MAX5901ACEUT [MAXIM]
Analog IC ; 模拟IC\n
| 型号： | MAX5901ACEUT |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Analog IC
|
| 文件： | 总11页 (文件大小：266K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-1988; Rev 0; 3/01
-100V SOT23 Simple Swapper Hot-Swap
Controllers
General Description
Features
The MAX5900/MAX5901 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
-100V and provide the simplest hot-swap solution by
eliminating all external components except an external
N-channel MOSFET.
o Wide -9V to -100V Operation
o Requires No External Sense Resistor
o Drives External N-Channel MOSFET
o Limits Inrush Current
o Circuit Breaker Function
The MAX5900/MAX5901 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 MAX5900/MAX5901 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
MAX5900/MAX5901 provide overcurrent protection by
monitoring the voltage drop across the external MOS-
FET’s on-resistance.
o Less than 1mA Quiescent Current
o ON/OFF Input Permits Load Power-Supply
Control and Sequencing
o Adjustable Undervoltage Lockout
o Power-Good Output with 100V Rating
o Latching or Automatic Retry Fault Management
o Thermal Shutdown Helps Protect the External
The MAX5900/MAX5901 include an undervoltage lock-
out (UVLO) function, ON/OFF control input, and a
power-good status output, PGOOD (MAX5900) or
PGOOD (MAX5901). A built-in thermal shutdown fea-
ture is also included to protect the external MOSFET in
case of overheating.
MOSFET
o Space-Saving SOT23-6 Package
Ordering Information
The MAX5900/MAX5901 offer latched or auto-retry fault
management and are available with 200mV, 300mV or
400mV circuit breaker thresholds. Both the MAX5900
and MAX5901 are available in small SOT23 packages,
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.
PART
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
6 SOT23
MAX5900_ _EUT*
MAX5901_ _EUT*
6 SOT23
*For specific part numbers see Selector Guide at end of data
sheet.
Applications
Pin Configuration
Telecom Line Cards Network Switches
Network Routers
Servers
TOP VIEW
Base Station Line
Cards
V
1
2
3
6
5
4
ON/OFF
EE
MAX5900
MAX5901
DRAIN
GATE
PGOOD (PGOOD)
GND
Typical Operating Circuits
50W ISOLATED
POWER SUPPLY
BACKPLANE CIRCUIT CARD
GND
HOT-SWAP CONTROLLER
V +
I
SOT23-6
( ) ARE FOR MAX5901 ONLY.
LUCENT
JW050A1
MAX5900
ON/OFF
GND
PGOOD
DRAIN
GATE
ON/OFF
V
V -
I
EE
Typical Operating Circuits continued at end of data sheet.
-48V
IRF540NS
Simple Swapper is a trademark of Maxim Integrated Products Inc.
FUSE
________________________________________________________________ Maxim Integrated Products
1
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.
-100V SOT23 Simple Swapper Hot-Swap
Controllers
ABSOLUTE MAXIMUM RATINGS
Terminal Voltage (with respect to GND unless otherwise noted)
Continuous Power Dissipation at T = +70°C
A
V , DRAIN, PGOOD, PGOOD ............................-120V to +0.3V
EE
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
ON/OFF to V .........................................................-0.3V to +4V
EE
GATE to V ...........................................................-0.3V to +12V
EE
Current into any Pin ............................................................ 3mA
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 = -9V to -100V, GND = 0, ON/OFF open circuit, T = -40°C to +85°C, unless otherwise noted. Typical values are at V = -48V
EE
A
EE
and T = +25°C.) (Notes 2, 3)
