General Description
The MAX14571/MAX14572/MAX14573 adjustable over-
voltage and overcurrent-protection devices are ideal to
protect systems against positive and negative input volt-
age faults up to ±40V and feature low 100mΩ(typ) RON
FETs.
The overvoltage-protector (OVP) feature protects volt-
ages between 6V and 36V, while the undervoltage-protector
(UVP) feature protects voltages between 4.5V and 24V.
The overvoltage-lockout (OVLO) and undervoltage-lockout
(UVLO) thresholds are set using optional external resistors.
The factory-preset internal OVLO threshold is 33V (typ) and
the preset internal UVLO threshold is 19.2V (typ).
The ICs also feature programmable current-limit protec-
tion up to 4.2A. Once current reaches the threshold,
the MAX14571 turns off after the 20.7ms (typ) blanking
time and stays off during the retry period. The MAX14572
latches off after the blanking time, and the MAX14573 limits
the current continuously. In addition, these devices feature
reverse current and thermal-shutdown protection.
The ICs are available in a small 14-pin TSSOP (5mm
x 6.5mm) package and are specified over the extended
-40°C to +85°C temperature range.
Benets and Features
● Integrated Protection Increases System Reliability
● Adjustable OVLO and UVLO Thresholds
(±3% Accurate Preset Thresholds)
● Automatic Internal and External Selection
● Programmable Forward Current Limit (Adjustable Up
to 4.2A) with ±15% Accuracy
● Thermal-Shutdown Protection
● 100mΩ (typ) On-Resistance FET
●Special Features Facilitate Designs for Industrial
Applications
● Wide 4.5V to 36V Operating Input Range
● Reverse-Current Flow Option for Inductive Loads
● Independent Microprocessor Enable Input (EN) and
High-Voltage-Capable Input (HVEN)
Applications
●Industrial Equipment
●Consumer Electronics
●Marine Equipment
● Battery-Powered Applications
Ordering Information appears at end of data sheet.
19-6470; Rev 4; 7/17
Typical Operating Circuit
IN
IN
IN
UVLO
OVLO
SETI
OUT
OUT
VPULLUP
OUT
EN
RIEN
GND
R1
R2R4
R3
SYSTEM
INPUT
NOTE: R1, R2, R3, AND R4 ARE ONLY REQUIRED FOR ADJUSTABLE
OVLO/UVLO; OTHERWISE, CONNECT UVLO/OVLO TO GND.
SYSTEM
VPOWER
CIN COUT
FLAG
HVEN
MAX14571
MAX14572
MAX14573
MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
EVALUATION KIT AVAILABLE
(All voltages referenced to GND.)
IN, HVEN ................................................................-40V to +40V
IN to OUT ...............................................................-40V to +40V
OUT ......................................................................-0.3V to +40V
OVLO, UVLO, FLAG, EN, RIEN...........................-0.3V to +6.0V
Current into IN (DC Operating) (Note 1) .............. ………….4.2A
SETI..........................………….-0.3V to Min (VIN, 1.22V) + 0.3V
Continuous Power Dissipation (TA = +70NC)
TSSOP (derate 25.6mW/NC above +70NC) ....... ….2051.3mW
Operating Temperature Range ........................... -40NC to +85NC
Junction Temperature ......................................... ………..+150NC
Storage Temperature Range ............................ -65NC to +150NC
Lead Temperature (soldering, 10s) ...................…………+300NC
Soldering Temperature (reflow) .........................…………+260NC
Note 1: DC current is also limited by the thermal design of the system.
(VIN = 4.5V to 36V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at VIN = 24V, RSETI = 12kI, TA = +25°C.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
IN Voltage Range VIN 4.5 36 V
Shutdown Input Current ISHDN VEN = 0V, VHVEN = 5V 15 FA
Shutdown Output Current IOFF VOUT = 0V 2FA
Reverse Input Current IIN_RVS VIN = -40V, VOUT = VGND = 0V -35 FA
Supply Current IIN VIN = 15V, RISET = 12kI490 700 FA
Internal Overvoltage Trip Level VOVLO
VIN rising 32 33 34 V
VIN falling 32
Internal Undervoltage Trip Level VUVLO
VIN falling 17.5 18.5 19.5 V
VIN rising 18.2 19.2 20.2
Overvoltage-Lockout Hysteresis % of typical OVLO 3 %
PACKAGE TYPE: 14 TSSOP
Package Code U14E+3
Outline Number 21-0108
Land Pattern Number 90-0119
THERMAL RESISTANCE, FOUR-LAYER BOARD
Junction to Ambient (θJA) +39°C/W
Junction to Case (θJC) +3°C/W
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation 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.
