MAXIM MAX14571

EVALUATION KIT AVAILABLE
MAX14571/MAX14572/MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
General Description
Features
The MAX14571/MAX14572/MAX14573 adjustable overvoltage and overcurrent-protection devices are ideal
to protect systems against positive and negative input
voltage faults up to Q40V and feature low 100mI (typ)
RON FETs.
S Wide 4.5V to 36V Operating Input Range
S Adjustable OVLO and UVLO Thresholds
±3% Accurate Preset Thresholds
Automatic Internal and External Selection
S Programmable Forward Current Limit
Adjustable Current Limit Up to 4.2A
±15% Accuracy Limit
The overvoltage-protector (OVP) feature protects voltages
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).
S 100mω (typ) On-Resistance FET
S Dual-Enable Inputs
High-Voltage-Capable Input HVEN
Microprocessor Input EN
The ICs also feature programmable current-limit protection 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.
S Reverse Current Flow Control Input RIEN
S Thermal-Shutdown Protection
Ordering Information
The ICs are available in a small 14-pin TSSOP (5mm x
6.5mm) package and are specified over the extended
-40NC to +85NC temperature range.
Applications
Industrial Equipment
Consumer Electronics
Marine Equipment
Battery-Powered Applications
PART
TEMP
RANGE
PINOVERCURRENT
PACKAGE PROTECTION
MAX14571EUD+T*
-40NC to
+85NC
14 TSSOPEP**
Autoretry
MAX14572EUD+T
-40NC to
+85NC
14 TSSOPEP**
Latchoff
MAX14573EUD+T*
-40NC to
+85NC
14 TSSOPEP**
Continuous
+Denotes a lead(Pb)-free/RoHS-compliant package.
*Future product—contact factory for availability.
T = Tape and reel.
**EP = Exposed pad.
Typical Operating Circuit
VPOWER
CIN
IN
OUT
IN
OUT
OUT
IN
SYSTEM
INPUT
R3
MAX14571
MAX14572
MAX14573
R1
UVLO
R4
R2
OVLO
FLAG
EN
SET1
RIEN
COUT
VPULLUP
SYSTEM
HVEN
GND
NOTE: R1, R2, R3, AND R4 ARE ONLY REQUIRED FOR ADJUSTABLE
OVLO/UVLO; OTHERWISE, CONNECT UVLO/OVLO TO GND.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-6470; Rev 0; 9/12
MAX14571/MAX14572/MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
ABSOLUTE MAXIMUM RATINGS
(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.
PACKAGE THERMAL CHARACTERISTICS (Note 2)
TSSOP
Junction-to-Ambient Thermal Resistance (BJA)............ +39NC/W
Junction-to-Case Thermal Resistance (BJC)................... +3NC/W
Note 2: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
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
(VIN = 4.5V to 36V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at VIN = 24V, TA = +25NC, RISET = 12kI.) (Note 3)
PARAMETER
IN Voltage Range
Shutdown Input Current
Shutdown Output Current
Reverse Input Current
Supply Current
SYMBOL
CONDITIONS
MAX
UNITS
36
V
VEN = 0V, VHVEN = 5V
15
FA
VOUT = 0V
2
FA
VIN
ISHDN
IOFF
IIN_RVS
IIN
Internal Overvoltage Trip Level
VOVLO
Internal Undervoltage Trip Level
VUVLO
VIN = -40V, VOUT = VGND = 0V
VIN rising
BG Reference Voltage
2 34
32
19.5
VIN rising
18.2
19.2
20.2
(Note 5) VOVLO < 1.2V
VOVLOSEL
VBG
700
33
18.5
VOVLOSEL
IUVLO_LEAK
490
17.5
External UVLO Adjustment Range
External UVLO Leakage Current
FA
VIN falling
(Note 4)
External UVLO Select Voltage
32
VIN falling
% of typical OVLO
IOVLO_LEAK
-35
VIN = 15V, RISET = 12kI
External OVLO Adjustment Range
External OVLO Leakage Current
TYP
4.5
Overvoltage-Lockout Hysteresis
External OVLO Select Voltage
MIN
(Note 5)
3
6
FA
V
V
%
36
V
0.3
0.50
V
-100
+100
nA
4.5
24
V
0.3
0.50
V
-100
+100
nA
1.234
V
1.186
1.210
Maxim Integrated
MAX14571/MAX14572/MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 4.5V to 36V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at VIN = 24V, TA = +25NC, RISET. = 12kI) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
100
INTERNAL FETs
Internal FETs On-Resistance
RON
ILOAD = 100mA, VIN R 8V
Current-Limit Adjustment Range
ILIM
(Notes 5, 6)
Current-Limit Accuracy
FLAG Assertion Drop Voltage
Threshold
VFA
Increase (VIN - VOUT) drop until FLAG
asserts, VIN = 24V
Reverse Current Blocking Threshold
VRIB
VOUT - VIN
Reverse Blocking Leakage Current
IRBL
VOUT - VIN > 160mV, current into OUT
160
mI
0.7
4.2
A
-15
+15
%
560
40
mV
100
160
mV
400
600
FA
FLAG OUTPUT
FLAG Output Logic-Low Voltage
ISINK = 1mA
FLAG Output Leakage Current
VIN = VFLAG = 5V, FLAG desasserted
0.4
V
2
FA
3.5
V
LOGIC INPUT
HVEN Threshold Voltage
1
VHVEN_TH
2
HVEN Threshold Hysteresis
HVEN Input Leakage Current
IHVEN_LEAK
HVEN Input Reverse Leakage
Current
IHVEN_RLEAK VIN = VHVEN = -36V
EN, RIEN Input Logic-High
VIH
EN, RIEN Input Logic-Low
VIL
EN, RIEN Input Leakage Current
2
IEN_LEAK,
IRIEN_LEAK
26
VHVEN = 36V
-45
%
40
-27
FA
1.4
VEN = VRIEN = 5.0V
FA
V
-1
0.4
V
+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 7)
Switch Turn-On Time
tON
From OFF to IN, see Table 1. RLOAD =
240I, COUT = 470FF.