A
PARAMETER
Supply Voltage
SYMBOL
CONDITIONS
MIN
TYP
MAX
-9
UNITS
V
V
-100
EE
Supply Current
I
Measured at GND
0.5
9.5
10
7
1.3
mA
GND
V
V
V
= -36V to -72V
= -100V
7.5
8
11.6
11.6
EE
EE
EE
External Gate Drive
V
V
- V
EE
V
GS
GATE
= -9V
6
Load Voltage Slew Rate
Magnitude
SR
| dV
/dt |, C
= 10µF, V = -9V to -36V
4.5
10
17
V/ms
DRAIN
LOAD
EE
Default UVLO
V
|VEE| increasing
-34.5
-31.5
3.5
-28.5
V
UVLO
UVLO Hysteresis
V
ON/OFF Input Resistance
R
20
32
50
kΩ
kΩ
ON/OFF
DRAIN to V Resistance
EE
R
466
DVEE
ON/OFF Reference
Threshold
V
(V V ) increasing
ON/OFF - EE
1.14
1.26
1.38
V
ON/OFF
ON/OFF Hysteresis
140
300
20
mV
ms
ms
Start Delay (Note 4)
t
150
9
500
32
ON
ON/OFF Off Delay (Note 5)
t
V
V
- V < 1V
GATE EE
OFF
MAX590_ _AEUT
MAX590_ _BEUT
MAX590_ _CEUT
170
265
365
200
300
400
1.5
2.5
4
240
345
455
3
Circuit Breaker
Threshold
V
t
- V
EE
mV
CB
DRAIN
C
C
C
= 1nF
GATE
GATE
GATE
(V
until (V
200mV overdrive step
- V ) > V
EE CB
DRAIN
Circuit Breaker Delay
(Note 6)
- V ) < 1V,
EE
= 4.7nF
= 10nF
4.5
6
µs
GATE
CB
Restart Delay (Note 4)
t
After circuit breaker event, MAX590_ A_EUT only
150
300
500
ms
RS
2
_______________________________________________________________________________________
-100V SOT23 Simple Swapper Hot-Swap
Controllers
ELECTRICAL CHARACTERISTICS (continued)
(V = -9V to -100V, GND = 0, ON/OFF open circuit, T = -40°C to +85°C, unless otherwise noted. Typical values are at V = -48V
EE
A
EE
and T = +25°C.) (Notes 2, 3)
A
PARAMETER
SYMBOL
CONDITIONS
- V ; MAX590_A,
MIN
TYP
MAX
UNITS
PGOOD (PGOOD)
Assertion Threshold
(Note 7)
V
DRAIN
EE
V
V
0.75 ✕ V
mV
PG
CB
MAX590_L only
PGOOD (PGOOD)
Output Low Voltage
MAX5900 V
MAX5901 V
- V , I = 1mA;
PGOOD EE OL
0.6
0.2
1.65
10
V
OL
- V , I = 1mA
EE OL
PGOOD
Power-Good Output Open-
Drain Leakage Current
V
V
- V = 100V (MAX5900)
PGOOD EE
I
µA
°C
°C
OH
- V = 100V (MAX5901)
EE
PGOOD
Thermal Shutdown
Temperature
T
SD
T
HY
Junction temperature
+125
15
Thermal Shutdown
Hysteresis
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 = +25°C. Specifications over -40°C to +85°C are guaranteed by characterization.
A
Note 4: This is the delay time from a valid on condition until V begins rising. Valid on conditions are: the device is not in undervolt-
GS
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 falls. Pulses on ON/OFF less than t
are ignored, offering glitch
GS
OFF
immunity.
Note 6: Guaranteed by design, not production tested.
Note 7: For a detailed description see the Power-Good Output section of the data sheet.
Typical Operating Characteristics
(V = -48V, GND = 0, and T = +25°C, unless otherwise noted. See Figure 6 for test circuits.)
EE
A
DEFAULT UNDERVOLTAGE LOCKOUT
SUPPLY CURRENT
vs.INPUT VOLTAGE
SUPPLY CURRENT
vs. TEMPERATURE
vs. TEMPERATURE
-25.5
-26.5
-27.5
-28.5
-29.5
-30.5
-31.5
-32.5
-33.5
-34.5
-35.5
-36.5
-37.5
0.90
0.85
0.80
0.75
0.70
0.65
0.60
0.55
1.1
100kΩ FROM ON/OFF TO GND
V
= -72V
DECREASING |V
|
EE
EE
1.0
0.9
0.8
0.7
0.6
0.5
V
EE
= -48V
= -12V
V
EE
INCREASING |V
|
EE
125
-50 -25
0
25
50
75 100
-100
-80
-60
-40
-20
0
-50 -25
0
25
50
75 100 125
TEMPERATURE (°C)
INPUT VOLTAGE (V)
TEMPERATURE (°C)
_______________________________________________________________________________________
3
-100V SOT23 Simple Swapper Hot-Swap
Controllers
Typical Operating Characteristics (continued)
(V = -48V, GND = 0, and T = +25°C, unless otherwise noted. See Figure 6 for test circuits.)
