maxim’sDualSpeed/BiLevel™ detection. This controller,designed to reside either on the backplane or on theremovable card, is used to protect a system from start-up damage when a card or board is inserted into a rackwith the main system power supply turned on. Thecard’s discharged filter capacitors provide a lowimpedance that can momentarily cause the main powersupply to collapse. The MAX4370 prevents this start-upcondition by providing inrush current regulation duringa programmable start-up period, allowing the system tostabilize safely. In addition, two on-chip comparatorsprovide DualSpeed/BiLevel short-circuit protection andovercurrent protection during normal operation.
The MAX4370 provides protection for a +3V to +12Vsingle supply. An internal charge pump generates thecontrolled gate drive for an external N-channel MOS-FET power switch. The MAX4370 latches the switch offafter a fault condition until an external reset signalclears the device. Other features include a status pin toindicate a fault condition, an adjustable overcurrentresponse time, and a power-on reset comparator.
The MAX4370 is specified for the extended-industrialtemperature range (-40°C to +85°C) and is available inan 8-pin SO package.
Applications
Hot Board Insertion
Solid-State Circuit Breaker
FeatureDualSpeed/BiLevel Protection During Normal
OperationInrush Current Regulated at Start-UpResides Either on the Backplane or on the
Removable CardProgrammable Start-Up Period and Response
TimeAllows Safe Board Insertion and Removal from
Live BackplaneProtection for +3V to +12V Single SuppliesLatched Off After Fault ConditionStatus Output PinInternal Charge Pump Generates Gate Drive for
External N-Channel MOSFET
Current-Regulating Hot-Swap Controller wit
DualSpeed/BiLevel Fault Protection
MAX4370
VOUT
CBOARD
CTIM
CTIM
CSPD
CSPDON
GND
STAT
VCC
RSENSE
STAT
REMOVABLE CARDBACKPLANE
VINVSENGATE
GND
Typical Operating Circuit
19-1472; Rev 0; 4/99
PART
MAX4370ESA-40°C to +85°C
TEMP. RANGEPIN-PACKAGE
8 SO
Ordering Information
DualSpeed/BiLevel is a trademark of Maxim Integrated Products.
Pin Configuration appears at end of data sheet.
Current-Regulating Hot-Swap Controller with
DualSpeed/BiLevel Fault Protection
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN= +2.7V to +13.2V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VIN= +5V and TA= +25°C.) (Note 2)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Note 1:ON can be pulled below ground. Limiting the current to 2mA ensures that this pin is never lower than about -0.8V.
VINto GND...........................................................................+15V
STAT to GND..........................................................-0.3V to +14VGATE to GND..............................................-0.3V to (VIN+ 8.5V)
ON to GND (Note 1).................................................-1V to +14VCSPD to GND.............-0.3V to the lower of (VIN+ 0.3V) or +12V
VSEN, CTIM to GND....................................-0.3V to (VIN+ 0.3V) Current into ON...................................................................±2mA
Current into Any Other Pin................................................±50mA
Continuous Power Dissipation (TA= +70°C)SO (derate 5.9mW/°C above +70°C)...........................471mW
Operating Temperature Range...........................-40°C to +85°CStorage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10sec)............................+300°C
Start-up is initiated only if VGATEis less than this
voltage
ON = VIN
IGATE= 8.5µA, measured above VIN
Measured with respect to VIN; voltage at which
internal clamp circuitry is triggered
During start-up (current regulation provided by
fast comparator)
Time from current overload to VGATE< 0.1V,
CGATE= 1000pF to GND (triggered by the fast
comparator during normal operation)
VSEN = VIN
VGATE= VIN(Note 4)
CTIM = floating
10mV overdrive, from overload condition to GATE
discharging
VIN- VSEN
VIN- VSEN
CSPD = floating
100nF on CTIM
100nF on CSPD to GND
CONDITIONS0.1Gate Overvoltage Threshold2.7Minimum Gate Drive Voltage6.77.5Maximum Gate Voltage
Gate Discharge Current60tOFFTurn-Off Time100IGATEGate Charge Current5.5213141tSTARTStart-Up Period
(Note 3)0.61IQSupply Current2.713.2VINInput Voltage Range0.210IB,VSENVSEN Input Bias Current460tFCDFast Comparator Response
Time180200220VFC,THFast Comparator Threshold455055VSC,THSlow Comparator
Threshold102040tCSPDSlow Comparator Response
Timems102040
UNITSMINTYPMAXSYMBOLPARAMETER
During turn-off, triggered by a fault in normal
operation or ON falling edge225550
IGATE,DIS
POWER SUPPLIES
MOSFET DRIVER
CURRENT CONTROL
VIN‡5V
VIN‡2.7V= +25°C= TMINto TMAX43.556
Current-Regulating Hot-Swap Controller with
DualSpeed/BiLevel Fault Protection
ELECTRICAL CHARACTERISTICS (continued)
(VIN= +2.7V to +13.2V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at VIN= +5V and TA= +25°C.) (Note 2)
Note 2:All devices are 100% tested at TA = +25°C. All temperature limits are guaranteed by design.
