19-1694; Rev 1a; 4/01
KIT
ATION
EVALU
BLE
AVAILA
3V to 12V Current-Limiting Hot Swap Controllers
with Autoretry, DualSpeed/BiLevel Fault Protection
General Description
The MAX4271/MAX4272/MAX4273 comprise a com-
plete family of integrated 3V to 12V hot-swap con-
trollers. They allow the safe insertion and removal of
circuit cards into live backplanes.
The discharged filter capacitors of the circuit card pro-
vide a low impedance to the live backplane. High in-
rush currents from the backplane to the circuit card can
burn up connectors and components, or momentarily
collapse the backplane power supply leading to a sys-
tem reset. This family of hot-swap controllers prevents
such problems by regulating the current to a preset
limit when the board is plugged in, allowing the system
to stabilize safely. After the startup cycle is completed,
two on-chip comparators provide DualSpeed/BiLevel™
protection against short circuits, load glitches, and
overcurrent conditions. In the event of a fault condition,
the load is disconnected. Fault recovery is handled by
unlatching (MAX4271), autoretry (MAX4272), or pro-
grammed (MAX4273) methods.
The MAX4271 family includes many integrated features
that reduce component count and design time. An on-
board charge pump provides the gate drive for a low-
cost, external N-FET. Integrated features like startup
current regulation and current glitch protection eliminate
external timing resistors and capacitors. Also featured
are an open-drain status output to indicate a fault condi-
tion, and an adjustable overcurrent response time.
The MAX4271 (latched fault protection) and MAX4272
(autoretry fault protection) come in 8-pin SO packages.
The MAX4273 (full function) comes in the space-saving
16-pin QSOP package and 16-pin SO package. All
parts are specified across the extended temperature
range, and have an absolute maximum rating of 15V to
provide extra protection against inductive kickback dur-
ing board removal.
DualSpeed/BiLevel is a trademark of Maxim Integrated
Products.
Features
o
Provide Safe Hot Swap for +3V to +12V Power
Supplies with Few External Components
o
Unique Current Regulation Architecture
Minimizes N-FET Linear Mode Duration
o
Autoretry Feature (MAX4272/MAX4273)
o
DualSpeed/BiLevel Current Limit Protects Against
Current Glitches and Short Circuits
o
Power-On RESET (MAX4273)
o
15V Absolute Maximum Rating Protects Against
Inductive Kickbacks During Board Removal
o
Internal Charge Pump Generates Gate Drive for
External N-MOSFET
o
Status Output Pin Indicates Fault/Safe Condition
o
Space-Saving 8-Pin SO, 16-Pin QSOP Packages
MAX4271/MAX4272/MAX4273
________________________Applications
Base Stations
RAID
Remote-Access Servers
Network Routers and
Switches
ISDN
Ordering Information
PART
MAX4271ESA
MAX4272ESA
MAX4273EEE
MAX4273ESE
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 SO
8 SO
16 QSOP
16 SO
Pin Configurations appear at end of data sheet.
Typical Operating Circuit
BACKPLANE
V
CC
REMOVABLE CARD
2.7V TO 13.2V
R
SENSE
M1
N
V
OUT
C
BOARD
IN
STAT
GND
ON
STAT
CSPD
ON
SENSE
GATE
MAX4271
MAX4272
CTIM
GND
C
TIM
________________________________________________________________
Maxim Integrated Products
1
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
3V to 12V Current-Limiting Hot Swap Controllers
with Autoretry, DualSpeed/BiLevel Fault Protection
MAX4271/MAX4272/MAX4273
ABSOLUTE MAXIMUM RATINGS
IN to GND ............................................................................+15V
STAT, OUTC, LLMON, AUXVCC to GND ...............-0.3V to +14V
GATE to GND ..............................................-0.3V to (V
IN
+ 8.5V)
GATE to LLMON (Note 1).........................................-1V to +8.5V
INC, ON to GND (Note 2) .........................................-1V to +14V
CEXT to GND ...............................................-8.5V to (V
IN
+ 0.3V)
CSPD, CTON,
REF to GND ...........-0.3V to the lower of (V
IN
+ 0.3V) or +12V
VSENSE, RTH, CTIM to GND.......................-0.3V to (V
IN
+ 0.3V)
Current into INC, ON (Note 2) ............................................±2mA
Current into Any Other Pin ...............................................±50mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SO (derate 5.9mW/°C above +70°C)..................471mW
16-Pin QSOP (derate 8.3mW/°C above +70°C)...........667mW
16-Pin SO (derate 8.7mW/°C above +70°C)................696mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1:
GATE can be pulled below LLMON, but current must be limited to 2mA.
Note 2:
INC and ON can be pulled below ground. Limiting the current to 2mA ensures that these pins are never lower than about -0.8V.