25
ms
Switch Turn-Off Time
tOFF
RLOAD = 47I
3
Fs
Overvoltage Switch Turn-Off Time
tOFF_OVP
VIN > VOVLO to VOUT = 80% of VOVLO,
RLOAD = 47I, RSETI = 10kI
3
Fs
Overcurrent Switch Turn-Off Time
tOFF_OCP
IIN > ILIM, after tBLANK, ILIM = 1A
3
Fs
IN Debounce Time
tDEB
Blanking Time
tBLANK
Autoretry Time
tRETRY
Maxim Integrated
VIN changes from 0V to greater than
VUVLO to VOUT = 10% of VIN
After blanking time from IOUT > ILIM to
FLAG clear (deassertion) (Note 8)
15.0
16.7
18.4
ms
18.6
20.7
22.8
ms
540
600
660
ms
3
MAX14571/MAX14572/MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 4.5V to 36V, TA = -40NC to +85NC, unless otherwise noted. Typical values are at VIN = 24V, TA = +25NC, RISET. = 12kI) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ESD PROTECTION
Human Body Model, IN bypassed
to GND with a 1FF low-ESR ceramic
capacitor
IN
Q15
kV
Note 3: 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 4: Not production tested, user settable. See overvoltage/undervoltage lockout instructions.
Note 5: Guaranteed by design; not production tested. UVLO and OVLO are internally clamped to BG reference voltage.
Note 6: The current limit can be set below 700mA with a decreased accuracy.
Note 7: All timing is measured using 20% and 80% levels.
Note 8: The ratio between autoretry time and blanking time is fixed and equal to 30.
Timing Diagrams
AUTORETRY VERSIONS
tBLANK
tRETRY
tBLANK
tRETRY
tBLANK
tBLANK
tRETRY
OUT
THE DEVICE COMES
OUT OF THERMAL
SHUTDOWN MODE
CURRENT LIMIT
LOAD CURRENT
THE DEVICE GOES
TO THERMAL
SHUTDOWN MODE
FLAG
NOTE: TIME NOT IN SCALE
Figure 1. Autoretry Fault Diagram
4 Maxim Integrated
MAX14571/MAX14572/MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
LATCH VERSION
tBLANK
tBLANK
OUT
CURRENT LIMIT
LOAD CURRENT
THE DEVICE GOES
TO THERMAL
SHUTDOWN MODE
THE DEVICE COMES
OUT OF THERMAL
SHUTDOWN MODE
INPUT OR EN CYCLE
FLAG
NOTE: TIME NOT IN SCALE
Figure 2. Latchoff Fault Diagram
CONTINUOUS VERSIONS
tBLANK
OUT
THE DEVICE COMES OUT OF
THERMAL SHUTDOWN MODE
CURRENT LIMIT
LOAD CURRENT
THE DEVICE GOES TO
THERMAL SHUTDOWN MODE
FLAG
NOTE: TIME NOT IN SCALE
Figure 3. Continuous Fault Diagram
Maxim Integrated
5
MAX14571/MAX14572/MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
< tDEB
< tDEB
tDEB
UVLO
THRESHOLD
VIN
ON
OFF
SWITCH
STATUS
NOTE: TIME NOT IN SCALE
Figure 4. Debounce Timing
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
IN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
TA = +85°C
0.5
0.4
0.3
TA = +25°C
0.2
0.7
0.6
0.5
0.4
0.3
0.2
TA = -40°C
0.1
0.1
0
0
5
10
15
20
25
30
SUPPLY VOLTAGE (V)
6 35
40
MAX14571 toc03
0.8
1.3
NORMALIZED ON-RESISTANCE
0.7
SETI UNCONNECTED
0.9
SUPPLY CURRENT (mA)
SUPPLY CURRENT (mA)
0.8
MAX14571 toc02
SETI UNCONNECTED
0.6
1.0
MAX14571 toc01
1.0
0.9
NORMALIZED ON-RESISTANCE
vs. SUPPLY VOLTAGE
IN SUPPLY CURRENT