Electrical Characteristics
Absolute Maximum Ratings
Package Information
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”,
or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains
to the package regardless of RoHS status.
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For
detailed informa¬tion on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
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2
MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
(VIN = 4.5V to 36V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at VIN = 24V, RSETI = 12kI, TA = +25°C.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
External OVLO Adjustment Range (Note 3) 6 36 V
External OVLO Select Voltage VOVLOSEL 0.3 0.50 V
External OVLO Leakage Current IOVLO_LEAK VOVLO < 1.2V (Note 4) -100 +100 nA
External UVLO Adjustment Range 4.5 24 V
External UVLO Select Voltage VOVLOSEL 0.3 0.50 V
External UVLO Leakage Current IUVLO_LEAK (Note 4) -100 +100 nA
BG Reference Voltage VBG 1.186 1.210 1.234 V
INTERNAL FETs
Internal FET On-Resistance RON ILOAD = 100mA, VIN R 8V 100 160 mI
Current-Limit Adjustment Range ILIM (Notes 4, 5) 0.7 4.2 A
Current-Limit Accuracy -15 +15 %
FLAG Assertion Drop Voltage
Threshold VFA Increase (VIN - VOUT) drop until FLAG
asserts, VIN = 24V 560 mV
Reverse Current Blocking Threshold VRIB VOUT - VIN 40 100 160 mV
Reverse Blocking Leakage Current IRBL VOUT - VIN > 160mV, current into OUT 400 600 FA
FLAG OUTPUT
FLAG Output Logic-Low Voltage ISINK = 1mA 0.4 V
FLAG Output Leakage Current VIN = VFLAG = 5V, FLAG desasserted 2FA
LOGIC INPUT
HVEN Threshold Voltage VHVEN_TH 1 2 3.5 V
HVEN Threshold Hysteresis 2 %
HVEN Input Leakage Current IHVEN_LEAK VHVEN = 36V 26 40 FA
HVEN Input Reverse Leakage
Current IHVEN_RLEAK VIN = VHVEN = -36V -45 -27 FA
EN, RIEN Input Logic-High VIH 1.4 V
EN, RIEN Input Logic-Low VIL 0.4 V
EN, RIEN Input Leakage Current IEN_LEAK,
IRIEN_LEAK VEN = VRIEN = 5.0V -1 +1 FA
THERMAL PROTECTION
Thermal Shutdown TJC_MAX Low-to-high temperature 150 NC
Thermal-Shutdown Hysteresis TJC_HYST High-to-low temperature 30 NC
TIMING CHARACTERISTICS (Note 6)
Switch Turn-On Time tON From OFF to IN, see Table 1. RLOAD =
240I, COUT = 470FF25 ms
Switch Turn-Off Time tOFF RLOAD = 47I3Fs
Electrical Characteristics (continued)
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3
MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
(VIN = 4.5V to 36V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at VIN = 24V, RSETI = 12kI, TA = +25°C.) (Note 2)
Note 2: All units are 100% production tested at TA = +25NC. Limits over the operating temperature range are guaranteed by design
and characterization; not production tested.
Note 3: Not production tested, user settable. See overvoltage/undervoltage lockout instructions.
Note 4: Guaranteed by design; not production tested. UVLO and OVLO are internally clamped to BG reference voltage.
Note 5: The current limit can be set below 700mA with a decreased accuracy.
Note 6: All timing is measured using 20% and 80% levels.
Note 7: The ratio between the autoretry time and blanking time is fixed and equal to 30.