EE
A
GATE DRIVE VOLTAGE
vs. INPUT VOLTAGE
RESTART DELAY
vs. TEMPERATURE
STARTUP WAVEFORMS
R = 90Ω, C = 100µF
L
L
11.0
450
400
350
300
250
200
150
10.5
10.0
9.5
9.0
8.5
8.0
7.5
7.0
A
0
0
B
0
C
0
D
40ms/div
-100
-80
-60
-40
-20
0
-50 -25
0
25
50
75 100 125
A: V , 5V/div
IN
C: V , 50V/div
EE
GS
INPUT VOLTAGE (V)
TEMPERATURE (°C)
B: I , 1A/div
D: V
, 40V/div
DRAIN
STARTUP WAVEFORMS
STARTUP WAVEFORMS
STARTUP WAVEFORMS
R = OPEN, C = 10µF
R = 40Ω, C = 10µF
L
L
R = 40Ω, C = 100µF
L
L
L
L
A
A
A
0
0
0
0
B
0
0
B
B
0
C
0
C
0
C
0
D
0
D
0
D
5ms/div
5ms/div
5ms/div
A: V , 10V/div
IN
GS
A: V , 10V/div
GS
IN
C:V , 50V/div
OUT
D: PGOOD, 50V/div
A: V , 10V/div
GS
IN
C:V , 50V/div
OUT
D: PGOOD, 50V/div
B: I , 200mA/div
B: I , 1A/div
B: I , 1A/div
C:V , 50V/div
OUT
D: PGOOD, 50V/div
CIRCUIT BREAKER EVENT
= 1000pF, V = 200mV)
CIRCUIT BREAKER EVENT
= 1000pF, V = 20mV)
(C
(C
GATE
OVERDRIVE
SLEW RATE vs. V
GATE
OVERDRIVE
EE
12
T
A
= +120°C
11
10
9
A
0
A
0
B
0
B
0
T
A
= +25°C
0
8
C
0
C
T
A
= -40°C
7
6
2µs/div
2µs/div
-100
-80
-60
-40
-20
0
A: PGOOD, 50V/div
A: PGOOD, 50V/div
DS
C:V , 10V/div
GS
B:V , 0.5V/div
B:V , 0.5V/div
DS
V
(V)
EE
C:V , 10V/div
GS
4
_______________________________________________________________________________________
-100V SOT23 Simple Swapper Hot-Swap
Controllers
Pin Description
PIN
NAME
FUNCTION
MAX5900
MAX5901
Negative Supply Voltage Input and External N-Channel MOSFET Source
Connection
1
1
V
EE
Drain Sense Input for External N-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 MAX5900/MAX5901 and the MOSFET. See Layout
Guidelines.
2
2
DRAIN
3
4
3
4
GATE
GND
Gate Drive Output for External N-Channel MOSFET
Ground Connection
Power-Good Output. PGOOD is an N-channel, open-drain, active-high output,
5
—
PGOOD
referenced to V
.
EE
Power-Good Output. PGOOD is an N-channel, open-drain, active-low output,
referenced to V
—
5
PGOOD
.
EE
ON/OFF Control Input. ON/OFF is referenced to V . Drive ON/OFF above 1.38V or
EE
leave unconnected to enable the device. Drive ON/OFF below 1V to disable the
device. ON/OFF is also used to adjust the undervoltage lockout (UVLO) threshold. See
Undervoltage Lockout in the Applications section of this data sheet. Internally clamped
to nominally 3V through a 1kΩ resistor (see Figure 1).
6
6
ON/OFF
Detailed Description
The MAX5900/MAX5901 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 telecom power systems
allowing cost-effective, simple, and compact design.
The MAX5900/MAX5901 operate from -9V to -100V to
cover the standard telecom voltage range, and to serve
more generalized applications. These devices require
only an external N-channel power MOSFET to provide
hot-swap control. Figure 1 shows a functional diagram
of the MAX5900/MAX5901.
