Typical Application Circuit appears at end of data sheet.
Ordering Information appears at end of data sheet.
For related parts and recommended products to use with this
part, refer to www.maximintegrated.com/MAX15091.related.
General Description
The MAX15091/MAX15091A ICs are integrated solutions
for hot-swap applications requiring the safe insertion and
removal of circuit line cards from a live backplane. The
devices integrate a hot-swap controller, 18mΩ (typ) power
MOSFET, and an electronic circuit-breaker protection in a
single package.
The devices integrate an accurate current-sense circuitry
and provide 170µA/A of proportional output current. The
devices are designed for protection of 2.7V to 18V supply
voltages.
These devices implement a foldback current limit during
startup to control inrush current lowering di/dt and keep the
MOSFET operating under safe operating area (SOA) con-
ditions. After the startup cycle is complete, on-chip compar-
ators provide VariableSpeed/BiLevel™ protection against
short-circuit and overcurrent faults, and immunity against
system noise and load transients. The load is disconnect-
ed in the event of a fault condition. The devices are factory
calibrated to deliver accurate overcurrent protection with
±10% accuracy. During a fault condition, the MAX15091
latches off, while the MAX15091A enters autoretry mode.
The devices feature an IN to OUT short-circuit detection
before startup. The devices provide a power-MOSFET
GATE pin to program the slew rate during startup by add-
ing an external capacitor. The devices have overvoltage/
undervoltage input pins that can detect an overvoltage/
undervoltage fault and disconnect the IN from the OUT.
Additional features include internal overtemperature pro-
tection, power-good output, and fault-indicator output.
The MAX15091/MAX15091A are available in a 28-pin,
5mm x 5mm TQFN power package and are rated over the
-40°C to +85°C extended temperature range.
Benets and Features
● Integration Reduces Solution Size for Blade Servers
and Other Space-Constrained Designs
• Integrated 18mΩ (typ) Internal Power MOSFET
• Overvoltage Protection
• Power-Good and Fault Outputs
• Analog Current Report Output without Need for
External RSENSE
• Thermal Protection
● Flexibility Enables Use in Many Unique Designs
• 2.7V to 18V Operating Voltage Range
• Programmable Inrush Current Control Under SOA
Operation
• Adjustable Circuit-Breaker Current/Current-Limit
Threshold
• Programmable Slew-Rate Control
• Programmable Undervoltage Lockout
• Variable-Speed Circuit-Breaker Response
• Latchoff or Automatic Retry Options
● Safety Features Ensure Accurate, Robust Protection
• 9A (max) Load Current Capability
• ±10% Circuit-Breaker Threshold Accuracy
• Inrush Current Regulated at Startup with Foldback
• Implementation for di/dt Control
• IN-to-OUT Short-Circuit Detection
Applications
● Blade Servers
● Server I/O Cards
● RAID Systems
● Disk Drive Power
● Storage Applications
● Industrial Applications
VariableSpeed/BiLevel is a trademark of Maxim Integrated
Products, Inc.
19-6625; Rev 2; 1/15
EVALUATION KIT AVAILABLE
MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
VCC to GND ..........................................................-0.3V to +20V
IN to GND .............................................................. -0.3V to +20V
OUT to GND ...............................................-0.3V to (VIN + 0.3V)
GATE to OUT ..........................................................-0.3V to +6V
CDLY, ISENSE to GND ..........................-0.3V to (VREG + 0.3V)
EN, CB, UV, OV to GND .........................................-0.3V to +6V
REG to GND ............................-0.3V to min (+6V, (VCC + 0.3V))
PG, FAULT to GND ...............................................-0.3V to +20V
Continuous Power Dissipation (TA = +70NC)
TQFN (derate 34.5mW/NC above +70NC)...............2758.6mW
Operating Temperature Range ........................... -40NC to +85NC
Junction Temperature ...................................................... +150NC
Storage Temperature Range ............................ -60NC to +150NC
Lead Temperature (soldering, 10s) .................................+300NC
Soldering Temperature (reflow) ....................................... +260NC
Junction-to-Ambient Thermal Resistance (qJA) ..............29°C/W
Junction-to-Case Thermal Resistance (qJC) .....................2°C/W
(VIN = VCC = 2.7V to 18V, TA = TJ = -40°C to +85°C, unless otherwise noted. Typical values are at VIN = 12V, RCB = 25kΩ, and TA
= +25°C.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
POWER SUPPLIES
VCC Operating Range VCC 2.7 18 V
IN Operating Range VIN 2.7 18 V
VCC Supply Current ICC VIN = 3V 0.4 0.65 mA
IN Supply Current IIN
RCB = 25kΩ, no load 3.3 3.6 mA
RCB = 10kΩ, no load 1.75 2
VCC Default Undervoltage
Lockout VUVLO VCC rising 2.35 2.5 2.65 V
VCC Default Undervoltage-
Lockout Hysteresis VUVLO_HYS 0.1 V
REG Regulator Voltage VREG No load, VCC > 4V 3 3.3 3.5 V
UV Turn-On Threshold VUV_TH VUV rising 1.18 1.2 1.22 V
UV Turn-On Threshold
Hysteresis VUV_HYS VUV falling 0.1 V
OV Turn-On Threshold VOV_TH VOV rising 1.18 1.2 1.22 V
OV Turn-On Threshold
Hysteresis VOV_HYS VOV falling 0.1 V
EN Threshold VEN_TH VEN rising 0.95 1 1.05 V
EN Threshold Hysteresis VEN_HYS VEN falling 0.1 V
Absolute Maximum Ratings
Package Thermal Characteristics (Note 1)
Electrical Characteristics
Note 1: 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.