Figure 1. Autoretry Fault Diagram
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Overvoltage Switch Turn-Off Time tOFF_OVP VIN > VOVLO to VOUT = 80% of VOVLO,
RLOAD = 47I, RSETI = 10kI3Fs
Overcurrent Switch Turn-Off Time tOFF_OCP IIN > ILIM, after tBLANK, ILIM = 1A 3Fs
IN Debounce Time tDEB VIN changes from 0V to greater than
VUVLO to VOUT = 10% of VIN 15.0 16.7 18.4 ms
Blanking Time tBLANK 18.6 20.7 22.8 ms
Autoretry Time tRETRY After blanking time from IOUT > ILIM to
FLAG clear (deassertion) (Note 7) 540 600 660 ms
ESD PROTECTION
IN
Human Body Model, IN bypassed
to GND with a 1FF low-ESR ceramic
capacitor
Q15 kV
tBLANK tBLANK tBLANK tBLANK
tRETRY tRETRY
tRETRY
NOTE:
TIME NOT IN SCALE
AUTORETRY VERSIONS
OUT
CURRENT LIMIT
LOAD CURRENT
FLAG
THE DEVICE GOES
TO THERMAL
SHUTDOWN MODE
THE DEVICE COMES
OUT OF THERMAL
SHUTDOWN MODE
Electrical Characteristics (continued)
Timing Diagrams
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MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
Figure 2. Latch-Off Fault Diagram
Figure 3. Continuous Fault Diagram
LATCH VERSION
OUT
CURRENT LIMIT
LOAD CURRENT
THE DEVICE GOES
TO THERMAL
SHUTDOWN MODE
THE DEVICE COMES
OUT OF THERMAL
SHUTDOWN MODE
NOTE:
TIME NOT IN SCALE
INPUT OR EN CYCLE
tBLANK tBLANK
FLAG
OUT
CURRENT LIMIT
LOAD CURRENT
FLAG
tBLANK
NOTE:
TIME NOT IN SCALE
THE DEVICE GOES TO
THERMAL SHUTDOWN MODE
THE DEVICE COMES OUT OF
THERMAL SHUTDOWN MODE
CONTINUOUS VERSIONS
Timing Diagrams (continued)
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MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
(TA = +25°C, unless otherwise noted.)
Figure 4. Debounce Timing
IN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX14571 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
353020 251510
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
54
0
SETI UNCONNECTED
TA = +85°C
TA = -40°C
TA = +25°C
IN SUPPLY CURRENT
vs. TEMPERATURE
MAX14571 toc02
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
603510-15
0.1
0.2
VIN = +24V
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
-40 85
SETI UNCONNECTED
NORMALIZED ON-RESISTANCE
vs. SUPPLY VOLTAGE
MAX14571 toc03
SUPPLY VOLTAGE (V)
NORMALIZED ON-RESISTANCE
211815
0.8
0.9
1.0
1.1
1.2
1.3
0.7
12 24
TA = -40°C
TA = +25°C
TA = +85°C
IOUT = 100mA
VIN
SWITCH
STATUS
UVLO
THRESHOLD
ON
OFF
< tDEB < tDEB tDEB
NOTE: TIME NOT IN SCALE
Typical Operating Characteristics
Timing Diagrams (continued)
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6
MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
(TA = +25°C, unless otherwise noted.)
