19-3914; Rev 1; 1/06
IT
TION K
VALUA
E
BLE
AVAILA
Single PCI Express, Hot-Plug
Controller
General Description
Features
♦
PCI Express Compliant
♦
Hot Swaps 12V, 3.3V, and 3.3V Auxiliary for a
Single PCI-E Slot
♦
Integrated Power MOSFET for Auxiliary Supply
Rail
♦
Controls dI/dt and dV/dt
♦
Active Current Limiting Protects Against
Overcurrent/Short-Circuit Conditions
♦
Programmable Current-Limit Timeout
♦
PWRGD
Signal Output with Programmable
Power-On Reset (POR) (160ms Default)
♦
Latched
FAULT
Signal Output after Overcurrent
or Overtemperature Fault
♦
Attention Switch Input/Output with 4.4ms
Debounce
♦
Present-Detect Input
♦
Forced-On Input Facilitates Testing
♦
Thermal Shutdown
♦
Allows Control through SMBus with an I/O
Expander
MAX5954
The MAX5954 hot-plug controller is designed for PCI
Express™ applications. The device provides hot-plug
control for 12V, 3.3V, and 3.3V auxiliary supplies of a sin-
gle PCI Express (PCI-E) slot. The MAX5954’s logic
inputs/outputs allow interfacing directly with the system
hot-plug management controller or through an SMBus™
with an external I/O expander. Integrated debounced
attention switch and present-detect signals are included
to simplify system design.
The MAX5954 drives two external n-channel MOSFETs
to control the 12V and 3.3V main outputs. The 3.3V aux-
iliary output is controlled through an internal 0.3Ω
n-channel MOSFET. An internal charge pump provides
gate drive for the 12V output while the gate drive of the
3.3V output is driven by the 12V input supply. The 3.3V
auxiliary output is completely independent from the
main outputs with its own charge pump.
At power-up, the MAX5954 keeps all of the external
MOSFETs off until the supplies rise above their respec-
tive undervoltage-lockout (UVLO) thresholds. The
device keeps the internal MOSFET off only until the aux-
iliary input supply rises above its UVLO threshold. Upon
a turn-on command, the MAX5954 enhances the exter-
nal and internal MOSFETs slowly with a constant gate
current to limit the power-supply inrush current. The
MAX5954 actively limits the current of all outputs at all
times and shuts down if an overcurrent condition per-
sists for longer than a programmable overcurrent time-
out. Thermal-protection circuitry also shuts down all
outputs if the die temperature exceeds +150°C. After an
overcurrent or overtemperature fault condition, the
MAX5954L latches off while the MAX5954A automatical-
ly restarts after a restart time delay. The device is avail-
able in a 36-pin (6mm
×
6mm) thin QFN package and
operates over the -40°C to +85°C temperature range.
Ordering Information
PART
TEMP RANGE
PIN-
PACKAGE
36 Thin QFN
36 Thin QFN
PKG
CODE
T3666-3
T3666-3
MAX5954AETX+ -40°C to +85°C
MAX5954LETX+ -40°C to +85°C
+Denotes
lead free package.
Pin Configuration
N.C.
N.C.
T2
T1
N.C.
N.C.
N.C.
N.C.
N.C.
TOP VIEW
27 26 25 24 23 22 21 20 19
Applications
Servers
Desktop Mobile Server Platforms
Workstations
Embedded Devices
TIM
28
N.C.
29
N.C.
OUTPUT
INPUT
12VIN
GND
PGND
PORADJ
30
31
32
33
34
35
36
18
17
16
15
N.C.
N.C.
N.C.
N.C.
3.3VAUXIN
3.3VAUXO
PWRGD
FAULT
3.3G
MAX5954
14
13
12
11
10
+
Typical Application Circuit appears at end of data sheet.
SMBus is a trademark of Intel Corp.
PCI Express is a trademark of PCI-SIG Corp.
1
2
3
4
5
6
7
8
9
PRES-DET
FON
ON
AUXON
12S+
12S-
12G
THIN QFN
________________________________________________________________
Maxim Integrated Products
3.3S+
3.3S-
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.