Thermal resistance can be lowered with improved board design.
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.
MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
www.maximintegrated.com Maxim Integrated
│
2
(VIN = VCC = 2.7V to 18V, TA = TJ = -40°C to +85°C, unless otherwise noted. Typical values are at VIN = 12V, RCB = 25kΩ, and TA
= +25°C.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
OV, UV, EN Input Leakage
Current ILEAK VOV = VUV = VEN = 0 to 5V -1 +1 µA
CB Source Current ITHCB_NORM Power-on mode 12 µA
CURRENT LIMIT
Circuit-Breaker Accuracy
(Note 3) ICB,TH VIN = 12V RCB = 25kΩ 8 9 10 A
RCB = 8.33kΩ 2.7 3 3.3
Circuit-Breaker Accuracy
Deviation
RCB = 8.33kΩ to 25kΩ, compared to
nominal current-limit value -10 +10 %
Slow-Comparator Response
Time (Note 4) tSCD
0.6% overcurrent 2.7 ms
30% overcurrent 200 µs
Maximum Current Limit
During Startup ILIM (see Figure 2) ICB,TH A
Fast-Comparator Threshold IFC_TH
1.5 x
ICB,TH
A
Fast-Comparator Response
Time tFCD 200 ns
Minimum CB Voltage
Reference During Foldback
(Note 5)
VTHCB_MIN VIN - VOUT > 10V, RCB = 25kΩ 35 mV
Maximum CB Voltage
Reference During Foldback
(Note 5)
VTHCB_MAX VIN - VOUT < 2V, RCB = 25kΩ 150 mV
TIMING
Startup Maximum Time
Duration tSU 43 48 53 ms
Autorestart Delay Time tRESTART 3.2 s
Time Delay Comparator
High Threshold VDLY_TH 1.85 2 2.15 V
Time Delay Pullup Current IDLY 1.6 1.9 2.2 µA
Output Short Detection at
Startup tSHORT 10.8 12 13.2 ms
MOSFET
Total On-Resistance RON
TA = +25°C 18 23 mΩ
TA = -40°C to +85°C 27
GATE Charge Current IGATE 4.56 5.7 6.84 µA
Electrical Characteristics (continued)
MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
www.maximintegrated.com Maxim Integrated
│
3
(VIN = VCC = 2.7V to 18V, TA = TJ = -40°C to +85°C, unless otherwise noted. Typical values are at VIN = 12V, RCB = 25kΩ, and TA
= +25°C.) (Note 2)
Note 2: All devices are 100% production tested at TA = +25°C. Limits over temperature are guaranteed by design.
Note 3: 25kΩ is the maximum allowed external resistance value to be connected at CB pin to GND for safe operation. All devices
are tested with 8.33kΩ, the parameter specified at RCB = 25kΩ is guaranteed by bench characterization and correlation,
with respect to the tested parameter at RCB = 8.33kΩ. The formula that describes the relationship between RCB and the
circuit-breaker current threshold is: ICB = RCB/2777.8.
Note 4: The current-limit slow-comparator response time is weighed against the amount of overcurrent so the higher the
overcurrent condition, the faster the response time.