MAX5900
MAX5901
GND
828kΩ*
ON/OFF
CONTROL
LOGIC
1kΩ*
34.5kΩ*
PGOOD
(PGOOD)
3V
N
The MAX5900/MAX5901 control an external N-channel
power MOSFET placed in the negative power-supply
pathway. When power is first applied, the MAX5900/
MAX5901 keep the MOSFET turned off. The
MAX5900/MAX5901 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
300ms (typ), the MAX5900/MAX5901 begin to gradually
turn on the MOSFET. During this turn-on phase, the
MAX5900/MAX5901 slowly enhance the MOSFET,
allowing the voltage on the load, i.e. the drain of the
V
EE
V
EE
V
EE
466kΩ*
GATE
( ) ARE FOR THE MAX5901 ONLY
* RELATIVE TOLERANCE 1%, ABSOLUTE TOLERANCE 20% TYPICAL
DRAIN
Figure 1. Functional Diagram
_______________________________________________________________________________________
5
-100V SOT23 Simple Swapper Hot-Swap
Controllers
MOSFET, to fall no faster than 10V/ms (typ). The inrush
current to the load is thus limited to a level proportional
to the load capacitance, and the constant load voltage
slew rate. After the MOSFET is fully enhanced, and the
load voltage is settled to its final value, the MAX5900A/
MAX5901A and MAX5900L/MAX5901L monitor the volt-
fully enhanced. Three threshold voltage options are
available—200mV, 300mV, and 400mV. One version is
available with no circuit breaker function. Circuit break-
er fault management for the MAX5900/MAX5901 is
offered with two different configurations—latched and
automatic retry.
age drop from the MOSFET’s drain-to-source (V ). If
DS
Latched Circuit Breaker
After a circuit breaker trip event, the latched
versions (MAX5900L/MAX5901L) drive GATE to
the voltage drop exceeds 75% of the circuit breaker
threshold the MAX5900A/MAX5901A or MAX5900L/
MAX5901L turn off the MOSFET, disconnecting the
load immediately. Because the circuit breaker function
is not activated until the MOSFET is fully enhanced, it
takes approximately 10ms for the MAX5900A/
MAX5901A or MAX5900L/MAX5901L to react to an out-
put short circuit at startup. If no circuit breaker fault
exists, the power-good output is asserted. Then, if any
of four conditions exist, the power-good output
deasserts and the MOSFET is turned off . The four con-
ditions are: the voltage across the MOSFET exceeds
the circuit breaker threshold; the supply voltage magni-
tude falls below the undervoltage lockout level; the die
temperature exceeds +125°C; or ON/OFF is forced low.
After a circuit breaker fault, the MAX5900L/MAX5901L
keep the MOSFET off until the power is cycled, or the
part is reset by toggling ON/OFF low for at least 20ms
(typ). After a circuit breaker fault, the MAX5900A/
MAX5901A automatically restart in 300ms (typ). All ver-
sions automatically restart after a thermal fault, or an
undervoltage shutdown, if the fault condition goes away
for at least 300ms (typ).
V
, turning off the external MOSFET, and PGOOD
EE
(PGOOD) is deasserted. A latched-off condition
needs to be reset by toggling ON/OFF low for at
least 20ms, or by cycling the power supply, V
.
EE
Automatic Retry Circuit Breaker
After a circuit breaker trip event the automatic retry
versions (MAX5900A/MAX5901A) drive GATE to V
,
EE
turning off the external MOSFET, and PGOOD
(PGOOD) is deasserted. If the start conditions are met
for a full 300ms (t ) the start sequence is initiated. The
RS
start conditions are: the device is not in UVLO; ON/OFF
is not driven low; and the device is not in thermal shut-
down.
No Circuit Breaker
For the versions without a circuit breaker, MAX5900N
(MAX5901N), PGOOD (PGOOD) is asserted when the
MOSFET is fully enhanced. Once powered up, the
MAX5900N/MAX5901N ignore the MOSFET drain-to-
source voltage (V ) for applications where a circuit
DS
breaker function is not desired.
ON/OFF offers external control of the MAX5900/
MAX5901, facilitating power-supply sequencing, and
may also be used to change the undervoltage lockout
level. Undervoltage lockout keeps the external MOSFET
switched off as long as the magnitude of the input volt-
age is below the desired level.
Applications Information
ON/OFF Control Input
The ON/OFF control input provides three hot-swap
functions: external ON/OFF control; setting of the UVLO
level; and resetting after a circuit breaker event has
caused the MAX5900L/MAX5901L to turn off the exter-
A power-good output, PGOOD (MAX5900) or PGOOD
(MAX5901), asserts when the external MOSFET is fully
enhanced and the drain-source voltage is at least 25%
below the circuit breaker threshold. PGOOD and
nal MOSFET. Pulling ON/OFF to V for at least 20ms
EE
(t
) forces the MAX5900/MAX5901 to turn off the
OFF
external MOSFET (see Figure 2 for a circuit example).