Note 3:The start-up period (tSTART) is the time during which the slow comparator is ignored and the device acts as a current limiter
by regulating the sense current with the fast comparator. It is measured from ON rising above 0.6V to STAT rising.
Note 4:The current available at GATE is a function of VGATE(see TypicalOperating Characteristics.)
VIN= 5V, rising threshold
CONDITIONS3VHYSTHysteresis0.5750.60.625VTH,ONThreshold Voltage
UNITSMINTYPMAXSYMBOLPARAMETER
2.7V ≤VIN≤13.2VmV/V0.11PSRRPower-Supply Rejection
Ratio
Input can be driven to the absolute maximum
limit without false output inversionV-0.113.2
10mV overdrive
VONInput Voltage Range10tD,COMPPropagation Delay0.0011IB,ONInput Bias Current
To restart after a faultµs20tRESTARTON Pulse Width Low
VSTAT≤+13.2VµA1Output Leakage Current
ISINK= 1mAV0.4VOLOutput Voltage Low
Start-up is initiated when this threshold is
reached at VINV2.252.67VUVLOThreshold100VUVLO,HYSTHysteresis
Time which input voltage must exceed under-
voltage lockout before start-up is initiatedms100150200tD,UVLOUVLO to Start-Up Delay
DIGITAL OUTPUT(STAT)
ON COMPARATOR
VINUNDERVOLTAGE LOCKOUT
Current-Regulating Hot-Swap Controller with
DualSpeed/BiLevel Fault Protection
Typical Operating Characteristics
(Circuit of Figure 7, VIN= 5V, RSENSE= 100mΩ, M1 = FDS6670A, CBOARD= 470µF, CGATE= 0, RS= 0, TA= +25°C, unless other-
wise noted.)
SUPPLY CURRENT vs. INPUT VOLTAGE
X4370 toc01
VIN (V)
(mON = VIN
IGATE = 10mA
ON = GND
SUPPLY CURRENT vs. TEMPERATURE
AX4370 toc02
TEMPERATURE (°C)
(m
ON = VIN
VIN = 12V
VIN = 5V
VIN = 3V
SLOW COMPARATOR THRESHOLD
vs. INPUT VOLTAGE
AX4370 toc03
VIN (V)
, TH
(m
TA = -40°C
TA = +25°C
TA = +85°C
FAST COMPARATOR RESPONSE TIME
vs. OVERDRIVE VOLTAGE
AX4370 toc07
VOD (mV)
(n
VIN = 3V
VIN = 5V
VIN = 12V6824101214
SLOW COMPARATOR
RESPONSE TIME vs. INPUT VOLTAGE
MAX4370 toc05
VIN (V)
(m
(m
CSPD = 110nF
TIME IN ms
CSPD = 0
TIME IN ms
FAST COMPARATOR THRESHOLD
vs. INPUT VOLTAGE
4370 toc06
, T
(m2468101214
VIN (V)
TA = -40°C
TA = +25°C
TA = +85°C
FAST COMPARATOR RESPONSE TIME
vs. TEMPERATURE
X4370 toc08
TEMPERATURE (°C)
VIN = 12V
VIN = 3V
VOD = 10mV
VIN = 5V
START-UP TIME
vs. INPUT VOLTAGE
MAX4370 toc09
VIN (V)
(m
(m
CTIM = 100nF
TIME IN ms
CTIM = 1nF
TIME IN ms
Current-Regulating Hot-Swap Controller with
DualSpeed/BiLevel Fault Protection
GATE CHARGE CURRENT
vs. GATE VOLTAGE
4370 toc10
VGATE (V)
(m
VIN = 12V
VIN = 5.0VVIN = 3.0V
GATE CHARGE CURRENT
vs. TEMPERATURE
4370 toc11
TEMPERATURE (°C)
(m
VIN = 12V
VGATE = 0
VIN = 5V
VIN = 3V4268101214
GATE VOLTAGE vs. INPUT VOLTAGE
4370 toc12
VIN (V)
(V
IGATE = 10mA
TA = +85°C
TA = +25°C
TA = -40°C
GATE DISCHARGE CURRENT
vs. GATE VOLTAGE
AX4370 toc13
VGATE (V)
E (m
VIN = 12V
VIN = 3V
TRIGGERED BY A FAULT
OR BY ON FALLING
VIN = 5V
CBOARD = 0, RSENSE = 100mW,
CTIM = 10nF, CGATE = 0
VOUT
(2V/div)
VGATE
(2V/div)
100ms/div
START-UP TIME (CBOARD = 0)
MAX4370-16
GATE DISCHARGE CURRENT
vs. TEMPERATURE
X4370 toc14
TEMPERATURE (°C)
(m
VIN = 3V
VIN = 5V & 12V
VGATE = VIN
TRIGGERED BY A FAULT
OR BY ON FALLING
CBOARD = 470mF, RSENSE = 100mW,
CTIM = 10nF, CGATE = 0
ILOAD
(1A/div)
VOUT
(2V/div)
VGATE
(2V/div)
500ms/div
START-UP TIME (CBOARD = 470mF)
MAX4370-15
CBOARD = 470mF, RSENSE = 100mW,
CGATE = 22nF, CTIM = 10nF, RS = 0
ILOAD
(1A/div)
VOUT
(2V/div)
VGATE