Note 5: Foldback is active during the startup phase so the internal power MOSFET operates within SOA.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
OUTPUTS
FAULT, PG Output Low
Voltage VOL
Low-impedance state,
IFAULT = +5mA, IPG = +5mA 0.4 V
FAULT, PG Output High
Leakage Current IOH
High-impedance state,
VFAULT = 16V, VPG = 16V 1 µA
CURRENT REPORT
ISENSE Full-Scale Current IISENSE 1.53 mA
ISENSE Gain Ratio ISENSE/IOUT 170 µA/A
ISENSE Voltage Range VISENSE VIN = 12V 0 2.5 V
ISENSE Offset Error IISENSE_OFF
TA = +25°C -32 +32 µA
TA = -40°C to +85°C -45 +45
ISENSE Gain Error IISENSE_ERROR
TA = +25°C -3 +3 %
TA = -40°C to +85°C -5.5 +5.5
PG THRESHOLD
PG Threshold VPG Measured at VOUT, VIN = 12V 0.9 x
VIN
V
PG Assertion Delay tPG From VOUT > VPG and
(VGATE - VIN) > 3V 12 16 20 ms
OUT to IN Short-Circuit
Detection Threshold VIOSHT Measured at VOUT, VIN = 12V 0.9 x
VIN
V
OUT Precharge Threshold VPC Measured at VOUT, VIN = 12V 0.5 x
VIN
V
THERMAL SHUTDOWN
Thermal Shutdown TSD TJ rising +150 °C
Thermal-Shutdown Hysteresis TJ falling 20 °C
Electrical Characteristics (continued)
MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
www.maximintegrated.com Maxim Integrated
│
4
(VIN = VCC = 2.7V to 18V, TJ = -40°C to +85°C, unless otherwise noted. Typical values are at VIN = 12V, RCB = 25kΩ, and
TJ = +25°C.) (Note 3)
IN SUPPLY CURRENT
vs. TEMPERATURE
MAX15091 toc01
TEMPERATURE (°C)
IIN SUPPLY CURRENT (mA)
603510-15
3.15
3.20
3.25
3.30
3.10
-40 85
VIN = 12V
CIRCUIT-BREAKER THRESHOLD
vs. TEMPERATURE
MAX15091 toc03
TEMPERATURE (°C)
CIRCUIT-BREAKER THRESHOLD (A)
603510-15
2
4
8
6
10
12
14
0
-40 85
VIN = 12V
RCB = 25kΩ
RCB = 20kΩ
RCB = 15kΩ
RCB = 8.2kΩ
TURN-ON WAVEFORM
MAX15091 toc05
10ms/div
VUV
2V/div
VOUT
10V/div
VPG
10V/div
ILOAD
5A/div
0V
0V
0V
0A
ILOAD = 3.5A
NORMAL TURN-OFF WAVEFORM
MAX15091 toc06
10ms/div
VUV
2V/div
VOUT
10V/div
VPG
10V/div
ILOAD
5A/div
0V
0V
0V
0A
ILOAD = 3.5A
CIRCUIT-BREAKER THRESHOLD
vs. CIRCUIT-BREAKER RESISTANCE
MAX15091 toc02
RCB (Ω)
CIRCUIT-BREAKER THRESHOLD (A)
201510
2
4
6
8
10
12
0
5 25
VIN = 12V
ON-RESISTANCE vs. TEMPERATURE
MAX15091 toc04
TEMPERATURE (°C)
ON-RESISTANCE (mΩ)
603510-15
15
20
25
10
-40 85
VIN = 12V
ILOAD = 1A
Typical Operating Characteristics
Maxim Integrated
│
5
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MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
(VIN = VCC = 2.7V to 18V, TJ = -40°C to +85°C, unless otherwise noted. Typical values are at VIN = 12V, RCB = 25kΩ, and
TJ = +25°C.) (Note 3)
Typical Operating Characteristics (continued)
FAULT-SHUTDOWN WAVEFORM
OVERLOAD (SLOW TRIP)
MAX15091 toc07
1ms/div
VOUT
10V/div
VPG
10V/div
ILOAD
10A/div
VFAULT
10V/div
0V
0A
0V
0V
CIRCUIT-BREAKER THRESHOLD
vs. TEMPERATURE
MAX15091 toc09
TEMPERATURE (°C)
CIRCUIT-BREAKER THRESHOLD (A)
603510-15
1.1
1.2
1.3
1.4
1.0
-40 85
VIN = 12V
VUV RISING
VUV FALLING
AUTORETRY FUNCTIONALITY
MAX15091 toc11
1s/div
VOUT
10V/div
ILOAD
10A/div
VPG
10V/div
VFAULT
10V/div
0V
0A
0V
0V
CIRCUIT-BREAKER THRESHOLD TIME
vs. OVERCURRENT
MAX15091 toc12
OVERCURRENT (%)
CIRCUIT-BREAKER THRESHOD TIME (ms)
252015105
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
0
0.2
0 30
VIN = 12V
FAULT-SHUTDOWN WAVEFORM
OVERLOAD (SHORT CIRCUIT)