To reset the MAX5900L/MAX5901L after a circuit break-
PGOOD are open-drain outputs referenced to V , and
EE
can withstand up to 100V above V
.
EE
er event, toggle ON/OFF to V for at least 20ms (t
).
EE
OFF
A thermal shutdown feature protects the external MOS-
FET by turning it off if the die temperature of the
MAX5900/MAX5901 exceeds +125°C. The MAX5900/
MAX5901 must be in good thermal contact with the
external MOSFET. See Layout Guidelines in the Appli-
cations section of the data sheet.
ON/OFF can be used to sequence power supplies.
Connecting a capacitor from ON/OFF to V will delay
EE
the rise of ON/OFF proportional to the capacitance and
input impedance of ON/OFF, typically 32kΩ (Figure 3).
A circuit breaker function monitors the voltage across
the external MOSFET, V , and turns off the MOSFET if
DS
V
exceeds the circuit breaker threshold, V . The
circuit breaker function is enabled after the MOSFET is
DS
CB
6
_______________________________________________________________________________________
-100V SOT23 Simple Swapper Hot-Swap
Controllers
Thermal Shutdown
HOT-SWAP CONTROLLER
A thermal shutdown feature helps protect the external
MOSFET. If the die temperature of the MAX5900/
GND
MAX5900
MAX5901
MAX5901 exceeds +125°C, the MOSFET is turned off.
OPTIONAL
R2
47kΩ
For accurate performance the MAX5900/MAX5901
ON/OFF
GND
must be in close thermal contact with the external MOS-
FET. See Layout Guidelines for information. Due to the
low power dissipation of the MAX5900/MAX5901, the
junction temperature will typically be within a few
degrees of the MOSFET. All versions of the MAX5900/
MAX5901 automatically restart from a temperature fault
when the junction temperature drops below +110°C.
ON/OFF
V
EE
R1
3kΩ
DGND
-48V
Figure 2. Programmed -20V Lockout, with Optional Optocoupler
On/Off Control
Undervoltage Lockout
The MAX5900/MAX5901 turn off the external MOSFET if
the magnitude of the input voltage is below the level set
HOT-SWAP CONTROLLER #1
by ON/OFF for longer than 20ms (t
). If ON/OFF is
OFF
left unconnected, the lockout voltage (V
) defaults
UVLO
GND
MAX5900
MAX5901
to -31.5V. V
may also be set to any value within
UVLO
GND
ON/OFF
the power-supply range by using external resistors. To
set the lockout voltage to a value between -9V and
-100V use a resistor-divider connected between GND
C
V
EE
and V , with the center node of the divider connected
EE
to ON/OFF. For example, use a 3kΩ resistor (R1 in
Figure 2) from ON/OFF to V and calculate the other
EE
resistor, R2, using:
HOT-SWAP CONTROLLER #2
|V
1.26
|
MAX5900
MAX5901
UVLO
R2 = R1 ×
−1
GND
ON/OFF
where V
ON/OFF
is the desired lockout voltage, and
UVLO
2C
V
EE
V
is the ON/OFF reference threshold specified in
the Electrical Characteristics table (typically 1.26V).
V
EE
Figure 2 shows an example circuit with V set for
UVLO
-20V. To defeat the UVLO simply connect a single
100kΩ resistor between ON/OFF and GND, as shown in
Figure 4.
Figure 3. Power-Supply Sequencing
Turn-On and Turn-Off Delays
After power is applied, or ON/OFF is released, there is
HOT-SWAP CONTROLLER
a 300ms delay (t ) before the gate ramp is started.
ON
This delay is also the automatic restart time delay.
GND
MAX5900
MAX5901
In the event of a circuit breaker condition or an over-
temperature fault condition, the turn-off delay is less
than 2µs. An undervoltage condition must exist for at
100kΩ
GND
least 20ms (t
) before the MAX5900/MAX5901 turn
OFF
ON/OFF
off the external MOSFET. ON/OFF must be held low for
at least 20ms (t ) before the MAX5900/MAX5901 turn
V
EE
OFF
off the external MOSFET. Turn-off delay minimizes spu-
rious shutdowns due to noisy signals or momentary
voltage spikes, as well as preventing accidental reset-
ting of the circuit breaker latch (MAX5900L/MAX5901L).