vs. TEMPERATURE
1.2
TA = +85°C
1.1
TA = +25°C
1.0
0.9
TA = -40°C
0.8
VIN = +24V
-40
-15
10
35
TEMPERATURE (°C)
60
IOUT = 100mA
0.7
85
12
15
18
21
24
SUPPLY VOLTAGE (V)
Maxim Integrated
MAX14571/MAX14572/MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
1.1
1.0
0.9
0.8
0.7
0.6
-15
10
35
60
1.00
0.98
0.96
0.94
85
8
MAX14571 toc06
1.04
1.02
1.00
0.98
0.96
0.94
0.92
RSETI = 17.4kI
5
1.06
VIN = +24V
0.90
11 14 17 20 23 26 29 32 35
-40
-15
10
35
60
TEMPERATURE (°C)
NORMALIZED OVLO THRESHOLD
vs. TEMPERATURE
NORMALIZED UVLO THRESHOLD
vs. TEMPERATURE
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
1.02
1.00
0.98
0.96
0.94
0.92
-15
10
35
60
1.04
1.02
1.00
0.98
0.96
0.94
0.92
VIN = +24V
0.90
1.06
VIN = +24V
0.90
85
25
-40
-15
10
35
60
20
15
10
VIN = +24V
EN = LOW
HVEN = 100kI PULLUP TO VIN
OUT = OVLO = UVLO = GND
5
0
-40
85
-15
10
35
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
SHUTDOWN REVERSE CURRENT
vs. TEMPERATURE
TURN-ON TIME
vs. TEMPERATURE
TURN-OFF TIME
vs. TEMPERATURE
25
20
15
VIN = -24V
EN = LOW
HVEN = 100kI PULLUP TO VIN
OUT = OVLO = UVLO = GND
10
5
14
12
10
8
6
-15
10
35
TEMPERATURE (°C)
Maxim Integrated
60
85
90
80
70
60
50
40
30
4
20
2
10
EN TRANSITION TO 10% OF VIN
0
0
-40
-15
10
35
TEMPERATURE (°C)
60
85
85
MAX14571 toc12
16
TURN-OFF TIME (µs)
30
18
60
100
MAX14571 toc11
20
MAX14571 toc10
35
85
MAX14571 toc09
1.08
SHUTDOWN SUPPLY CURRENT (µA)
1.04
1.10
MAX14571 toc08
MAX14571 toc07
1.06
-40
1.08
SUPPLY VOLTAGE (V)
1.08
NORMALIZED OVLO THRESHOLD
1.02
1.10
TEMPERATURE (°C)
1.10
-40
1.04
0.90
NORMALIZED UVLO THRESHOLD
-40
1.06
0.92
VIN = +24V
0.5
SHUTDOWN SUPPLY CURRENT (µA)
1.08
NORMALIZED CURRENT LI MIT
1.2
MAX14571 toc05
1.3
1.10
TURN-ON TIME (ms)
NORMALIZED ON-RESISTANCE
1.4
NORMALIZED CURRENT LI MIT
MAX14571 toc04
1.5
NORMALIZED CURENT LIMIT
vs. TEMPERATURE
NORMALIZED CURRENT LIMIT
vs. SUPPLY VOLTAGE
NORMALIZED ON-RESISTANCE
vs. TEMPERATURE
EN TRANSITION TO 90% OF VOUT
COUT = 10µF
RLOAD = 480I
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
7
MAX14571/MAX14572/MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
Pin Configuration
TOP VIEW
IN
1
IN
2
IN
3
UVLO
4
OVLO
5
SETI
6
GND
7
+
14 OUT
13 OUT
12 OUT
MAX14571
MAX14572
MAX14573
11 FLAG
10 EN
*EP
9
RIEN
8
HVEN
TSSOP
*CONNECT EXPOSED PAD TO GND
Pin Description
PIN
NAME
1, 2, 3
IN
4
UVLO
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.
5
OVLO
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.
7
GND
Ground
8
HVEN
Active-Low Enable Input. HVEN is 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
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
8 FUNCTION
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.
Active-High Enable Input. Drive EN high for normal operation. Drive EN low to disable the device
(Table 1).
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.
