Maxim MAX5957LETN+ Triple pci express, hot-plug controller Datasheet

19-0884; Rev 0; 7/07
Triple PCI Express, Hot-Plug Controllers
The MAX5957/MAX5958 triple hot-plug controllers are
designed for PCI Express (PCIe)® applications. These
devices provide hot-plug control for 12V, 3.3V, and 3.3V
auxiliary supplies of three PCIe slots. The MAX5957/
MAX5958s’ logic inputs/outputs allow interfacing directly
with the system hot-plug management controller or
through an SMBus™ with an external I/O expander such
as the MAX7313. An integrated debounced attention
switch and present-detect signals simplify system design.
The MAX5957/MAX5958 drive six external n-channel
MOSFETs to control the 12V and 3.3V main outputs. The
3.3V auxiliary outputs are controlled through 0.2Ω n-channel MOSFETs. Internal charge pumps provide the gate
drive for the 12V outputs while the gate drive of the 3.3V
output is driven by the 12V input supply clamped to 5.5V
above the respective 3.3V main supply rail. The 3.3V auxiliary outputs are completely independent from the main
outputs with their own charge pumps.
At power-up, the MAX5957/MAX5958 keep all the
MOSFETs (internal and external) off until the supplies rise
above their respective undervoltage lockout (UVLO)
thresholds. Upon a turn-on command, the MAX5957/
MAX5958 enhance the external and internal MOSFETs
slowly with a constant gate current to limit the power-supply inrush current.
The MAX5957/MAX5958 actively limit the current to protect all outputs at all times and shut down if an overcurrent condition occurs. After an overcurrent fault condition,
the MAX5957L/MAX5958L latch off while the MAX5957A/
MAX5958A automatically restart after a restart time delay.
The MAX5957/MAX5958 are offered in latch-off or autorestart versions (see the Selector Guide).
The MAX5957/MAX5958 are available in a 56-pin TQFN
package and operate over the -40°C to +85°C temperature range.
Applications
Servers
Desktop Mobile Server Platforms
Workstations
Embedded Devices
Features
o PCIe Compliant
o Hot Swap 12V, 3.3V, and 3.3V Auxiliary for 3
PCIe Slots
o Integrated Power MOSFETs for Auxiliary Supply
Rails
o Controls di/dt and dV/dt
o Active Current Limiting Protects Against
Overcurrent/Short-Circuit Conditions
o Programmable Current-Limit Timeout
o PWRGD Signal Outputs with Programmable
Power-On Reset (POR) (160ms Default)
o Latched FAULT Signal Output After Overcurrent
or Overtemperature Fault
o Attention Switch Inputs/Outputs with 4ms
Debounce
o Present-Detect Inputs
o Force-On Inputs Facilitate Testing/Debug
o Thermal Shutdown
o Allow Control Through SMBus with an I/O
Expander
Ordering Information
PART
TEMP RANGE
PINPACKAGE
PKG
CODE
MAX5957AETN+
-40°C to +85°C
56 Thin QFN
T5677-1
T5677-1
MAX5957LETN+
-40°C to +85°C
56 Thin QFN
MAX5958AETN+
-40°C to +85°C
56 Thin QFN
T5677-1
MAX5958LETN+
-40°C to +85°C
56 Thin QFN
T5677-1
+Denotes a lead-free package.
Pin Configuration and Typical Application Circuit appear at
end of data sheet.
PCI Express is a registered trademark of PCI-SIG Corp.
SMBus is a trademark of Intel Corp.
Selector Guide
PART
LATCH OFF
MAX5957AETN+
MAX5957LETN+
GUARANTEED AUX CURRENT (mA)
√
375
√
375
√
MAX5958AETN+
MAX5958LETN+
AUTORESTART
√
550
550
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1
MAX5957/MAX5958
General Description
MAX5957/MAX5958
Triple PCI Express, Hot-Plug Controllers
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND, unless otherwise noted.)