-48V
Figure 4. Defeating Undervoltage Lockout
_______________________________________________________________________________________
7
-100V SOT23 Simple Swapper Hot-Swap
Controllers
parameters. Using this method to choose a circuit
Power-Good Output
The power-good output, PGOOD (PGOOD), is open-
drain and asserts when the external MOSFET is fully
breaker threshold allows the circuit to operate under
worst-case conditions without causing a circuit
breaker fault, but the circuit breaker function will still
operate if a short-circuit or gross overcurrent condition
occurs. See Table 1 for MOSFET suggestions. The
MAX5900N/MAX5901N have no circuit breaker func-
tion. For these parts choose an external MOSFET that
meets the load requirements.
enhanced and V
is less than V
(75% of the circuit
PG
DS
breaker threshold, V ). For versions without the circuit
CB
breaker function (MAX5900N/MAX5901N), PGOOD
(PGOOD) asserts when the external MOSFET is fully
enhanced.
PGOOD (PGOOD) deasserts within 2µs when a circuit
breaker event occurs or if the die temperature exceeds
Determining Inrush Current
Determining a circuit’s inrush current is necessary to
help choose the proper MOSFET. The MAX5900/
MAX5901 regulate the inrush current by means of con-
trolling the load voltage slew rate, but inrush current is
also a function of load capacitance. Determine inrush
current using:
+125°C. PGOOD (PGOOD) deasserts if |V | < |V
|
EE
UVLO
for longer than 20ms or ON/OFF is held low for longer
than 20ms.
The MAX5900 PGOOD is active-low and the MAX5901
PGOOD is active-high. Both are open-drain N-channel
MOSFETs with their sources connected to V , and can
EE
withstand up to 100V.
dV
dt
Selecting a Circuit Breaker Threshold
The MAX5900A/MAX5901A and the MAX5900L/
MAX5901L offer a circuit breaker function to protect the
external MOSFET and the load from the potentially
damaging effects of excessive current. As load current
I = C
= C × SR
where C is the load capacitance, and SR is the
MAX5900/MAX5901 Load Voltage Slew Rate Magnitude
from the Electrical Characteristics table. For example,
assuming a load capacitance of 100µF, and using the
typical value of 10V/ms for the slew rate, the inrush cur-
rent is 1A typical.
flows through the external MOSFET, a voltage, V , is
DS
generated from drain to source due to the MOSFET’s
on-resistance, R
. The MAX5900A/MAX5901A
DS(ON)
and MAX5900L/MAX5901L monitor V when the exter-
DS
If the maximum possible Load Voltage Slew Rate is
used, the maximum inrush current calculates to 1.7A.
Choose a MOSFET with a maximum pulsed current
specification that exceeds the maximum inrush current.
nal MOSFET is fully enhanced. If V
exceeds the cir-
DS
cuit breaker threshold, the external MOSFET is turned
off and PGOOD (PGOOD) is deasserted.
To accommodate different MOSFETs and different load
currents, the MAX5900/MAX5901 are available with cir-
cuit breaker threshold voltages of 200mV, 300mV, and
400mV.
Suggested External MOSFETs
The circuit breaker function is intended to disconnect
the load if a gross overcurrent or short-circuit condition
occurs. For calculating the circuit breaker threshold use
SUGGESTED
MAXIMUM
(A)
SUGGESTED
MAXIM PART
EXTERNAL
MOSFET
I
LOAD
the MOSFET’s R
at the worst possible operating con-
ON
dition, and add a 25% overcurrent margin to the maxi-
mum circuit current. For instance, if a MOSFET has an
0.25
IRFL110
IRFL4310
IRFR3910
IRF540NS
IRF1310NS
IRF1310NS
MAX590_ _CEUT
MAX590_ _BEUT
MAX590_ _CEUT
MAX590_ _BEUT
MAX590_ _BEUT
MAX590_ _CEUT
0.5
R
of 0.06Ω at T = +25°C, and a normalized on-
ON
A
resistance factor of 1.75 at T = +130°C (from the
1
A
MOSFET data sheet), the R
used for calculation is
ON
2
the product of these two numbers, or (0.06Ω) x (1.75) =
0.105Ω. Then, if the maximum current is expected to be
2A, using a 25% margin, the current for calculation is
(2A) x (1.25) = 2.5A. The resulting minimum circuit
breaker threshold is then the product of these
two results, or (0.105Ω) x (2.5A) = 0.263V. The next
highest minimum available threshold is 0.265V of the
MAX590_ _BEUT, which is an ideal choice given these
3
4
V
IN
= -9V to -90V
8
_______________________________________________________________________________________
-100V SOT23 Simple Swapper Hot-Swap
Controllers
Layout Guidelines
Good thermal contact between the MAX5900/
MAX5901 and the external MOSFET is essential for the
GROUND
thermal shutdown feature to operate effectively. Place
U1
the MAX5900/MAX5901 as close as possible to the
SOT23-6
MAX5900/MAX5901
drain of the external MOSFET, and use wide circuit
board traces for good heat transfer. See Figure 5 for an
example of a PC board layout.