MAX15091 toc08
1ms/div
VOUT
10V/div
VPG
10V/div
ILOAD
5A/div
VFAULT
10V/div
0V
0A
0V
0V
PG ASSERTION DELAY
MAX15091 toc10
10ms/div
VUV
1V/div
VOUT
5V/div
VPG
5V/div
0V
0V
0V
Maxim Integrated
│
6
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MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
MAX15091
MAX15091A
TQFN
TOP VIEW
26
27
25
24
10
9
11
IN
IN
IN
IN
IN
12
IN
OUT
OUT
OUT
OUT
OUT
OUT
1 2
GND
4 5 6 7
2021 19 17 16 15
GND
CB
FAULT
EN
CDLY
GATE
IN OUT
3
18
28 8
ISENSE VCC
+
REG
23 13 PG
UV
22 14 GND
OV
*CONNECT EXPOSED PAD TO GND.
*EP
PIN NAME FUNCTION
1–7 IN
Supply Voltage Input. IN is connected to the drain of the internal 18mΩ MOSFET. Bypass IN with a
transient voltage-suppressor diode to GND for clamping inductive kick transients in the case of fast
output short-circuit to GND.
8 VCC
Power-Supply Input. Connect VCC to a voltage between 2.7V and 18V. Connect a Schottky diode (or
10Ω resistor) from IN to VCC and a 1µF bypass capacitor to GND to guarantee full operation in the event
VIN collapses during a strong short from OUT to GND.
9 GATE
GATE of Internal MOSFET. During startup, a 5.7µA current is sourced to enhance the internal MOSFET
with a 10V/ms slew rate. Connect an external capacitance from GATE to GND to reduce the output slew
rate during startup.
Pin Description
Pin Conguration
MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
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7
Detailed Description
Enable Logic and Undervoltage/
Overvoltage-Lockout Threshold
The MAX15091/MAX15091A ICs enable the output, as
shown in Table 1. The devices are ready to drive the out-
put when the VCC supply rises above the VUVLO thresh-
old. The devices turn on the output when VCC > VUVLO,
VUV is high (VUV > 1.2V) and VOV is low (VOV < 1.2V).
The devices turn off the output when VUV falls below
(1.2V - VUV_HYS) or VOV rises above 1.2V. An external
resistive divider from IN to UV, OV, and ground provide
the flexibility to set the undervoltage/overvoltage-lockout
threshold to any desired level between VUVLO and 18V.
See Figure 1 and the Setting the Undervoltage Threshold
and Setting the Overvoltage Threshold sections.
PIN NAME FUNCTION
10 CDLY
Enable Timer Input. Connect a capacitor between CDLY and GND to set a 1s/µF duration timeout
delay. The EN input has to be pulled low before the timeout delay elapses, to prevent internal
MOSFET shutdown after power-up.
11 EN
Enable Input. Externally pulled up to logic-high state through a resistor normally connected to REG. The
EN input must be pulled down (for at least 1ms) by the external circuit before a programmable timeout
delay has elapsed, otherwise a shutdown occurs. The timeout timer starts counting when the internal
MOSFET is turned on. Connect a capacitor between CDLY and GND to program the duration of the
timeout delay. Connect EN to GND to disable this feature.
12 FAULT Fault Status Output. FAULT is an open-drain, active-low output. FAULT asserts low when an overcurrent
or overtemperature condition triggers a shutdown. FAULT is disabled during startup.
13 PG Power-Good Output. PG is an open-drain, active-high output. PG pulls low until the internal power
MOSFET is fully enhanced.