12VIN......................................................................-0.3V to +14V
12G_ ..........................................................-0.3V to (V12VIN + 6V)
12S_+, 12S_-, 3.3G_ ..............................-0.3V to (V12VIN + 0.3V)
3.3VAUXIN, ON_, FAULT_, PWRGD_.......................-0.3V to +6V
PGND ....................................................................-0.3V to +0.3V
All Other Pins ..................................-0.3V to (V3.3VAUXIN + 0.3V)
Continuous Power Dissipation (TA = +70°C)
56-Pin Thin QFN (derate 40mW/°C above +70°C) .....3200mW
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
(V12VIN = V12S_+ = V12S_- = 12V, V3.3S_+ =V3.3S_- = V3.3AUXIN = VON_ = VAUXON_ = VFON_ = 3.3V, PWRGD_ = FAULT_ = PORADJ =
TIM = OUTPUT_ = 12G_ = 3.3G_ = OPEN, INPUT_ = PRES-DET_ = PGND = GND, TA = TJ = -40°C to +85°C, unless otherwise
noted. Typical values are at TA = TJ = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
12V SUPPLY (MAIN)
12V Supply Input-Voltage Range
V12VIN
12V Undervoltage Lockout
V12UVLO
12V Undervoltage Lockout
Deglitch Time
tDEG,UVLO
12V Supply Current
I12VIN
V12VIN rising
10.8
12
13.2
9.5
10
10.5
V
Hysteresis
0.1
V12IN falling below V12UVLO to UVLO
assertion
30
V12VIN = 13.2V
1
2.5
mA
49
54
59
mV
V12G_ = GND
4
5
6
µA
Normal turn-off, ON_ = GND,
V12G_ = 2V
50
150
250
µA
Output short-circuit condition, strong
gate pulldown to regulation,
(V12S+ - V12S-) ≥ 1V, V12G_ = 5V
60
120
200
mA
µs
12VIN CONTROL
12VIN Current-Limit Threshold
(V12S+ - V12S-)
12G_ Gate Charge Current
12G_ Gate Discharge Current
V12ILIM
I12G, CHG
I12G_, DIS
12G_ Gate High Voltage
(V12G_ - V12VIN)
V12G, H
I12G_ = 1µA
4.8
5.3
5.8
V
12G_ Threshold Voltage for
PWRGD_ Assertion
VPGTH12
Referred to V12VIN, I12G_ = 1µA
(Note 2)
3.0
4.0
4.8
V
1
µA
10
30
µA
3.0
3.3
3.6
V
2.50
2.65
2.78
12S_- Input Bias Current
12S_+ Input Bias Current
3.3V SUPPLY (MAIN)
3.3V Supply Voltage Range
Undervoltage Lockout (Note 3)
2
V3.3S_+
3.3SA+ rising
Hysteresis
30
_______________________________________________________________________________________
V
mV
Triple PCI Express, Hot-Plug Controllers
(V12VIN = V12S_+ = V12S_- = 12V, V3.3S_+ =V3.3S_- = V3.3AUXIN = VON_ = VAUXON_ = VFON_ = 3.3V, PWRGD_ = FAULT_ = PORADJ =
TIM = OUTPUT_ = 12G_ = 3.3G_ = OPEN, INPUT_ = PRES-DET_ = PGND = GND, TA = TJ = -40°C to +85°C, unless otherwise
noted. Typical values are at TA = TJ = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
17
20
23
mV
V3.3G_ = GND
4
5
6
µA
Normal turn-off, ON_ = GND,
V3.3G_ = 2V
50
150
250
µA
Output short-circuit condition, strong
gate pulldown to regulation,
V3.3S_+ - V3.3S_- ≥ 1V, V3.3G- = 5V
90
150
250
mA
ISOURCE = 1µA
4.5
5.5
6.8
V
Referred to V3.3AUXIN, I3.3G_ = 1µA
(Note 2)
3.0
4.0
4.5
V
1
µA
20
60
µA
3.0
3.3
3.6
V