Single PCI Express, Hot-Plug
Controller
MAX5954
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND, unless otherwise noted.)
12VIN......................................................................-0.3V to +14V
12G............................................................-0.3V to (V
12VIN
+ 6V)
12S, 12S-, 3.3G ......................................-0.3V to (V
12VIN
+ 0.3V)
3.3VAUXIN, ON,
FAULT
..........................................-0.3V to +6V
PWRGD
....................................................................-0.3V to +6V
PGND ....................................................................-0.3V to +0.3V
All Other Pins to GND......................-0.3V to (V
3.3VAUXIN
+ 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
36-Pin Thin QFN (derate 26.3mW/°C above +70°C).....2.105W
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
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
12VIN
= V
12S-
= V
12S+
= 12V, V
3.3S+
= V
3.3S-
= V
3.3VAUXIN
= V
ON
= V
AUXON
= V
FON
= 3.3V,
PWRGD
=
FAULT
= PORADJ = TIM =
OUTPUT = 12G = 3.3G = OPEN, INPUT =
PRES-DET
= PGND = GND, T
A
= -40°C to +85°C, unless otherwise noted. Typical values
are at T
A
= +25°C.) (Note 1)
PARAMETER
12V SUPPLY
12V Supply Voltage Range
12VIN Undervoltage Lockout
12VIN Supply Current
12VIN CONTROL
12VIN Current-Limit
Threshold (V
12S+
- V
12S-
)
12G Gate Charge Current
12G Gate Discharge Current
12G Gate High Voltage
(V
12G
- V
12VIN
)
12G Threshold Voltage For
PWRGD
Assertion
12S- Input Bias Current
12S+ Input Bias Current
3.3V SUPPLY
3.3V Supply Voltage Range
Undervoltage Lockout
(Note 3)
V
3.3S+
3.3S+ rising
Hysteresis
3.0
2.52
3.3
2.65
30
3.6
2.78
V
V
mV
20
V
12ILIM
I
12G_CHG
I
12G_DIS
V
12G
= GND
Normal turn-off, ON = GND, V
12G
= 2V
Output short-circuit condition, strong gate pulldown
to regulation, V
12VIN
- V
12S_
≥
1V, V
12G_
= 5V
I
12G
= 1µA
Referred to V
12VIN
, I
12G_
= 1µA (Note 2)
49
4
50
50
4.8
3.0
54
5
150
120
5.3
4
59
6
250
180
5.8
4.8
1
60
mV
µA
µA
mA
V
V
µA
µA
V
12VIN
V
12UVLO
I
12VIN
10.8
12
10
0.1
0.5
1
13.2
10.5
V
V
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
12VIN
rising
Hysteresis
V
12VIN
= 13.2V
9.5
V
12GH
V
PGTH12
2
_______________________________________________________________________________________
Single PCI Express, Hot-Plug
Controller
ELECTRICAL CHARACTERISTICS (continued)
(V
12VIN
= V
12S-
= V
12S+
= 12V, V
3.3S+
= V
3.3S-
= V
3.3VAUXIN
= V
ON
= V
AUXON
= V
FON
= 3.3V,
PWRGD
=
FAULT
= PORADJ = TIM =
OUTPUT = 12G = 3.3G = OPEN, INPUT =
PRES-DET
= PGND = GND, T
A
= -40°C to +85°C, unless otherwise noted. Typical values
are at T
A
= +25°C.) (Note 1)
PARAMETER
3.3V CONTROL
3.3V Current-Limit Threshold
(V
3.3S+
- V
3.3S-
)
3.3G Gate Charge Current
3.3G Gate Discharge Current