NORMALIZED ON-RESISTANCE
vs. TEMPERATURE
MAX14571 toc04
TEMPERATURE (°C)
NORMALIZED ON-RESISTANCE
603510-15
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
0.5
-40 85
VIN = +24V
NORMALIZED CURRENT LIMIT
vs. SUPPLY VOLTAGE
MAX14571 toc05
SUPPLY VOLTAGE (V)
NORMALIZED CURRENT LI MIT
322923 2611 14 17 208
0.92
0.94
0.96
0.98
1.00
1.02
1.04
1.06
1.08
1.10
0.90
53
5
RSETI = 17.4kI
NORMALIZED CURENT LIMIT
vs. TEMPERATURE
MAX14571 toc06
TEMPERATURE (°C)
60
3510-15-40 85
NORMALIZED CURRENT LI MIT
0.92
0.94
0.96
0.98
1.00
1.02
1.04
1.06
1.08
1.10
0.90 VIN = +24V
NORMALIZED OVLO THRESHOLD
vs. TEMPERATURE
MAX14571 toc07
TEMPERATURE (°C)
60
3510-15-40 85
NORMALIZED OVLO THRESHOLD
0.92
0.94
0.96
0.98
1.00
1.02
1.04
1.06
1.08
1.10
0.90 VIN = +24V
SHUTDOWN REVERSE CURRENT
vs. TEMPERATURE
MAX14571 toc10
TEMPERATURE (°C)
SHUTDOWN SUPPLY CURRENT (µA)
603510-15
5
10
15
20
25
30
35
0
-40 85
VIN = -24V
EN = LOW
HVEN = 100kI PULLUP TO VIN
OUT = OVLO = UVLO = GND
NORMALIZED UVLO THRESHOLD
vs. TEMPERATURE
MAX14571 toc08
TEMPERATURE (°C)
60
3510-15-40 85
NORMALIZED UVLO THRESHOLD
0.92
0.94
0.96
0.98
1.00
1.02
1.04
1.06
1.08
1.10
0.90 VIN = +24V
TURN-ON TIME
vs. TEMPERATURE
MAX14571 toc11
TEMPERATURE (°C)
TURN-ON TIME (ms)
603510-15
2
4
6
8
10
12
14
16
18
20
0
-40 85
EN TRANSITION TO 10% OF VIN
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX14571 toc09
TEMPERATURE (°C)
SHUTDOWN SUPPLY CURRENT (µA)
603510-15
5
10
15
20
25
0
-40 85
VIN = +24V
EN = LOW
HVEN = 100kI PULLUP TO VIN
OUT = OVLO = UVLO = GND
TURN-OFF TIME
vs. TEMPERATURE
MAX14571 toc12
TEMPERATURE (°C)
TURN-OFF TIME (µs)
603510-15
10
20
30
40
50
60
70
80
90
100
0
-40 85
EN TRANSITION TO 90% OF VOUT
COUT = 10µF
RLOAD = 480I
Typical Operating Characteristics (continued)
Maxim Integrated
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MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
PIN NAME FUNCTION
1, 2, 3 IN
Overvoltage-Protection Input. Bypass IN to GND with a 1FF ceramic capacitor placed as close
as possible to the device. Use a 1FF, low-ESR ceramic capacitor to enable Q15kV (HBM) ESD
protection on IN. For hot-plug applications, see the Applications Information section.
4UVLO
Externally Programmable Undervoltage-Lockout Threshold. Connect UVLO to GND to use the
default internal UVLO threshold. Connect UVLO to an external resistor-divider to define a threshold
externally and override the preset internal UVLO threshold.
5OVLO
Externally Programmable Overvoltage-Lockout Threshold. Connect OVLO to GND to use the
default internal OVLO threshold. Connect OVLO to an external resistor-divider to define a threshold
externally and override the preset internal OVLO threshold.
6 SETI
Overload Current-Limit Adjust. Connect a resistor from SETI to GND to program the overcurrent
limit. If SETI is unconnected, the current limit is set to 0A. If SETI is connected to GND, the FETs
turn off and FLAG is asserted. Do not connect more than 10pF to SETI.
7GND Ground
8HVEN
Active-Low Enable Input. HVEN is a high-voltage-capable enable input. Drive HVEN low for normal
operation. Drive HVEN high to disable the device. HVEN has up to 36V overvoltage protection at
the input (Table 1).
9 RIEN Reverse-Current Enable Input. Connect RIEN to GND to disable the reverse-current flow protection.
Connect RIEN to logic-high to activate the reverse-current flow protection.
10 EN Active-High Enable Input. Drive EN high for normal operation. Drive EN low to disable the device
(Table 1).
11 FLAG
Open-Drain, Fault Indicator Output. FLAG goes low when the fault duration exceeds the blanking
time, reverse current is detected, thermal-shutdown mode is active, OVLO threshold is reached, or
SETI is connected to GND.
12, 13, 14 OUT
Output Voltage. Output of internal FETs. Bypass OUT to GND with a 1FF ceramic capacitor placed
as close as possible to the device. For a long output cable or inductive lead, see the Applications
Information section.
—EP Exposed Pad. Internally connected to GND. Connect EP to a large ground plane to maximize
thermal performance. Do not use EP as the single GND connection.