2.50
2.65
2.78
3.3V CONTROL
3.3V Current-Limit Threshold
(V3.3S_+ - V3.3S_-)
V3.3ILIM
3.3G_ Gate Charge Current
I3.3G_,CHG
3.3G_ Gate Discharge Current
3.3G_ Gate High Voltage
(V3.3G_- V3.3S_+)
3.3G_ Threshold Voltage for
PWRGD_ Assertion
I3.3G_, DIS
V3.3G_H
VPGTH3.3
3.3S_- Input Bias Current
3.3S_+ Input Bias Current
3.3V AUXILIARY SUPPLY
3.3VAUXIN Supply Input Voltage
Range
3.3VAUXIN Undervoltage
Lockout
V3.3AUXIN
V3.3VAUXUVLO
V3.3VAUXIN rising
Hysteresis
30
3.3VAUXIN Supply Current
V3.3VAUXIN = 3.6V
2.5
3.3VAUXIN to 3.3VAUXO
Maximum Dropout
I3.3VAUXO = 375mA (MAX5957)
225
I3.3VAUXO = 550mA (MAX5958)
280
3.3VAUXO_ Current-Limit
Threshold
3.3VAUXO_ shorted
to GND
3.3VAUXO_ Threshold for
PWRGD_ Assertion (V3.3VAUXIN
- V3.3VAUXO)
VPGTH3.3AUX
5
MAX5957
376
450
564
MAX5958
560
700
850
(Note 2)
V
mV
mA
mV
mA
400
mV
2.0
V
LOGIC SIGNALS
Input-Logic Threshold (ON_,
FON_, AUXON_, PRES-DET_,
INPUT_)
Rising edge
1.0
Hysteresis
25
Input Bias Current (ON_,
AUXON_, INPUT_)
FON_, PRES-DET_ Internal Pullup
ON_, AUXON_ High-to-Low
Deglitch Time
25
50
4
mV
1
µA
75
kΩ
µs
_______________________________________________________________________________________
3
MAX5957/MAX5958
ELECTRICAL CHARACTERISTICS (continued)
MAX5957/MAX5958
Triple PCI Express, Hot-Plug Controllers
ELECTRICAL CHARACTERISTICS (continued)
(V12VIN = V12S_+ = V12S_- = 12V, V3.3S_+ =V3.3S_- = V3.3AUXIN = VON_ = VAUXON_ = VFON_ = 3.3V, PWRGD_ = FAULT_ = PORADJ =
TIM = OUTPUT_ = 12G_ = 3.3G_ = OPEN, INPUT_ = PRES-DET_ = PGND = GND, TA = TJ = -40°C to +85°C, unless otherwise
noted. Typical values are at TA = TJ = +25°C.) (Note 1)
PARAMETER
SYMBOL
PRES-DET_ High-to-Low Deglitch
Time
tDEG
CONDITIONS
MIN
TYP
MAX
UNITS
3
5
7
ms
1
µs
90
160
250
VPORADJ = GND
PWRGD_ Power-On Reset
Deglitch Time (Note 2)
PORADJ = unconnected
tPOR_HL
RPORADJ = 20kΩ
35
55
75
RPORADJ = 100kΩ
145
265
380
RPORADJ = 200kΩ
PWRGD_ Low-to-High Deglitch
Time
PWRGD_, FAULT_ Output High
Leakage Current
FAULT_ Timeout
530
4
tPOR_LH
PWRGD_, FAULT_ Output Low
Voltage
0.1
ISINK = 30mA
0.8
1
TIM = open
5.5
11
17
RTIM = 15kΩ
1.4
2.6
3.8
RTIM = 120kΩ
12
22
32
RTIM = 300kΩ
FAULT_ Timeout During Startup
Autorestart Delay Time
Fault Reset Minimum Pulse Width
Thermal Shutdown Threshold
ms
2x
tFAULT
ms
tRESTART
64 x
tFAULT
ms
µs
tRESET
(Note 4)
100
tSD
TJ rising
150
°C
20
tDBC
2.6
ISOURCE = 2mA
OUT_ Voltage Low
ISINK = 2mA
4
µA
tSU
OUT_ Voltage High
Note 1:
Note 2:
Note 3:
Note 4:
V
53
Thermal Shutdown Hysteresis
OUT_ Debounce Time
µs
ISINK = 2mA
PWRGD_, FAULT_ = 5.5V
tFAULT
ms
4.4
V3.3AUXIN
- 0.3
All devices are 100% production tested at TA = +25°C. Limits over temperature are guaranteed by design.
PWRGD_ asserts a time tPOR_HL after VPGTH12, VPGTH3.3, and VPGTH3.3AUX 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.