14, 25, 26 GND Ground
15–21 OUT Load Output. Source of the internal power MOSFET.
22 OV
Overvoltage Enable Input. Pull OV high to turn off the internal MOSFET. Connect OV to an external
resistive divider to set the overvoltage-disable threshold. See the Setting the Overvoltage Threshold
section.
23 UV Active-High Enable Comparator Input. Pulling UV high enables the internal MOSFET to turn on. UV also
sets the undervoltage threshold. See the Setting the Undervoltage Threshold section.
24 REG Internal Regulator Output. Bypass to ground with a 1µF capacitor. Do not power external circuitry using
the REG output (except a resistor > 50kΩ connected from REG to EN).
27 CB
Current-Limit Threshold Set. Connect a resistor from CB to GND to set the circuit-breaker threshold. Maximum
value of 25kΩ can be accepted for safe operation. Having the CB pin connected to GND sets the circuit-
breaker threshold at 0A.
28 ISENSE Current-Sense Output. The ISENSE output sources a current that is proportional to the output current.
Connect a resistor between ISENSE and GND to produce a scaled voltage.
—EP
Exposed Pad. Connect EP to GND externally. Do not use EP as an electrical connection to GND. EP
is internally connected to GND through a resistive path and must be connected to GND externally. To
optimize power dissipation, solder the exposed pad to a large copper power plane. Do not leave EP
unconnected.
Pin Description (continued)
MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
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8
Startup
Once the device output is enabled, the device provides
controlled application of power to the load. The voltage at
OUT begins to rise at approximately 10V/ms default until
the programmed circuit-breaker current level is reached,
while the devices actively limit the inrush current at the
circuit-breaker setting. An external capacitor connected to
the GATE pin allows the user to program the slew rate to
a value lower than the default. The inrush current can be
pro grammed by selecting the appropriate value of RCB.
During startup, a foldback current limit is active to protect
the internal MOSFET to operate within the SOA (Figure 2).
An internal 48ms timer starts counting when the devices
enter the startup phase. The devices complete the startup
phase and enter normal operation mode if the voltage
at OUT rises above the precharge threshold (0.9 x VIN)
and (VGATE - VOUT) > 3V. An open-drain power-good
output (PG) goes high-impedance 16ms after the startup
successfully completes.
The thermal-protection circuit is always active and the
internal MOSFET immediately turned off when the
thermal-shutdown threshold condition is reached.
VariableSpeed/BiLevel Fault Protection
VariableSpeed/BiLevel fault protection incorporates com-
parators with different thresholds and response times to
monitor the load current (Figure 3). Protection is provided
in normal operation (after the startup period has expired)
by discharging the MOSFET gate in response to a fault
condition. During a fault condition, the MAX15091A enters
autoretry mode, while the MAX15091 latches off (see the
Autoretry and Latch-Off Fault Management section).
Enable Input (EN)
After a startup phase is successfully completed and the
power-good output asserted, the EN input has to be pulled
low (for at least 1ms) before the tDLY delay elapses. If the
EN input is not pulled low before the tDLY elapses, then
the devices turn off the internal MOSFET immediately
and a new cycle is required for entering power-up mode.
Connect a capacitor between CDLY and GND to set a 1s/
µF duration timeout delay. If this function in is not imple-
mented, connect EN to GND for proper operation.
Table 1. Output Enable Truth Table
X = Don’t care.
VUV_TH and VOV_TH = 1.2V (typ).
Figure 1. Undervoltage/Overvoltage-Threshold Setting
POWER SUPPLY PRECISION ANALOG INPUTS OUT
VCC UV OV
VCC > VUVLO VUV > VUV_TH VOV < VOV_TH On
VCC < VUVLO X X Off
X VUV < (VUV_TH - VUV_HYS)XOff
X X VOV > VOV_TH Off
MAX15091
MAX15091A
IN
UV
OV
GND
1.2V
R1
R2
R3
CONTROL
LOGIC
MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
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9
Figure 2. Startup Inrush Current Foldback Characteristics
Figure 3. VariableSpeed/BiLevel Response
IINRUSH
2V 10V
4.5A
1.5A
1A
0.25A
VIN - VOUT
RCB = 25kΩ
RCB = 8.33kΩ
2.7ms
200ns
TURN-OFF TIME
OUT CURRENT
SLOW COMPARATOR
FAST COMPARATOR
0.6%
OVERCURRENT
30%
OVERCURRENT
50%
OVERCURRENT
200µs
MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
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│
10
Charge Pump
An integrated charge pump provides the gate-drive volt-
age for the internal power MOSFET. The charge pump
generates the proper gate drive voltage above VIN to fully
enhance the internal power MOSFET and guarantee low
RON operation during normal state conditions.