3.3G Gate High Voltage
(V
3.3G
- V
3.3S+
)
3.3G Threshold Voltage For
PWRGD
Assertion
3.3S- Input Bias Current
3.3S+ Input Bias Current
3.3V AUXILIARY SUPPLY
3.3VAUXIN Supply Voltage
Range
3.3VAUXIN Undervoltage
Lockout
3.3VAUXIN Supply Current
3.3VAUXIN to 3.3VAUXO
Maximum Dropout
3.3VAUXO Current-Limit
Threshold
3.3VAUXO Threshold For
PWRGD
Assertion
(V
3.3VAUXIN
- V
3.3VAUXO
)
LOGIC SIGNALS
Input-Logic Threshold
(ON,
FON,
AUXON,
PRES-DET,
INPUT)
Input Bias Current
(ON, AUXON, INPUT)
FON, PRES-DET
Internal
Pullup
ON, AUXON High-to-Low
Deglitch Time
25
50
4
Rising edge
Hysteresis
1.0
25
1
75
2.0
V
mV
µA
kΩ
µs
V
3.3VAUXIN
V
3.3VAUXUVLO
3.3VAUXIN rising
Hysteresis
V
3.3VAUXIN
= 3.6V
I
3.3VAUXO
= 375mA
3.3VAUXO shorted to GND
376
470
3.0
2.52
3.3
2.65
30
1.5
3
225
564
3.6
2.78
V
V
mV
mA
mV
mA
20
V
3.3ILIM
I
3.3G CHG
I
3.3G_DIS
V
3.3G
= GND
ON = GND, V
3.3G
= 2V
Output short-circuit condition, strong gate pulldown
to regulation, V
3.3S+
- V
3.3S
≥
1V, V
3.3G
= 5V
Sourcing 1µA
Referred to V
3.3VAUXIN
, I
3.3G
= 1µA (Note 2)
17
4
50
100
4.5
-3.0
20
5
150
150
5.5
+4
23
6
250
220
6.8
+4.5
1
60
mV
µA
µA
mA
V
V
µA
µA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX5954
V
3.3G_H
V
PGTH3.3
V
PGTH3.3AUX
(Note 3)
400
mV
_______________________________________________________________________________________
3
Single PCI Express, Hot-Plug
Controller
MAX5954
ELECTRICAL CHARACTERISTICS (continued)
(V
12VIN
= V
12S-
= V
12S+
= 12V, V
3.3S+
= V
3.3S-
= V
3.3VAUXIN
= V
ON
= V
AUXON
= V
FON
= 3.3V,
PWRGD
=
FAULT
= PORADJ = TIM =
OUTPUT = 12G = 3.3G = OPEN, INPUT =
PRES-DET
= PGND = GND, T
A
= -40°C to +85°C, unless otherwise noted. Typical values
are at T
A
= +25°C.) (Note 1)
PARAMETER
PRES-DET
High-to-Low
Deglitch Time
PWRGD
Power-On Reset
Time (Note 2)
PWRGD
Low-to-High Deglitch
Time
PWRGD, FAULT
Output Low
Voltage
PWRGD, FAULT
Output-High
Leakage Current
SYMBOL
t
DEG
PORADJ = open
t
POR_HL
R
PORADJ
= 20kΩ
R
PORADJ
= 100kΩ
R
PORADJ
= 200kΩ
t
POR_LH
Sinking 2mA
Sinking 30mA
V
PWRGD
= V
FAULT
= 5.5V
TIM = open
FAULT
Timeout
t
FAULT
R
TIM
= 15kΩ
R
TIM
= 120kΩ
R
TIM
= 300kΩ
FAULT
Timeout During
Startup
Autorestart Delay Time
Fault Reset Minimum Pulse
Width
Thermal-Shutdown Threshold
Thermal-Shutdown Threshold
Hysteresis
OUTPUT Debounce Time
OUTPUT High Voltage
OUTPUT Low Voltage
t
DBC
Sourcing 2mA
Sinking 2mA
2.6
t
SU
t
RESTART
t
RESET
T
SD
(Note 4)
T
J
rising
5.5
1.4
12
11
2.6
22
59
2 x t
FAULT
64 x t
FAULT
100
+150
20
4.4
6.2
ms
ms
µs
°C
°C
ms
V
V
CONDITIONS
MIN
3
90
35
145
TYP
5
160
55
265
570
4
0.1
0.7
1
17.0
3.8
32
ms
µs
V
µA
MAX
7
250
75
380
ms
UNITS
ms
V
3.3VAUXIN
V
3.3VAUXIN
- 0.3
0.4
Note 1:
Note 2:
Note 3:
Note 4:
100% production tested at T
A
= +25°C. Parameters over temperature are guaranteed by design.