_______________________________________________________________________________________
6.2
ms
V3.3AUXIN
V
0.4
V
Triple PCI Express, Hot-Plug Controllers
(V12VIN = V12S_+ = 12V, V3.3S_+ = V3.3S_- = V3.3AUXIN = VON_ = VAUXON_ = VFON_ = 3.3V, PWRGD_ = FAULT_ = PORADJ = TIM =
OUTPUT_ = OPEN, INPUT_ = PRES-DET_ = PGND = GND. See the Typical Application Circuit.)
1.02
1.00
0.98
0.96
0.94
3.5
3.0
2.5
2.0
1.5
-15
10
35
60
1.0
1.50
ON_ THRESHOLD
1.45
1.40
AUXON_ THRESHOLD
1.35
1.30
1.25
1.20
-40
85
-15
10
35
60
-40
85
-15
10
35
60
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
3.3VAUXO_ OUTPUT VOLTAGE
vs. OUTPUT CURRENT
12G_ AND 3.3G_ GATE CHARGE
CURRENT vs. TEMPERATURE
12G_ AND 3.3G_ GATE DISCHARGE
CURRENT vs. TEMPERATURE
3.0
MAX5957
MAX5958
2.5
2.0
1.5
1.0
0.5
12G_
5.10
5.05
5.00
4.95
3.3G_
4.90
4.85
85
MAX5957 toc06
5.15
180
GATE DISCHARGE CURRENT (µA)
3.5
5.20
MAX5957 toc05
MAX5957 toc04
4.0
GATE CHARGE CURRENT (µA)
-40
MAX5957 toc03
1.55
0
0.90
175
170
3.3G_
165
160
12G_
155
4.80
0
150
4.75
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
-40
-15
10
35
60
-40
85
-15
10
35
60
TEMPERATURE (°C)
TEMPERATURE (°C)
3.3VAUX INTERNAL SWITCH
MAXIMUM DROPOUT vs. TEMPERATURE
12V AND 3.3V CURRENT-LIMIT THRESHOLD
VOLTAGE vs. TEMPERATURE
AUXILIARY CURRENT LIMIT
vs. TEMPERATURE
ILOAD = 550mA
MAX5958
0.16
0.14
0.12
0.10
0.08
ILOAD = 375mA
MAX5957
0.06
0.04
0.02
0
-40
-15
10
35
TEMPERATURE (°C)
60
85
60
50
12V CURRENT-LIMIT
THRESHOLD
40
3.3V CURRENT-LIMIT
THRESHOLD
30
1.00
20
85
MAX5957 toc09
0.18
MAX5957 toc07
0.20
12V AND 3.3V CURRENT-LIMIT THRESHOLD (mV)
OUTPUT CURRENT (A)
0.90
AUXILIARY CURRENT (mA)
OUTPUT VOLTAGE (V)
4.0
0.5
0.92
DROPOUT VOLTAGE (V)
1.60
THRESHOLD VOLTAGE (V)
1.04
4.5
MAX5957 toc08
SUPPLY CURRENT (mA)
1.06
5.0
MAX5957 toc02
1.08
3.3VAUXIN SUPPLY CURRENT (mA)
MAX5957 toc01
1.10
ON_ AND AUXON_ LOW-TO-HIGH THRESHOLD
VOLTAGE vs. TEMPERATURE
3.3VAUXIN SUPPLY CURRENT
vs. TEMPERATURE
12V INPUT SUPPLY CURRENT
vs. TEMPERATURE
0.80
0.70
MAX5958
0.60
0.50
MAX5957
0.40
0.30
0.20
10
0.10
0
0
-40
-15
10
35
TEMPERATURE (°C)
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
_______________________________________________________________________________________
5
MAX5957/MAX5958
Typical Operating Characteristics
Typical Operating Characteristics (continued)
(V12VIN = V12S_+ = 12V, V3.3S_+ = V3.3S_- = V3.3AUXIN = VON_ = VAUXON_ = VFON_ = 3.3V, PWRGD_ = FAULT_ = PORADJ = TIM =
OUTPUT_ = OPEN, INPUT_ = PRES-DET_ = PGND = GND. See the Typical Application Circuit.)