(2V/div)
1ms/div
START-UP TIME
(EXTERNAL CGATE = 22nF, CBOARD = 470mF)
MAX4370-17
CBOARD = 470mF, RSENSE = 100mW,
CGATE = 0
ILOAD
(1A/div)
VOUT
(2V/div)
VGATE
(2V/div)
50ms/div
TURN-OFF TIME (CBOARD = 470mF)
MAX4370-18
Typical Operating Characteristics (continued)
(Circuit of Figure 7, VIN= 5V, RSENSE= 100mΩ, M1 = FDS6670A, CBOARD= 470µF, CGATE= 0, RS= 0, TA= +25°C, unless other-
wise noted.)
Current-Regulating Hot-Swap Controller with
DualSpeed/BiLevel Fault Protection
Typical Operating Characteristics (continued)
(Circuit of Figure 7, VIN= 5V, RSENSE= 100mΩ, M1 = FDS6670A, CBOARD= 470µF, CGATE= 0, RS= 0, TA= +25°C, unless other-
wise noted.)
CBOARD = 0, RSENSE = 100mW,
CGATE = 0, RS = 0
ILOAD
(1A/div)
VOUT
(2V/div)
VGATE
(2V/div)
50ms/div
TURN-OFF TIME (CBOARD = 0)
MAX4370-19
CBOARD = 470mF, RSENSE = 100mW,
CGATE = 22nF, RS = 0
ILOAD
(1A/div)
VOUT
(2V/div)
VGATE
(2V/div)
200ms/div
TURN-OFF TIME
(EXTERNAL CGATE = 22nF, CBOARD = 470mF)
MAX4370-20
TIME TO CHARGE GATE
vs. CGATE
4370 toc21
CGATE (nF)
(m
NO EXTERNAL MOSFET
VIN = 12V
TO VGATE = 17V
VIN = 5V
TO VGATE = 10V
VIN = 3V
TO VGATE = 6V
TIME TO DISCHARGE GATE
vs. CGATE
AX4370 toc22
CGATE (nF)
(m
1000
VIN = 12V
VIN = 5V
VIN = 3V
DISCHARGE TO VGATE=0.1V
NO EXTERNAL MOSFET
ON COMPARATOR THRESHOLD
vs. INPUT VOLTAGE
X4370 toc23
VIN (V)
(V
RISING
FALLING
ON COMPARATOR THRESHOLD
vs. TEMPERATURE
AX4370 toc24
TEMPERATURE (°C)
(V}
VIN = 12V
VIN = 5V
VIN = 3V
UVLO THRESHOLD VOLTAGE
vs. TEMPERATURE
AX4370 toc25
TEMPERATURE (°C)
(VRISING
FALLING
UVLO DELAY vs. TEMPERATURE
AX4370 toc26
TEMPERATURE (°C)
(m
s)
VIN = 3V
VIN = 5V & 12V
Current-Regulating Hot-Swap Controller with
DualSpeed/BiLevel Fault Protection
Pin Description
PIN
Supply Voltage Input. Connect to 2.7V to 13.2V.VIN1
FUNCTIONNAME
Current-Sense Resistor Voltage Input. RSENSEis connected from VINto VSEN.VSEN2
GroundGND4
Gate Drive Output. Connect to gate of external N-channel MOSFET.GATE3
Start-Up Timer Setting. Leave floating or connect the timing capacitor from CTIM to GND. See Start-Up
Timing Capacitorsection.CTIM6
ON Comparator Input. Connect high for normal operation; connect low to force the MOSFET off. Comparator
threshold VTH,ON= 0.6V allows for precise control over shutdown feature. Pulse ON low for at least 20µs,
then high to restart after a fault.8
Status Output—open drain. High indicates start-up completed with no fault. See Table 1.STAT7
Slow Comparator Speed Setting. Leave floating or connect the timing capacitor from CSPD to GND. See
Slow Comparator Response Timesection.CSPD5
MAX4370A
SLOW COMPARATOR
FAST COMPARATORA
2.45V
CSPD
CSPD
INPUT
UVLO
LOGIC
CONTROL
DISCHARGE
ENABLE
VIN
STAT
GND
CTIM
CTIMA
0.1V
0.6V
RSENSE
GATE
VSEN
VIN
GATE
OVLO
ON COMPARATOR
GATE
DRIVE
CHARGE
PUMP
VSC, TH
50mV
VFC, TH
200mV
150ms
DELAY
VIN RISING
VOUT
Figure 1. Functional Diagram
Current-Regulating Hot-Swap Controller with
DualSpeed/BiLevel Fault Protection
Detailed Description
The MAX4370 is a circuit-breaker IC designed for hot-swap applications where a card or board is to beinserted into a rack with the main system power supplyturned on. Normally, when a card is plugged into a livebackplane, the card is discharged filter capacitors pro-vide a low impedance, which can momentarily causethe main power supply to collapse. The MAX4370 isdesigned to reside either in the backplane or in theremovable card to provide inrush-current limiting andshort-circuit protection. This is achieved using a chargepump as gate drive for an external N-channel MOSFET,an external current-sense resistor, and two on-chipcomparators. Figure 1 shows the device’s functionaldiagram.