14
13
12
11
10
9
8
1
2
3
4
5
6
7
OUT
OUT
OUT
UVLO
IN
IN
IN
TOP VIEW
MAX14571
MAX14572
MAX14573 EN
RIEN
GND
SETI
OVLO
*EP
TSSOP
*CONNECT EXPOSED PAD TO GND
FLAG
HVEN
+
Pin Conguration
Pin Description
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MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
N
REVERSE-INPUT
REVERSE-CURRENT
PROTECTION
CONTROL LOGIC
THERMAL
SHUTDOWN
V
BG
OVLO
SETI GND
UVLO
IN
IN
IN OUT
OUT
OUT
RIEN
FLAG
EN
HVEN
V
SEL
MAX14571
MAX14572
MAX14573
V
SEL
Functional Diagram
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9
MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
Detailed Description
The MAX14571/MAX14572/MAX14573 are adjust-
able overvoltage- and overcurrent-protection devices
designed to protect systems against positive and nega-
tive input voltage faults up to Q40V, and feature low
100mΩ (typ) on-resistance FETs. If the input voltage
exceeds the OVLO threshold or falls below the UVLO,
the internal FETs are turned off to prevent damage to the
protected components. If the OVLO or the UVLO pin is
set below the external OVLO or UVLO select thresholds
(VOVLOSEL and VUVLOSEL), the device automatically
selects the internal Q3% (typ) accurate trip thresholds.
The internal OVLO threshold is preset to 33V (typ), and
the internal UVLO threshold is preset to 19.2V (typ).
The ICs feature programmable current-limit protection
up to 4.2A. Once current reaches the threshold, the
MAX14571 turns off after 20.7ms (typ) blanking time and
stays off during the retry period. The MAX14572 latches
off after the blanking time, and the MAX14573 limits the
current continuously.
Programmable Current Limit/Threshold
A resistor from SETI to GND sets the current limit/
threshold for the switch (see the Setting the Current Limit/
Threshold section). If the output current is limited at the
current threshold value for a time equal to or longer than
tBLANK, the output FLAG asserts and the MAX14571
enters the autoretry mode, the MAX14572 latches off the
switch, and the MAX14573 enters the continuous current-
limit mode.
Autoretry (MAX14571)
When the current threshold is reached, the tBLANK timer
begins counting. The FLAG asserts if the overcurrent
condition is present for tBLANK. The timer resets if the
overcurrent condition disappears before tBLANKK has
elapsed. A retry time delay, tRETRY, is started immediately
after tBLANK has elapsed and during tRETRY time, the
FETs are off. At the end of tRETRY, the FETs are turned
on again. If the fault still exists, the cycle is repeated and
the FLAG stays low. When the fault is removed, the FETs
stay on. If the die temperature exceeds +150NC (typ) due
to self-heating, the MAX14571 enables thermal shutdown
until the die temperature drops by approximately 30NC
(Figure 1).
The autoretry feature reduces the system power in case
of overcurrent or short-circuit conditions. During tBLANK
time, when the switch is on, the supply current is held at
the current limit. During tRETRY time, when the switch
is off, there is no current through the switch. Thus, the
output current is much less than the programmed current
limit. Calculate the average output current using the fol-
lowing equation:
BLANK
LOAD LIM BLANK RETRY
t
II
tt
=
+
With a 20.7ms (typ) tBLANK and 600ms (typ) tRETRY, the
duty cycle is 3.3%, resulting in a 96.7% power savings.
Latch-O (MAX14572)
When the current threshold is reached, the tBLANK timer
begins counting. The FLAG asserts if the overcurrent
condition is present for tBLANK. The timer resets when
the overcurrent condition disappears before tBLANK has
elapsed. The switch turns off and stays off if the over-
current condition continues beyond the blanking time.
To reset the switch, either toggle the control logic EN or
HVEN or cycle the input voltage. If the die temperature
exceeds +150NC (typ) due to self-heating, the MAX14572
latches off (Figure 2).
Continuous Current Limit (MAX14573)
When the current threshold is reached, the MAX14573
limits the output current to the programmed current limit.