12V UNDERVOLTAGE LOCKOUT
THRESHOLD vs. TEMPERATURE
3.3VAUXON UNDERVOLTAGE LOCKOUT
THRESHOLD vs. TEMPERATURE
2.68
2.66
UVLO THRESHOLD (V)
10.10
10.05
10.00
9.95
9.90
MAX5957 toc11
10.15
12V TURN-ON/TURN-OFF TIME
MAX5957 toc12
2.70
MAX5957 toc10
10.20
UVLO THRESHOLD (V)
MAX5957/MAX5958
Triple PCI Express, Hot-Plug Controllers
10V/div
12V OUTPUT
VOLTAGE
20V/div
12G_
5V/div
ON_
5V/div
PWRGD_
2.64
2.62
2.60
2.58
2.56
2.54
9.85
2.52
9.80
2.50
-40
-15
10
35
60
85
-40
-15
TEMPERATURE (°C)
10
35
60
85
40ms/div
TEMPERATURE (°C)
3.3V TURN-ON/TURN-OFF TIME
3.3V AUXILIARY TURN-ON/TURN-OFF TIME
MAX5957 toc13
MAX5957 toc14
3.3AUXO_OUTPUT
VOLTAGE
2V/div
3.3V OUTPUT
5V/div
3.3G_
10V/div
PWRGD_
2V/div
ON_
5V/div
PWRGD_
5V/div
AUXON_
2V/div
40ms/div
40ms/div
TURN-ON DELAY 3.3V OUTPUT AND
3.3V AUXILIARY OUTPUT
FAULT CONDITION ON 12V MAIN OUTPUT
(AUTORESTART OPTION)
MAX5957 toc15
MAX5957 toc16
RLOAD STEP TO 1.5Ω
5V/div
3.3VAUXO_
OUTPUT VOLTAGE
5V/div
3.3 INPUT,
3.3VAUXIN
5V/div
3.3 OUTPUT VOLTAGE
5V/div
PWRGD
12V OUTPUT CURRENT
5A/div
0A
12G_
20V/div
0V
12V OUTPUT VOLTAGE
10V/div
0V
3.3G_
10V/div
tRESTART
0V
4ms/div
6
100ms/div
_______________________________________________________________________________________
FAULT_
5V/div
Triple PCI Express, Hot-Plug Controllers
FAULT CONDITION ON AUXILIARY OUTPUT
(AUTORESTART OPTION)
FAULT CONDITION ON 3.3V MAIN OUTPUT
(AUTORESTART OPTION)
MAX5957 toc18
MAX5957 toc17
RLOAD STEP TO 4Ω
RLOAD STEP TO 0.5Ω
3.3VAUXO_ OUTPUT CURRENT
500mA/div
3.3V MAIN OUTPUT CURRENT
2A/div
0A
0A
0V
3.3G_
10V/div
0V
3.3V OUTPUT VOLTAGE
5V/div
tRESTART
3.3VAUXO_ OUTPUT VOLTAGE
2V/div
0V
0V
100ms/div
100ms/div
FAULT CONDITION ON 12V OUTPUT
(LATCH OPTION MAX5958)
FAULT CONDITION ON 12V OUTPUT
MAX5957 toc20
MAX5957 toc19
RLOAD STEP TO 1.5Ω
12V OUTPUT CURRENT
5A/div
RLOAD STEP
TO 1.5Ω
12V OUTPUT CURRENT
5A/div
tFAULT
12G_
20V/div
12G_
20V/div
12V OUTPUT VOLTAGE
10V/div
12V OUTPUT VOLTAGE
10V/div
FAULT_
5V/div
FAULT_
5V/div
4ms/div
100ms/div
FAULT CONDITION ON 3.3V OUTPUT
(LATCHOFF OPTION)
FAULT CONDITION ON 3.3V MAIN OUTPUT
MAX5957 toc21
MAX5957 toc22
RLOAD STEP TO 0.5Ω
3.3V OUTPUT CURRENT
2A/div
40ms/div
FAULT_
2V/div
0V
tRESTART
FAULT_
5V/div
tFAULT
RLOAD
STEP TO 0.5Ω
3.3V OUTPUT CURRENT
2A/div
3.3G_
10V/div
3.3G_
10V/div
3.3V OUTPUT VOLTAGE
5V/div
3.3V OUTPUT VOLTAGE
5V/div
FAULT_
5V/div
FAULT_
5V/div
4ms/div
_______________________________________________________________________________________
7
MAX5957/MAX5958
Typical Operating Characteristics (continued)
(V12VIN = V12S_+ = 12V, V3.3S_+ = V3.3S_- = V3.3AUXIN = VON_ = VAUXON_ = VFON_ = 3.3V, PWRGD_ = FAULT_ = PORADJ = TIM =
OUTPUT_ = OPEN, INPUT_ = PRES-DET_ = PGND = GND. See the Typical Application Circuit.)