Maxim Integrated
MAX14571/MAX14572/MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
Functional Diagram
MAX14571
MAX14572
MAX14573
IN
OUT
OUT
IN
OUT
REVERSE-INPUT
REVERSE-CURRENT
PROTECTION
IN
RIEN
FLAG
N
CONTROL LOGIC
VBG
EN
UVLO
HVEN
VSEL
THERMAL
SHUTDOWN
OVLO
VSEL
SETI
Maxim Integrated
GND
9
MAX14571/MAX14572/MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
Detailed Description
The MAX14571/MAX14572/MAX14573 are adjustable overvoltage and overcurrent-protection devices
designed to protect systems against positive and negative input voltage faults up to Q40V, and feature low
100mI (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).


t BLANK
ILOAD = ILIM 

t
t
+
 BLANK RETRY 
With a 20.7ms (typ) tBLANK and 600ms (typ) tRETRY, the
duty cycle is 3.3%, resulting in a 96.7% power saving.
Latch-Off (MAX14572)
Programmable Current Limit/Threshold
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
overcurrent 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.)
Autoretry (MAX14571)
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).
The ICs feature programmable current-limit protection
up to 4.2A. Once current reaches the threshold, the
MAX14571 turns off after 20.6ms (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.
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.
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 tBLANK 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
10 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
following equation:
Continuous Current Limit (MAX14573)
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.
Maxim Integrated
MAX14571/MAX14572/MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
Thermal-Shutdown Protection
The MAX14571/MAX14572/MAX14753 have a thermalshutdown feature to protect the device from overheating.
The device turns 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 remains 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.
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 unconnected selects a 0A current limit/threshold. Connecting
SETI to ground asserts FLAG. Use the following formula
to calculate the current limit:
11500
R SETI (kΩ) =
ILIM (mA)
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:
 R3 
VOVLO= VBG × 1 +

 R4 
Undervoltage Lockout (UVLO)
The devices have a 19.2V (typ) preset UVLO threshold
when the voltage at UVLO is set below the external
OVLO 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:
 R1
VUVLO= VBG × 1 +

 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).
Maxim Integrated
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. An input voltage of 24V can
easily exceed the absolute maximum rating of 40V, which
may permanently damage the device. A transient voltage
suppressor (TVS) is often used for industrial applications
to protect the system from these conditions. We recommend using a TVS that is capable of limiting surge to 40V
placed close to the input terminal.
Table 1. Switch Control
HVEN
0
EN
SWITCH STATUS
0
On
1
0
Off
0
1
On
1
1
On
11
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 1FF ceramic capacitor from OUT to ground.
Excessive output capacitance can cause a false overcurrent condition due to decreased dV/dt across the
capacitor. Calculate the maximum capacitive load
(CMAX) value that can be connected to OUT by using
the following formula:
C MAX (µF) =
ILIM (mA) x t BLANK(MIN) (ms)
VIN (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 recommended. This is to prevent a negative spike on
OUT due to the inductive kickback during a short-circuit
event.
Thermal-Shutdown Protection
The MAX14571/MAX14572/MAX14573 have a thermalshutdown feature to protect the device from overheating. The device turns off and the FLAG asserts when the
junction temperature exceeds +150°C (typ). The devices
exit thermal shutdown and resume normal operation after
the junction temperature cools by 30°C (typ), except for
the MAX14572, which remains latched off.
The thermal limit behaves similar to the current limit. For
the MAX14571 (autoretry), the thermal limit works with
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.
12 Layout and Thermal Dissipation
To optimize the switch response time to output shortcircuit 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 dissipation is small and the package temperature
change is minimal. 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:
P(MAX) =
VIN(MAX) × IOUT(MAX) × t BLANK
t RETRY + t BLANK
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 discharged 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 1.5kI
resistor.
Maxim Integrated
MAX14571/MAX14572/MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
RC
1MI
CHARGE-CURRENTLIMIT RESISTOR
RD
1.5kI
IP 100%
90%
DISCHARGE
RESISTANCE
IR
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
AMPERES
HIGHVOLTAGE
DC
SOURCE
Cs
100pF
STORAGE
CAPACITOR
DEVICE
UNDER
TEST
36.8%
10%
0
0
TIME
tDL
tRL
CURRENT WAVEFORM
Figure 5a. Human Body ESD Test Model
Figure 5b. Human Body Current Waveform
Chip Information
PROCESS: BiCMOS
Maxim Integrated
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
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND PATTERN
NO.
14 TSSOP-EP
U14E+3
21-0108
90-0119
13
MAX14571/MAX14572/MAX14573
Adjustable Overvoltage and Overcurrent
Protectors with High Accuracy
Revision History
REVISION
NUMBER
REVISION
DATE
0
9/12
DESCRIPTION
Initial release
PAGES
CHANGED
—
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 specifications 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.
14
© 2012
Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
Maxim Integrated Products, Inc.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.