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
IN
= +2.7V to +13.2V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
IN
= +5V and T
A
= +25°C.) (Note 3)
PARAMETER
POWER SUPPLIES
Input Voltage Range
Supply Current
CURRENT CONTROL
Slow Comparator Threshold
Slow Comparator Response
Time
V
SC,TH
t
CSPD
V
IN
- V
SENSE
C
SPD
= floating
C
SPD
= 100nF to GND
5kΩ on
RTH to
V
IN
Fast Comparator Threshold
V
FC,TH
MAX4273
only
75kΩ
on RTH
to V
IN
RTH = GND
MAX4271/MAX4272
Fast Comparator Response
Time
SENSE Input Bias Current
MOSFET DRIVER
Startup Period
(Notes 4, 5)
Gate Charge Current
MAX4271/MAX4272 C
TIM
= 100nF
t
START
I
GATE
MAX4273 C
TON
= 100nF
No capacitor
GATE = IN (Note 6)
21
21
31
31
5.5
100
41
41
ms
µs
µA
t
FCD
I
B,SENSE
10mV overdrive, from overload condition to
gate discharging
V
SENSE
= V
IN
T
A
= +25°C
T
A
= T
MIN
to T
MAX
T
A
= +25°C
T
A
= T
MIN
to T
MAX
T
A
= +25°C
T
A
= T
MIN
to T
MAX
45
43.5
10
10
45
43.5
675
650
180
200
350
0.2
10
750
20
20
50
50
55
56
40
40
55
56
825
840
220
ns
µA
mV
mV
µs
ms
V
IN
I
Q
V
ON
= V
IN
2.7
0.6
13.2
1
V
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
3V to 12V Current-Limiting Hot Swap Controllers
with Autoretry, DualSpeed/BiLevel Fault Protection
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= +2.7V to +13.2V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
IN
= +5V and T
A
= +25°C.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
Time from trigger to V
GATE
< 0.1V
(triggered by either the ON input or the
slow comparator), C
GATE
= 1000pF to
GND
Time from current overload to V
GATE
< 0.1V
(triggered by the fast comparator, during
normal operation), C
GATE
= 1000pF to GND
Voltage at which internal zener clamp
circuitry is triggered, measured with
respect to V
IN
(MAX4271/MAX4272),
measured with respect to V
LLMON
(MAX4273)
Measured with
respect to V
IN,
I
GATE
= 8.5µA
V
IN
≥
5V
V
IN
≥
2.7V
5
V
2.7
0.4
25
1
70
2.75
195
µA
75
200
550
mA
MIN
TYP
MAX
UNITS
MAX4271/MAX4272/MAX4273
Slow Turn-Off Time
t
SLOW,OFF
60
µs
Fast Turn-Off Time
t
FAST,OFF
15
µs
Maximum Gate Protection
Voltage
6.7
7.5
V
Minimum Gate Drive Voltage
During fast discharge, due to a fast
comparator fault in normal operation
Gate Discharge Current
I
GATE,DIS
During startup (current regulation provided
by fast comparator)
During normal discharge, due to a slow
comparator fault in normal mode, or by ON
going low
LLMON Overvoltage Threshold
GATE Overvoltage Threshold
LLMON Impedance
REFERENCE
(MAX4273)
Output Voltage
Line Regulation
Load Regulation
ON AND RESET COMPARATORS
Threshold Voltage
Hysteresis
Power-Supply Rejection Ratio
Propagation Delay
V
HYST
PSRR
t
D,COMP
2.7V
≤
V
IN
≤
13.2V
10mV overdrive, ON going positive or
negative, INC going negative
INC going positive
V
REF
∆
V
REF, LINE
Startup is initiated only after V
LLMON
is less
than this voltage (MAX4273)
Startup is initiated only after V
GATE
is less
than this voltage
Impedance to GND, after a fault (MAX4273)
No load, V
IN
= 5V
2.7V
≤
V
IN
≤
13.2V, no load
I
REF
= 0 to 100µA, V
IN
= 5V
0.1
0.1
1
1.164
1.2
1
0.6
1.236
8
3
0.6
V
V
kΩ
V
mV
mV
∆V
REF,
LOAD
V
IN
= 5V, rising threshold at ON or INC
0.575
0.6
3
0.625
±1
V
mV
mV/V
µs
10
100
150
200
ms
_______________________________________________________________________________________
3
3V to 12V Current-Limiting Hot Swap Controllers
with Autoretry, DualSpeed/BiLevel Fault Protection
MAX4271/MAX4272/MAX4273
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= +2.7V to +13.2V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
IN
= +5V and T
A
= +25°C.) (Note 3)
PARAMETER
Input Voltage Range
Input Bias Current
ON Pulse Width Low (Note 7)
DIGITAL OUTPUTS
(STAT, OUTC)
Output Leakage Current
Output Voltage Low
Retry Timeout Period
Default Retry
Timeout Period
V
OL
t
RETRY
t
RETRY
(default)
RETRY TIMING
(MAX4272, MAX4273)
100nF capacitor on C
TIM
(Note 5)
C
TIM
= no connection
0.5
1
176
2
s
µs
V
STAT
≤
13.2, V
OUTC
≤
13.2
I
SINK
= 1mA
1
0.4
µA
V
I
B,COMP
t
RESTART
To unlatch a fault MAX4271, MAX4273 with
C
TIM
= IN
20
SYMBOL
CONDITIONS
Input can be driven to the absolute
maximum limit without false output
inversion
MIN
-0.1
0.001
TYP
MAX
13.2
1
UNITS
V
µA
µs
UNDERVOLTAGE LOCKOUT
(UVLO)
Threshold
Hysteresis
Delay
V
UVLO
V
UVLO,HYST
t
D,UVLO
Time the input voltage must exceed
undervoltage lockout before startup is
initiated
100
Startup is initiated when this threshold is
exceeded at IN
2.25
100
150
200
2.67
V
mV
ms
Note 3:
All devices are 100% tested at T
A
= +25°C. All temperature limits are guaranteed by design.