The slow comparator response time and the start-uptimer can be adjusted with external capacitors. The tim-ing components are optional; without them the part isset to its nominal values, as shown in the ElectricalCharacteristics.
Start-Up PeriodCTIM sets the start-up period. This mode starts whenthe power is first applied to VINif ON is connected toVIN, or at the rising edge of ON. In addition, the voltageat VINmust be above the undervoltage lockout for150ms (see Undervoltage Lockout).
During start-up, the slow comparator is disabled andcurrent limiting is provided two different ways:Slow ramping of the current to the load by controllingthe external MOSFET gate voltage.Limiting the current to the load by regulating the volt-age across the external current-sense resistor.
Unlike other circuit-breaker ICs, the MAX4370 hot-swapcontroller regulates the current to a preset level insteadof completely turning off if an overcurrent occurs duringstart-up.
In start-up mode, the gate drive current is limited to100µA and decreases with the increase of the gatevoltage (see Typical Operating Characteristics). Thisallows the MAX4370 to slowly enhance the MOSFET. Ifthe fast comparator detects an overcurrent, the gatevoltage is momentarily discharged with a fixed 80µAcurrent until the load current through the sense resistor(RSENSE) decreases below its threshold point. Thiseffectively regulates the turn-on current during start-up.Figure 2 shows the start-up waveforms. STAT goeshigh at the end of the start-up period if no fault condi-tion is present.
Normal Operation (DualSpeed/BiLevel)In normal operation (after the start-up period hasexpired), protection is provided by turning off the exter-nal MOSFET when a fault condition is encountered.DualSpeed/BiLevel fault protection incorporates twocomparators with different thresholds and responsetimes to monitor the load current:Slow Comparator. This comparator has an externallyset response time (20µs to seconds) and a fixed50mV threshold voltage. The slow comparatorignores low-amplitude momentary current glitches.After an extended overcurrent condition, a fault isdetected and the MOSFET gate is discharged.Fast Comparator. This comparator has a fixedresponse time and a higher 200mV threshold volt-age. The fast comparator turns off the MOSFETimmediately after it detects a large amplitude eventsuch as a short circuit.
In each case, when a fault is encountered, the statuspin (STAT) goes low and the MAX4370 stays latchedoff. Figure 3 shows the waveforms after a fault condi-tion.
tSTART
tON
~VIN
VGATE
IFAST, SET
VGATE
STAT
VTH
VOUT
CBOARD = LARGE
CBOARD = 0
VOUT
ILOAD
Figure 2. Start-Up Waveforms

Partno	Mfg	Dc	Qty	Available	Descript
MAX4370ESA+ \|MAX4370ESA	MAXIM	N/a	1600	avai	Current-Regulating Hot-Swap Controller with DualSpeed/BiLevel Fault Protection
MAX4370ESA+T \|MAX4370ESAT	MAX	N/a	2500	avai	Current-Regulating Hot-Swap Controller with DualSpeed/BiLevel Fault Protection