During startup, the internal charge pump drives the GATE
of the MOSFET with a fixed 5.7µA current to enhance the
internal MOSFET with 10V/ms slew rate (typ). Connect
an external capacitor (CGATE) from GATE to GND to
reduce the output slew rate during startup. CGATE can be
calculated according to the following formula:
CGATE = (IGATE x ∆t)/∆VGATE
where IGATE is 5.7µA (typ), Dt is the desired slew-rate
time, and ∆VGATE is the voltage at the gate of the internal
MOSFET at turn-on.
The slew rate of the OUT pin during startup can be
controlled by IGATE/CGATE under light-load driving
conditions, or by the limited inrush current and the exter-
nal capacitive load, whichever is less.
(∆VOUT/∆t) = ILIM/CLOAD
Circuit-Breaker Comparator
and Current Limit
The current that passes through the internal power
MOSFET is com pared to a circuit-breaker threshold. An
external resistor between CB and GND sets this threshold
according to the following formula:
ICB = RCB/2777.8
where ICB is in amps and RCB (the resistor between CB
and GND) is in ohms.
The circuit-breaker comparator is designed so the load
current can exceed the threshold for some amount of
time before tripping. The time delay varies inversely with
the overdrive above the threshold. The greater the over-
current condition, the faster the response time, allow ing
the devices to tolerate load transients and noise near the
circuit-breaker threshold. The maximum allowed external
resistor value is 25kΩ, which corresponds to a 9A CB
threshold setting. Programming the CB threshold to a
value higher than 9A could cause unsafe operating condi-
tions, resulting in damage to the devices.
The devices also feature catastrophic short-circuit protec-
tion. During normal operation, if OUT is shorted directly
to GND, a fast protection circuit forces the gate of the
internal MOSFET to discharge quickly and disconnect the
output from the input.
Autoretry and Latch-Off Fault Management
During a fault condition, the devices turn off the inter nal
MOSFET, disconnecting the output from the input. The
MAX15091A enters autoretry mode and restarts after
a tRESTART time delay has elapsed. The MAX15091
latches off and remains off until the enable logic is cycled
off and on after a tRESTART delay. The delay prevents
the latch-off device to restart and operate with an unsafe
power-dissipation duty cycle.
Fault-Status Output (FAULT)
FAULT is an open-drain output that asserts low when
a current-limit or an overtemperature-fault shutdown
occurs. FAULT remains low until the next startup cycle.
FAULT is capable of sinking up to 5mA current when
asserted.
Power-Good (PG) Delay
The devices feature an open-drain, power-good output
that asserts after a tPG delay, indicating that the OUT volt-
age has reached (0.9 x VIN) voltage and (VGATE - VOUT)
> 3V.
Internal Regulator Output (REG)
The devices include a linear regulator that outputs 3.3V
at REG. REG provides power to the internal circuit blocks
of the devices and must not be loaded externally (except
for a resistor > 50kΩ connected from REG to EN). REG
requires at least a 1µF capacitor to ground for proper
operation.
Current Report Output (ISENSE)
The ISENSE pin is the output of an accurate current-
sense amplifier and provides a source current that is pro-
portional to the load current flowing into the main switch.
The factory-trimmed current ratio is set to 170µA/A.
This produces a scaled voltage by connecting a resistor
between ISENSE and ground. This voltage signal then
goes to an ADC and provides digitized information of the
current supplied to the powered system.
MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
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11
Thermal Protection
The devices enter a thermal-shutdown mode in the event
of overheating caused by excessive power dissipation or
high ambient temperature. When the junction tem perature
exceeds TJ = +150°C (typ), the internal thermal-protec-
tion circuitry turns off the internal power MOSFET. The
devices recover from thermal-shutdown mode once the
junction temperature drops by 20°C (typ).
IN to OUT Short-Circuit Protection
At startup, after all the input conditions are satisfied (UV,
OV, VUVLO), the devices immediately check for an IN to
OUT short-circuit fault. If VOUT is greater than 90% of
VIN, the internal MOSFET cannot be turned on so FAULT
is asserted and the MAX15091A enters autoretry mode in
3.2s, while the MAX15091 latches off.