POWER IN
S
D G
M1
SOT-223
POWER
OUT
Chip Information
TRANSISTOR COUNT: 678
Figure 5. Circuit Board Layout Example.
PROCESS TECHNOLOGY: BiCMOS
GND
GND
100kΩ
100µF
+
V
MAX5900
MAX5901
50kΩ
+
-
V
IN
V
MAX5900
MAX5901
PGOOD
ON/OFF
V
IN
V
-
PGOOD
ON/OFF
(PGOOD)
(PGOOD)
V
EE
GATE DRAIN
V
EE
GATE DRAIN
(a) SUPPLY CURRENT
(b) V
UVLO
GND
GND
100kΩ
+
-
MAX5900A
MAX5901A
48V
+
PGOOD
ON/OFF
MAX5900
MAX5901
V
IN
V
PGOOD
(PGOOD)
ON/OFF
V
-
(PGOOD)
V
GATE DRAIN
SCOPE
EE
GATE DRAIN
EE
V
SCOPE
50kΩ
(c) GATE DRIVE VOLTAGE
(d) RETRY TIMEOUT
GND
GND
50kΩ
50kΩ
R
L
+
C
L
MAX5900
MAX5901
+
-
48V
-
PGOOD
MAX5900
MAX5901
ON/OFF
48V
PGOOD
(PGOOD)
ON/OFF
V
SCOPE
(PGOOD)
V
EE
GATE DRAIN
SCOPE
GATE DRAIN
SCOPE
EE
SCOPE
SCOPE
SCOPE
SCOPE
SCOPE
50kΩ
(e) TURN-ON WAVEFORMS
(f) CIRCUIT BREAKER EVENT
Figure 6. Test Circuits
_______________________________________________________________________________________
9
-100V SOT23 Simple Swapper Hot-Swap
Controllers
Selector Guide
CIRCUIT BREAKER
FUNCTION
CIRCUIT BREAKER
THRESHOLD
POWER-GOOD
OUTPUT LOGIC
PART
TOP MARK
AAQV
AAQJ
AAQK
AAQL
AAQM
AAQN
AAQO
AAQW
AAQP
AAQQ
AAQR
AAQS
AAQT
AAQU
MAX5900NNEUT*
MAX5900AAEUT*†
MAX5900ABEUT*
MAX5900ACEUT*†
MAX5900LAEUT*†
MAX5900LBEUT*
MAX5900LCEUT*
MAX5901NNEUT*
MAX5901AAEUT*
MAX5901ABEUT*†
MAX5901ACEUT*†
MAX5901LAEUT*†
MAX5901LBEUT*
MAX5901LCEUT*†
None
None
200mV
300mV
400mV
200mV
300mV
400mV
None
Active-Low
Active-Low
Active-Low
Active-Low
Active-Low
Active-Low
Active-Low
Active-High
Active-High
Active-High
Active-High
Active-High
Active-High
Active-High
Auto Retry
Auto Retry
Auto Retry
Latched
Latched
Latched
None
Auto Retry
Auto Retry
Auto Retry
Latched
Latched
Latched
200mV
300mV
400mV
200mV
300mV
400mV
*Requires special solder temperature profile described in the Absolute Maximum Ratings section.
†Future product—contact factory for availability.
Typical Operating Circuits (Continued)
50W ISOLATED
POWER SUPPLY
BACKPLANE CIRCUIT CARD
GND
HOT-SWAP CONTROLLER
V+
MAX5901
1MΩ
39kΩ
MAX5003*
INDIV
GND
ON/OFF
PGOOD
DRAIN
GATE
V
EE
GND
-48V
IRF540NS
FUSE
* MAX5003 IS A 110V PWM CONTROLLER
10 ______________________________________________________________________________________
-100V SOT23 Simple Swapper Hot-Swap
Controllers
Package Information
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 11
© 2001 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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