The FLAG asserts if the overcurrent condition is present
for tBLANK and deasserts when the overload condition is
removed. If the die temperature exceeds +150NC (typ) due
to self-heating, the MAX14573 enables thermal shutdown
until the die temperature drops by approximately 30NC
(Figure 3).
Reverse-Current Enable (RIEN)
This feature disables the reverse-current protection
and enables reverse-current flow from OUT to IN. The
reverse-current enable feature is useful in applications
with inductive loads.
Fault Flag Output
FLAG is an open-drain fault indicator output and requires
an external pullup resistor to a DC supply. FLAG goes low
when any of the following conditions occur:
• The blanking time has elapsed.
• The reverse-current protection has tripped.
• The die temperature exceeds +150NC.
• SETI is connected to ground.
• OVLO threshold is reached.
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MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
Thermal-Shutdown Protection
The devices have a thermal-shutdown feature to pro-
tect them from overheating. The devices turn off and the
FLAG asserts when the junction temperature exceeds
+150NC (typ). The devices exit thermal shutdown and
resume normal operation after the junction temperature
cools by 30NC (typ), except for the MAX14572, which re-
mains latched off.
The thermal limit behaves similarly to the current limit. For
the MAX14571 (autoretry), the thermal limit works with the
autoretry timer. When the device comes out of the thermal
limit, it starts after the retry time. For the MAX14572 (latch
off), the device latches off until power or EN cycle. For the
MAX14573 (continuous), the device only disables while
the temperature is over the limit. There is no blanking time
for thermal protection.
Overvoltage Lockout (OVLO)
The devices have a 33V (typ) preset OVLO threshold
when the voltage at OVLO is set below the external
OVLO select voltage (VOVLOSEL). Connect OVLO to
GND to activate the preset OVLO threshold. Connect the
external resistors to the OVLO pin as shown in the Typical
Operating Circuit to externally adjust the OVLO threshold.
Use the following equation to adjust the OVLO threshold.
The recommended value for R3 is 2.2MI:
OVLO BG
R3
V V1
R4
= ×+
Undervoltage Lockout (UVLO)
The devices have a 19.2V (typ) preset UVLO threshold
when the voltage at UVLO is set below the external
UVLO select voltage (VUVLOSEL). Connect UVLO to
GND to activate the preset UVLO threshold. Connect the
external resistors to the UVLO pin as shown in the Typical
Operating Circuit to externally adjust the UVLO threshold.
Use the following equation to adjust the UVLO threshold.
The recommended value for R1 is 2.2MI:
UVLO BG
R1
V V1
R2
= ×+
Switch Control
There are two independent enable inputs (HVEN and EN)
for the devices. HVEN is a high-voltage-capable input.
Toggle HVEN or EN to reset the fault condition once a short
circuit is detected and the devices shut down (Table 1).
Input Debounce Protection
The ICs feature input debounce protection. When the
input voltage is higher than the UVLO threshold voltage
for a period greater than the debounce time (tDEB), the
internal FETs are turned on. This feature is intended for
applications where the EN or HVEN signal is present
when the power supply ramps up (Figure 4).
Applications Information
Setting the Current Limit/Threshold
A resistor from SETI to ground programs the current limit/
threshold value for the devices. Leaving SETI uncon-
nected selects a 0A current limit/threshold. Connecting
SETI to ground asserts FLAG. Use the following formula
to calculate the current limit:
Ω=
SETI LIM
11500
R (k ) I (mA)
IN Bypass Capacitor
Connect a minimum of 1FF capacitor from IN to GND
to limit the input voltage drop during momentary output
short-circuit conditions. Larger capacitor values further
reduce the voltage undershoot at the input.
Hot-Plug IN
In many system powering applications, an input-filtering
capacitor is required to lower the radiated emission,
enhance the ESD capability, etc. In hot-plug applications,
parasitic cable inductance, along with the input capacitor,
cause overshoot and ringing when the powered cable is
connected to the input terminal.
This effect causes the protection device to see almost
twice the applied voltage. A transient voltage suppressor
(TVS) is often used for industrial applications to protect
the system from these conditions. We recommend us-
ing a TVS that is capable of limiting surge to 40V (max)
placed close to the input terminal.