If VOUT is lower than 90% of VIN but greater than 50%
of VIN, the internal MOSFET still cannot be turned on. No
fault is asserted and the MOSFET can turn on as soon as
VOUT is lower than 50% of VIN.
Applications Information
Setting the Undervoltage Threshold
The devices feature an independent on/off control (UV)
for the internal MOSFET. The devices operate with a 2.7V
to 18V input voltage range and have a default 2.5V (typ)
undervoltage-lockout threshold.
The internal MOSFET remains off as long as VCC < 2.5V
or VUV < VUV_TH. The undervoltage-lockout threshold
is pro grammable using a resistive divider from IN to UV,
OV, and GND (Figure 1). When VCC is greater than 2.7V
and VUV exceeds the 1.2V (typ) threshold, the internal
MOSFET turns on and goes into normal operation. Use
the following equation to calculate the resistor values for
the desired undervoltage threshold:
(
)
-
IN
UV_TH
V
R1 1 R2 R3
V
= ×+
where VIN is the desired turn-on voltage for the output
and VUV_TH is 1.2V. R1 and (R2 + R3) create a resistive
divider from IN to UV. During normal operating conditions,
VUV must remain above its 1.2V (typ) threshold. If VUV
falls 100mV (VUV_HYS) below the threshold, the internal
MOSFET turns off, disconnecting the load from the input.
Setting the Overvoltage Threshold
The devices also feature an independent overvoltage-
enable control (OV) for the internal MOSFET.
When VOV exceeds the 1.2V (typ) threshold, the internal
MOSFET turns off.
The overvoltage-lockout threshold is pro grammable using
a resistive divider from IN to UV, OV, and GND (Figure 1).
Use the following equation to calculate the resistor values
for the desired overvoltage threshold:
( )
-
IN
OV_TH
V
R1 R2 1 R3
V
+= ×
where VIN is the desired turn-off voltage for the output
and VOV_TH is 1.2V. R1 and (R2 + R3) create a resistive
divider from IN to OV. During normal operating conditions,
VOV must remain below its 1.2V (typ) threshold. If VOV
rises above the VOV_TH threshold, the internal MOSFET
turns off and disconnects the load from the input.
MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
www.maximintegrated.com Maxim Integrated
│
12
Functional Diagram
MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
www.maximintegrated.com Maxim Integrated
│
13
MAX15091
MAX15091A
UV
OV
CDLY
1.2V
2V
1.9µA
TEMP
SENSE
STARTUP
CONTROL AND
FOLDBACK
CONTROL
LOGIC 2 x ISLEW
IPD
IGATE
IREF
MS1
VCC
GATE
IN OUT
ISENSE
FAULT
PG
12µA
CB
GATE_OK
REFERENCE
GENERATOR
REGEN
LDO
REGULATOR
DLY
CTRL
ILOAD/5882
CB_SLOW_COMP
FAST_COMP
MPOW
CHARGE
PUMP
0.9 x VIN
VCC
1.2V
GATE
ILOAD
GND
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
PART TEMP
RANGE
PIN-
PACKAGE
FAULT
MANAGEMENT
MAX15091ETI+ -40NC to
+85NC
28 TQFN-
EP* Latched Off
MAX15091AETI+ -40NC to
+85NC
28 TQFN-
EP* Autoretry PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND PATTERN
NO.
28 TQFN T2855+8 21-0140 90-0028
MAX15091
MAX15091A
RIN
RCB
RPG
CIN
TVS
IN
VCC
UV
12V
OV
EN
GND
CB
REG
RFAULT
R1
R2
R3
CREG
GATE
OUT
PG
FAULT
ISENSE
DC-DC
REGULATOR
3.3V OUTPUT
A/D
CONVERTER
CGATE
CDLY
CCDLY
RISENSE
Ordering Information
Chip Information
PROCESS: BiCMOS
Typical Application Circuit
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.
MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
www.maximintegrated.com Maxim Integrated
│
14
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 3/13 Initial release —
1 9/13 Removed future product marking from MAX15091A 14
2 1/15 Updated Benets and Features section 1
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. © 2015 Maxim Integrated Products, Inc.
│
15
MAX15091/MAX15091A 2.7V to 18V, 9A, Integrated Hot-Swap
Solution with Current Report Output
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.
