19-1988; Rev 1; 9/02
+72V SOT23 Simple Swapper Hot-Swap
Controllers
MAX5902/MAX5903
General Description
The MAX5902/MAX5903 are SOT23 hot-swap con-
trollers that allow a circuit card to be safely hot plugged
into a live backplane without causing a glitch on the
power-supply rail. These devices operate from +9V to
+72V and provide the simplest hot-swap solution by
eliminating all external components except the external
P-channel MOSFET.
The MAX5902/MAX5903 limit the inrush current to the
load and provide a circuit breaker function for overcur-
rent protection. During startup the circuit breaker func-
tion is disabled and the MAX5902/MAX5903 limit the
inrush current by gradually turning on the external
MOSFET. Once the external MOSFET is fully enhanced,
the circuit breaker function is enabled and the
MAX5902/MAX5903 provide overcurrent protection by
monitoring the voltage drop across the external MOS-
FET’s on-resistance.
The MAX5902/MAX5903 include an undervoltage lock-
out (UVLO) function, ON/OFF control input and a
power-good status output,
PGOOD
(MAX5902) or
PGOOD (MAX5903). A built in thermal shutdown fea-
ture is also included to protect the external MOSFET in
case of overheating.
The MAX5902/MAX5903 offer latched or auto-retry fault
management and are available with 300mV, 400mV or
500mV circuit breaker thresholds. Both the MAX5902
and MAX5903 are available in a small SOT23 package,
and are specified for the extended -40°C to +85°C tem-
perature range. For specific ordering information refer
to the selector guide at the end of the data sheet.
o
Wide +9V to +72V Operation
o
Requires No External Sense Resistor
o
Drives External P-Channel MOSFET
o
Limits Inrush Current
o
Circuit Breaker Function
o
Less than 2mA Quiescent Current
o
ON/OFF Input Permits Load Power-Supply
Control and Sequencing
o
Adjustable Undervoltage Lockout
o
Power-Good Output with +72V Rating
o
Latching or Automatic Retry Fault Management
o
Thermal Shutdown Helps Protect the External
MOSFET
o
Space-Saving SOT23-6 Package
Features
Ordering Information
PART
MAX5902_
_EUT*
MAX5903_
_EUT*
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
6-SOT23
6-SOT23
*For specific part numbers see Selector Guide at end of data
sheet.
Applications
Network Routers
Network Switches
Base Station Line
Cards
Servers
RAID
Industrial Systems
Typical Operating Circuits
50W ISOLATED
POWER SUPPLY
IRFR5410
HOT-SWAP CONTROLLER
V
IN
(+)
LUCENT
JW050A1
BACKPLANE CIRCUIT CARD
+48V
Pin Configuration
V
S
MAX5902
GATE
DRAIN
PGOOD
TOP VIEW
V
S
1
6
ON/OFF
GND
ON/OFF
GND
ON/OFF
V
IN
(-)
DRAIN
2
MAX5902
MAX5903
5
PGOOD (PGOOD)
GATE
3
4
GND
Typical Operating Circuits continued at end of data sheet.
SOT23-6
( ) ARE FOR MAX5903 ONLY.
Simple Swapper is a trademark of Maxim Integrated Products Inc.
1
________________________________________________________________
Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
+72V SOT23 Simple Swapper Hot-Swap
Controllers
MAX5902/MAX5903
ABSOLUTE MAXIMUM RATINGS
Terminal Voltage (with respect to GND unless otherwise noted)
V
S
, DRAIN, PGOOD,
PGOOD
................................-0.3V to +76V
ON/OFF ....................................................................-0.3V to +4V
GATE to V
S
............................................................-12V to +0.3V
Current into any Pin ............................................................±3mA
Continuous Power Dissipation at T
A
= +70°C
6-Pin SOT23 (derate 9.1mW/°C above +70°C)..........727mW
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature .............................................................Note 1
Note 1:
This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device
can be exposed to during board level solder attach and rework. This limit permits only the use of solder profiles recom-
mended in the industry standard specification, JEDEC 020A, paragraph 7.6, Table 3 for IR/VPR and convection reflow.
Preheating is required. Hand or wave soldering is not allowed.