MAX5957/MAX5958
Triple PCI Express, Hot-Plug Controllers
Typical Operating Characteristics (continued)
(V12VIN = V12S_+ = 12V, V3.3S_+ = V3.3S_- = V3.3AUXIN = VON_ = VAUXON_ = VFON_ = 3.3V, PWRGD_ = FAULT_ = PORADJ = TIM =
OUTPUT_ = OPEN, INPUT_ = PRES-DET_ = PGND = GND. See the Typical Application Circuit.)
FAULT CONDITION ON AUXILIARY OUTPUT
(LATCHOFF OPTION)
FAULT CONDITION ON AUXILIARY OUTPUT
MAX5957 toc23
RLOAD STEP TO 3.5Ω
MAX5957 toc24
RLOAD
STEP TO 3Ω
tFAULT
3.3VAUXO_ OUTPUT CURRENT
500mA/div
3.3VAUXO_ OUTPUT CURRENT
500mA/div
3.3VAUXO_ OUTPUT VOLTAGE
2V/div
3.3VAUXO_ OUTPUT VOLTAGE
2V/div
MAX5958
MAX5958
FAULT_
2V/div
FAULT_
2V/div
100ms/div
10ms/div
SHORT CIRCUIT ON 12V MAIN OUTPUT
SHORT CIRCUIT ON 12V MAIN OUTPUT
MAX5957 toc25
MAX5957 toc26
12V OUTPUT CURRENT
5A/div
12V OUTPUT CURRENT
10A/div
12G_
20V/div
12V OUTPUT VOLTAGE
10V/div
FAULT_
5V/div
2ms/div
12G_
20V/div
0V
12V OUTPUT VOLTAGE
10V/div
0V
FAULT_
5V/div
4µs/div
SHORT CIRCUIT ON 3.3V MAIN OUTPUT
SHORT CIRCUIT ON 3.3V MAIN OUTPUT
MAX5957 toc27
MAX5957 toc28
2ms/div
8
0V
3.3V OUTPUT CURRENT
2A/div
3.3V OUTPUT CURRENT
10A/div
3.3G_
5V/div
3.3G_
5V/div
3.3V OUTPUT VOLTAGE
5V/div
3.3V OUTPUT VOLTAGE
5V/div
FAULT_
5V/div
FAULT_
5V/div
0V
2µs/div
_______________________________________________________________________________________
Triple PCI Express, Hot-Plug Controllers
SHORT CIRCUIT ON
3.3AUXO_ AUXILIARY OUTPUT
SHORT CIRCUIT ON 3.3VAUXO_
AUXILIARY OUTPUT
MAX5957 toc30
MAX5957 toc29
3.3VAUXO_ OUTPUT CURRENT
500mA/div
3.3VAUXO_ OUTPUT CURRENT
5A/div
0A
3.3VAUXO_ OUTPUT VOLTAGE
2V/div
3.3VAUXO_ OUTPUT VOLTAGE
2V/div
0A
FAULT_
5V/div
FAULT_
5V/div
MAX5958
MAX5958
4µs/div
2ms/div
POWER-UP INTO FAULT
(AUXILIARY SUPPLY)
POWER-UP INTO FAULT (3.3V MAIN)
MAX5957 toc31
MAX5957 toc32
RLOAD = 3Ω
3.3VAUXO_ OUTPUT CURRENT
500mA/div
tSU
3.3VAUXO_ OUTPUT VOLTAGE
2V/div
AUXON_
5V/div
FAULT_
5V/div
MAX5958
5A/div
3.3V OUTPUT
CURRENT
5V/div
3.3G_
2V/div
3.3V OUTPUT
VOLTAGE
5V/div
ON_, AUXON_
5V/div
FAULT_
4ms/div
4ms/div
POWER-UP INTO FAULT
(12V MAIN OUTPUT)
PRESENT-DETECT (ON/OFF) OPERATION
MAX5957 toc34
MAX5957 toc33
tSU
12V OUTPUT CURRENT
5A/div
10V/div
12V OUTPUT
VOLTAGE
12G_
10V/div
12V OUTPUT VOLTAGE
10V/div
ON_, AUXON_
5V/div
5V/div
3.3VAUXO_
OUTPUT VOLTAGE
5V/div
PWRGD_
5V/div
PRES-DET_
FAULT_
5V/div
4ms/div
40ms/div
_______________________________________________________________________________________
9
MAX5957/MAX5958
Typical Operating Characteristics (continued)
(V12VIN = V12S_+ = 12V, V3.3S_+ = V3.3S_- = V3.3AUXIN = VON_ = VAUXON_ = VFON_ = 3.3V, PWRGD_ = FAULT_ = PORADJ = TIM =
OUTPUT_ = OPEN, INPUT_ = PRES-DET_ = PGND = GND. See the Typical Application Circuit.)