Note 4:
Startup period is the time during which the slow comparator is ignored and the fast comparator regulates the sense current.
It is measured from the time ON is brought high.
Note 5:
Inferred from test with C
TIM
= 1nF.
Note 6:
The current available at GATE is a function of V
GATE
(see
Typical Operating Characteristics).
Note 7:
Guaranteed by design.
4
_______________________________________________________________________________________
3V to 12V Current-Limiting Hot Swap Controllers
with Autoretry, DualSpeed/BiLevel Fault Protection
Typical Operating Characteristics
(V
IN
= 5V, R
SENSE
= 100mΩ, C
BOARD
= 47µF, T
A
= +25°C, unless otherwise noted.)
MAX4271/MAX4272/MAX4273
SUPPLY CURRENT vs. INPUT VOLTAGE
MAX4271/3-01
SUPPLY CURRENT vs. TEMPERATURE
0.9
0.8
SUPPLY CURRENT (mA)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
V
IN
= 3V
V
IN
= 12V
V
IN
= 5V
ON = V
IN
MAX4271/3-02
SLOW COMPARATOR
RESPONSE TIME vs. INPUT VOLTAGE
240
230
220
t
CSPD
(µs)
210
200
190
180
MAX4271/3-03
1.0
0.9
0.8
SUPPLY CURRENT (mA)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
2
4
6
8
10
12
ON = GND
ON = V
IN
I
GATE
= 10µA
1.0
24
23
22
21
20
19
18
t
CSPD
(ms)
CSPD = 110nF
TIME IN ms
CSPD = 0
TIME IN
µs
14
0
-40
-15
10
35
60
85
0
2
4
6
8
10
12
14
V
IN
(V)
TEMPERATURE (°C)
V
IN
(V)
SLOW COMPARATOR THRESHOLD
vs. INPUT VOLTAGE
MAX4271/3-04
FAST COMPARATOR RESPONSE TIME
vs. OVERDRIVE VOLTAGE
MAX4271/3-05
FAST COMPARATOR RESPONSE TIME
vs. TEMPERATURE
MAX4271/3-06
51.0
50.8
50.6
50.4
V
SC,TH
(mV)
50.2
50.0
49.8
49.6
49.4
49.2
49.0
0
2
4
6
8
10
12
T
A
= +85°C
T
A
= -40°C
T
A
= +25°C
450
500
450
RESPONSE TIME (ns)
400
350
300
250
200
V
IN
= 3V
V
IN
= 5V
V
IN
= 12V
400
RESPONSE TIME (ns)
V
IN
= 12V
350
V
IN
= 5V
300
V
IN
= 3V
250
14
200
1
10
100
1000
OVERDRIVE VOLTAGE (mV)
-40
-15
10
35
60
85
V
IN
(V)
TEMPERATURE (°C)
FAST COMPARATOR THRESHOLD
vs. INPUT VOLTAGE
MAX4271/3-07
TIME TO FAST DISCHARGE GATE
vs. C
GATE
NO EXTERNAL MOSFET
DISCHARGE TO V
GATE
= 0.1V
MAX4271/3-08
STARTUP PERIOD
vs. INPUT VOLTAGE
350
C
TIM
= 100nF
TIME IN ms
MAX4271/3-09
210
208
206
204
V
FC,TH
(mV)
202
200
198
196
194
192
190
0
2
4
6
8
V
IN
(V)
10
12
T
A
= +85°C
T
A
= -40°C
T
A
= +25°C
100k
TIME TO DISCHARGE GATE (µs)
10k
1k
100
10
1
0.1
0.01
V
IN
= 3V
35
330
33
t
START
(ms)
t
START
(µs)
V
IN
= 12V
V
IN
= 5V
310
C
TIM
= 1nF
TIME IN
µs
31
290
29
270
27
14
0.1
1
10
100
1000
250
0
2
4
6
8
10
12
14
V
IN
(V)
25
C
GATE
(nF)
_______________________________________________________________________________________
5
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