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
(V
S
= +9V to +72V, GND = 0, ON/OFF open circuit, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
S
= +48V
and T
A
= +25°C.) (Notes 2, 3)
PARAMETER
Supply Voltage
Supply Current
External Gate Drive
Load Voltage Slew Rate
Magnitude
Default Undervoltage Lockout
Undervoltage Lockout
Hysteresis
ON/OFF Pin Input Resistance
DRAIN to GND Resistance
DRAIN to V
S
Resistance
ON/OFF Reference Threshold
ON/OFF Hysteresis
Start Delay (Note 4)
ON/OFF Off Delay (Note 5)
Circuit Breaker Threshold
t
ON
t
OFF
V
CB
V
S
- V
GATE
< 1V
MAX590_ _AEUT
V
S
- V
DRAIN
(V
S
- V
DRAIN
) > V
CB
until (V
S
- V
GATE
)
< 1V, 200mV
overdrive step
MAX590_ _BEUT
MAX590_ _CEUT
C
GATE
= 1nF
C
GATE
= 4.7nF
C
GATE
= 10nF
80
Circuit Breaker Delay (Note 6)
t
CB
80
5
200
280
400
R
ON/OFF
R
DGND
R
DS
V
ON/OFF
V
ON/OFF
Increasing
1.14
19
SYMBOL
V
S
I
GND
V
GS
SR
V
UVLO
CONDITIONS
Measured out of GND, PGOOD or
PGOOD
open circuit, DRAIN = V
S
V
S
- V
GATE
| dV
DRAIN
/dt |
C
L
= 10µF
V
S
increasing
V
S
= +36V to +72V
V
S
= +9V
V
S
= +36V to +72V
V
S
= +9V
9
8
5
3
28.5
MIN
9
TYP
MAX
72
2
11
18
11
34.5
UNITS
V
mA
V
V/ms
V
V
52
kΩ
kΩ
kΩ
1.38
280
18
460
540
660
6.5
11
17
280
0.6
ms
V
µs
mV
V
mV
ms
ms
1
10
8.5
9
6
31.5
3.5
32
900
650
1.26
140
150
10
300
400
500
2
4
7
150
0.3
Restart Delay (Note 4)
Power Good Output Low Voltage
t
RS
V
OL
After circuit breaker event,
MAX590_ A_EUT only
I
OL
= 1mA
2
_______________________________________________________________________________________
+72V SOT23 Simple Swapper Hot-Swap
Controllers
ELECTRICAL CHARACTERISTICS (continued)
(V
S
= +9V to +72V, GND = 0, ON/OFF open circuit, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
S
= +48V
and T
A
= +25°C.) (Notes 2, 3)
PARAMETER
Power-Good Output Open-Drain
Leakage Current
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
SYMBOL
I
OH
T
SD
T
HY
CONDITIONS
V
PGOOD
= 72V (MAX5902)
V
PGOOD
= 72V (MAX5903)
Junction temperature
+125
15
MIN
TYP
MAX
10
UNITS
µA
°C
°C
MAX5902/MAX5903
Note 2:
All currents into device pins are positive, all currents out of device pins are negative, and all voltages are referenced to
GND, unless otherwise noted.
Note 3:
All specifications are 100% tested at T
A
= +25°C, unless otherwise noted. Specifications over -40°C to +85°C are guaran-
teed by characterization.
Note 4:
This is the delay time from a valid on condition until V
GS
begins rising. Valid on conditions are: the device is not in undervolt-
age lockout; ON/OFF is not driven low; and the device is not in thermal shutdown.
Note 5:
This is the delay from a valid low on ON/OFF until V
GS
falls. Pulses on ON/OFF less than t
OFF
are ignored, offering glitch
immunity.
Note 6:
Guaranteed by characterization, not production tested. C
GATE
is a capacitor from GATE to V
S
.
Typical Operating Characteristics
(V
S
= +48V, GND = 0, and T
A
= +25°C, unless otherwise noted. See Figure 2 for test circuits.)
SUPPLY CURRENT
vs. INPUT VOLTAGE
MAX5902 toc01
SUPPLY CURRENT
vs. TEMPERATURE
MAX5902 toc02
V
UVLO
THRESHOLD
vs. TEMPERATURE
34
33
LOCKOUT VOLTAGE (V)
32
31
30
29
28
27
26
DECREASING V
IN
INCREASING V
IN
MAX5902 toc03
1.2
1.2
V
IN
= +70V
35
1.1
SUPPLY CURRENT (mA)
1.1
SUPPLY CURRENT (mA)
1.0
1.0
V
IN
= +48V
0.9
0.9
V
IN
= +12V
0.8
0.8
0.7
0
15
30
45
60
75
INPUT VOLTAGE (V)
0.7
-40
-15
10
35
60
85
TEMPERATURE (°C)
25
-40
-15
10
35
60
85
TEMPERATURE (°C)
_______________________________________________________________________________________
3
+72V SOT23 Simple Swapper Hot-Swap
Controllers
MAX5902/MAX5903
Typical Operating Characteristics (continued)
(V
S
= +48V, GND = 0, and T
A
= +25°C, unless otherwise noted. See Figure 2 for test circuits.)