Table 1. Switch Control
HVEN EN SWITCH STATUS
0 0 On
1 0 Off
0 1 On
1 1 On
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MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
OUT Bypass Capacitor
For stable operation over the full temperature range
and over the entire programmable current-limit range,
connect a 1μF ceramic capacitor from OUT to ground.
Excessive output capacitance can cause a false overcur-
rent condition due to decreased dV/dt across the capaci-
tor. Calculate the maximum capacitive load (CMAX) value
that can be connected to OUT by using the following
formula:
=LIM BLANK(MIN)
MAX IN
I (mA) x t (ms)
C (µF) V (V)
For example, for VIN = 24V, tBLANK = 15ms, and ILIM =
4.2A, CMAX equals 2625FF.
Output Freewheeling Diode for
Inductive Hard Short to Ground
In applications that require protection form a sudden short
to ground with an inductive load or long cable, a Schottky
diode between the OUT terminal and ground is recom-
mended. This is to prevent a negative spike on OUT due
to the inductive kickback during a short-circuit event.
Layout and Thermal Dissipation
To optimize the switch response time to output short-
circuit conditions, it is very important to keep all traces
as short as possible to reduce the effect of undesirable
parasitic inductance. Place input and output capacitors as
close as possible to the device (no more than 5mm). IN
and OUT must be connected with wide short traces to the
power bus. During normal operation, the power dissipa-
tion is small and the package temperature change is mini-
mal. If the output is continuously shorted to ground at the
maximum supply voltage, the switches with the autoretry
option do not cause thermal-shutdown detection to trip:
IN(MAX) OUT(MAX) BLANK
(MAX) RETRY BLANK
V I t
Pt t
××
=+
Attention must be given to the MAX14573 continuous
current-limit version when the power dissipation during a
fault condition can cause the device to reach the thermal-
shutdown threshold. Thermal vias from the exposed pad
to ground plane are highly recommended to increase the
system thermal capacitance while reducing the thermal
resistance to the ambient.
ESD Test Conditions
The devices are specified for Q15kV (HBM) typical ESD
resistance on IN when IN is bypassed to ground with a
1FF low-ESR ceramic capacitor. No capacitor is required
for Q2kV (HBM) typical ESD on IN. All the pins have a
Q2kV (HBM) typical ESD protection.
HBM ESD Protection
Figure 5a shows the Human Body Model, and Figure 5b
shows the current waveform it generates when dis-
charged into a low impedance. This model consists of a
100pF capacitor charged to the ESD voltage of interest,
which is then discharged into the device through a 1.5kΩ
resistor.
Figure 5a. Human Body ESD Test Model Figure 5b. Human Body Current Waveform
CHARGE-CURRENT-
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Cs
100pF
RC
1MI
RD
1.5kI
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
IP 100%
90%
36.8%
tRL TIME
tDL
CURRENT WAVEFORM
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
IR
10%
0
0
AMPERES
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MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
*EP = Exposed pad.
/V denotes an automotive qualified part.
Chip Information
PROCESS: BiCMOS
Ordering Information
PART TEMP
RANGE
PIN-
PACKAGE
OVERCURRENT
PROTECTION
MAX14571EUD+T -40NC to
+85NC
14 TSSOP-
EP* Autoretry
MAX14571EUD/V+T -40NC to
+85NC
14 TSSOP-
EP* Autoretry
MAX14572EUD+T -40NC to
+85NC
14 TSSOP-
EP* Latchoff
MAX14573EUD+T -40NC to
+85NC
14 TSSOP-
EP* Continuous
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MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 9/12 Initial release —
1 12/12 Removed future product asterisk and notes for the MAX14571/MAX14573,
style edits. 1–6, 8, 10, 11, 14
2 1/15 Updated Benefits and Features section 1
3 6/16 Updated Functional Diagram 9
4 7/17
Updated Hot-Plug IN section, and added MAX14571EUD/V+T to the
Ordering Information table. Corrections to SETI in the Typical Operating
Circuit, HVEN in Benefits and Features, and RSETI in the Electrical
Characteristics table.
1, 2–4, 11, 14
Revision History
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. © 2017 Maxim Integrated Products, Inc.
│
14
MAX14571/MAX14572/
MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