PWRGD
asserts a time t
POR_HL
after V
PGTH12
, V
PGTH3.3
, and V
PGTH3.3AUX
conditions are met.
The UVLO for the 3.3V supply is sensed at 3.3S+.
This is the time that ON or AUXON must stay low when resetting a fault condition.
4
_______________________________________________________________________________________
Single PCI Express, Hot-Plug
Controller
Typical Operating Characteristics
(V
12VIN
= V
12S+
= 12V, V
3.3VAUXIN
= V
3.3S+
= V
ON
= V
AUXON
= V
INPUT
= 3.3V,
PRES-DET
= GND, FON = PORADJ = TIM = float,
FAULT
= 10kΩ to 3.3VAUXIN,
PWRGD
= 10kΩ to 3.3VAUXO, T
A
= +25°C, unless otherwise noted, see the
Typical Application
Circuit.)
12VIN INPUT SUPPLY CURRENT
vs. TEMPERATURE
0.505
0.504
0.503
0.502
0.501
0.500
0.499
0.498
0.497
0.496
0.495
0.494
0.493
0.492
0.491
0.490
-40
-15
10
35
60
TEMPERATURE (°C)
MAX5954 toc01
MAX5954
3.3VAUXIN SUPPLY CURRENT
vs. TEMPERATURE
1.8
1.6
SUPPLY CURRENT (mA)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
MAX5954 toc02
ON AND AUXON LOW-TO-HIGH THRESHOLD
VOLTAGE vs. TEMPERATURE
1.9
THRESHOLD VOLTAGE (V)
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
-40
-15
10
35
60
85
TEMPERATURE (°C)
MAX5954 toc03
2.0
2.0
SUPPLY CURRENT (mA)
3.3VAUXO OUTPUT VOLTAGE vs. CURRENT
MAX5954 toc04
12G AND 3.3G GATE CHARGE
CURRENT vs. TEMPERATURE
MAX5954 toc05
12G AND 3.3G GATE DISCHARGE
CURRENT vs. TEMPERATURE
MAX5954 toc06
3.5
3.0
OUTPUT VOLTAGE (V)
2.5
2.0
1.5
1.0
0.5
0
0
0.1
0.2
0.3
0.4
0.5
5.35
5.30
GATE CHARGE CURRENT (µA)
5.25
5.20
5.15
5.10
5.05
5.00
4.95
4.90
4.85
3.3G
12G
170
GATE DISCHARGE CURRENT (µA)
165
3.3G
160
155
12G
150
145
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
0.6
OUTPUT CURRENT (A)
3.3VAUX INTERNAL SWITCH
MAXIMUM DROPOUT vs. TEMPERATURE
MAX5954 toc07
12V AND 3.3V CURRENT-LIMIT THRESHOLD
VOLTAGE vs. TEMPERATURE
MAX5954 toc08
AUXILIARY CURRENT LIMIT
vs. TEMPERATURE
0.495
AUXILIARY CURRENT LIMIT (A)
0.490
0.485
0.480
0.475
0.470
0.465
0.460
0.455
MAX5954 toc09
0.20
0.18
0.16
DROPOUT VOLTAGE (V)
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0
-40
-15
10
35
60
AUXILIARY OUTPUT CURRENT = 375mA
60
CURRENT-LIMIT THRESHOLD VOLTAGE (mV)
50
40
30
20
10
0
12V CURRENT-SENSE
THRESHOLD
0.500
3.3V CURRENT-SENSE
THRESHOLD
0.450
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
85
TEMPERATURE (°C)
_______________________________________________________________________________________
5
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