GATE DRIVE VOLTAGE
vs. INPUT VOLTAGE
MAX5902 toc04
RETRY TIMEOUT
vs. TEMPERATURE
MAX5902 toc05
TURN-ON WAVEFORMS
R
L
= 60Ω, C
L
= 100µF
A
0
B
0
15
225
200
TIMEOUT PERIOD (ms)
175
150
MAX5902 toc06
13
GATE DRIVE (V)
11
9
C
125
100
75
D
0
t = 20ms/div
0
7
5
0
15
30
45
60
75
INPUT VOLTAGE (V)
-40
-15
10
35
60
85
TEMPERATURE (°C)
A : V
OUT
, 50V/div
B : I
IN
, 1A/div
C : V
GATE
, 50V/div
D : V
IN
, 50V/div
TURN-ON WAVEFORMS
R
L
= OPEN, C
L
= 100µF
MAX5902 toc07
TURN-ON WAVEFORMS
R
L
= 60Ω, C
L
= 10µF
MAX5902 toc08
A
0
0
TURN-ON WAVEFORMS
R
L
= 60Ω, C
L
= 100µF
MAX5902 toc09
A
0
A
B
0
B
0
B
0
C
0
t = 2ms/div
A : V
OUT
, 50V/div
B : I
IN
, 1A/div
C : V
GATE
, 20V/div
C
0
t = 2ms/div
A : V
OUT
, 50V/div
B : I
IN
, 0.5A/div
C : V
GATE
, 20V/div
C
0
t = 2ms/div
A : V
OUT
, 50V/div
B : I
IN
, 1A/div
C : V
GATE
, 20V/div
CIRCUIT BREAKER EVENT
V
OVERDRIVE
= 20mV, C
GATE
= 1000pF
0
A
CIRCUIT BREAKER EVENT
V
OVERDRIVE
= 200mV, C
GATE
= 1000pF
MAX5902 toc11
MAX5902 toc10
0
A
B
0
0
B
0
C
0
C
4
_______________________________________________________________________________________
t = 1µs/div
A : V
DS
, 0.5V/div
B : V
GS
, 10V/div
C : V
PGOOD
TO V
S
, 50V/div
t = 1µs/div
A : V
DS
, 0.5V/div
B : V
GS
, 10V/div
C : V
PGOOD
TO V
S
, 50V/div
+72V SOT23 Simple Swapper Hot-Swap
Controllers
Pin Description
PIN
MAX5902
1
2
3
4
5
—
MAX5903
1
2
3
4
—
5
NAME
V
S
DRAIN
GATE
GND
PGOOD
PGOOD
FUNCTION
Positive Supply Voltage Input and External P-Channel MOSFET Source Connection
Drain Sense Input for External P-Channel MOSFET. Connect DRAIN as close as
possible to the MOSFET’s drain and use wide circuit traces to assure good thermal
coupling between the MAX5902/MAX5903 and the MOSFET. See
Layout Guidelines.
Gate Drive Output for External P-Channel MOSFET
Ground Connection
Power Good Output.
PGOOD
is an N-channel, open-drain, active-low output,
referenced to GND.
Power Good Output. PGOOD is an N-channel, open-drain, active-high output,
referenced to GND.
ON/OFF Control Input. ON/OFF is referenced to GND. Drive ON/OFF above 1.38V or
leave unconnected to enable the device. Drive ON/OFF below 1V to disable the device.
ON/OFF is also used to adjust the UVLO threshold. Internally clamped to nominally 3V
through a 1kΩ resistor. (See Figure 1.) (See
Undervoltage Lockout
in the
Applications
section of this data sheet.)
MAX5902/MAX5903
6
6
ON/OFF
Detailed Description
The MAX5902/MAX5903 are integrated hot-swap con-
troller ICs contained in 6-pin SOT23 packages. They
allow a board to be safely hot-plugged into a live back-
plane without causing a glitch on the power-supply rail.
They are well suited for +48V power systems allowing
cost-effective, simple, and compact design. The
MAX5902/MAX5903 operate from +9V to +72V to cover
a wide range of end equipment hot-swap needs. They
require only an external P-channel power MOSFET to
provide hot-swap control. Figure 1 shows a functional
block diagram of the MAX5902/MAX5903.
The MAX5902/MAX5903 controls an external P-channel
power MOSFET placed in the positive power-supply
pathway. When power is first applied, the MAX5902/
MAX5903 keep the MOSFET turned off. The
MAX5902/MAX5903 hold the MOSFET off indefinitely if
ON/OFF is held low, if the supply voltage is below the
undervoltage lockout level, or if the die temperature
exceeds +125°C. If none of these conditions exist for
150ms (typ), the MAX5902/MAX5903 begin to gradually
turn on the MOSFET. During this turn-on phase, the
MAX5902/MAX5903 slowly enhance the MOSFET,
allowing the voltage on the load, i.e. the drain of the
MOSFET, to rise at a rate of 9V/ms (typ). The inrush cur-
rent to the load is thus limited to a level proportional to
the load capacitance, and the constant slew rate. After
the MOSFET is fully enhanced, and the load voltage is
MAX5902
MAX5903
V
S
*
828kΩ
ON/OFF
1kΩ
*
34.5kΩ
3V
CONTROL
LOGIC
PGOOD
(PGOOD)
GND
GND
*900kΩ
*650kΩ
GND
DRAIN
GATE
( ) ARE FOR THE MAX5903 ONLY
* RELATIVE TOLERANCE
±1%,
ABSOLUTE TOLERANCE
±50%
(TYP)
Figure 1. Functional Block Diagram
settled to its final value, the MAX5902A/ MAX5903A and
MAX5902L/MAX5903L monitor the voltage drop across
the MOSFET. If the voltage drop exceeds the circuit
breaker threshold the MAX5902A/MAX5903A and
MAX5902L/MAX5903L turn off the MOSFET, discon-
_______________________________________________________________________________________
5
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