Typical Operating Characteristics (continued)
(V12VIN = V12S_+ = 12V, V3.3S_+ = V3.3S_- = V3.3AUXIN = VON_ = VAUXON_ = VFON_ = 3.3V, PWRGD_ = FAULT_ = PORADJ = TIM =
OUTPUT_ = OPEN, INPUT_ = PRES-DET_ = PGND = GND. See the Typical Application Circuit.)
PRESENT-DETECT (ON/OFF) OPERATION
FORCED-ON (ON/OFF) OPERATION
MAX5957 toc35
MAX5957 toc36
10V/div
12V OUTPUT
VOLTAGE
10V/div
5V/div
3.3V OUTPUT
VOLTAGE
5V/div
3.3V AUXO_
OUTPUT VOLTAGE
5V/div
PWRGD_
5V/div
PWRGD_
5V/div
PRES-DET_
5V/div
FON_
12V OUTPUT
VOLTAGE
4ms/div
40ms/div
FORCED-ON (ON/OFF) OPERATION
DEBOUNCED INPUT/OUTPUT OPERATION
MAX5957 toc37
10V/div
MAX5957 toc38
12V OUTPUT
VOLTAGE
5V/div
3.3V OUTPUT
VOLTAGE
5V/div
PWRGD_
5V/div
FON_
INPUT_
2V/div
OUTPUT_
2V/div
10ms/div
4ms/div
POWER-ON-RESET TIME
vs. PORADJ RESISTOR
tFAULT TIME DELAY vs. TIM RESISTOR
MAX5957 toc40
MAX5957 toc39
2400
2200
2000
1800
1600
1400
1200
1000
800
600
400
200
0
180
160
140
120
100
80
60
40
20
0
0 100 200 300 400 500 600 700 800 900 1000
RPORADJ (kΩ)
10
200
tFAULT (ms)
tPOR_HL (ms)
MAX5957/MAX5958
Triple PCI Express, Hot-Plug Controllers
0
200
400
600
800
RTIM (kΩ)
______________________________________________________________________________________
1000
Triple PCI Express, Hot-Plug Controllers
PIN
NAME
FUNCTION
1
12SB-
Slot B 12V Negative Current-Sense Input. Connect 12SB- to the negative side of the current-sense
resistor using the Kelvin-sensing technique to ensure accurate current sensing.
2
12SB+
Slot B 12V Positive Current-Sense Input. Connect the positive terminal of the current-sense resistor
to 12SB+ using the Kelvin-sensing technique to ensure accurate current sensing.
3
AUXONB
Slot B 3.3V Auxiliary Output Enable. A logic-high at AUXONB turns on the slot B auxiliary output.
4
ONB
Slot B 12V and 3.3V Main Outputs Enable. A logic-high at ONB turns on the 12V and 3.3V main
outputs of slot B (see Table 2).
5
INPUT1
6
OUTPUT1
7
INPUT2
Digital Logic Gate Input 1
Digital Output One. 4ms debounced digital output of INPUT1.
Digital Logic Gate Input 2
8
OUTPUT2
9, 27
GND
Ground
Digital Output 2. 4ms debounced digital output of INPUT2.
10
FONC
Slot C Forced-On Input. FONC has a 50kΩ internal pullup to 3.3VAUXIN. A logic-low on FONC turns
on all slot C outputs as long as the power inputs are within their operating range, regardless of the
status of the other input signals. Leave FONC unconnected for normal operation.
11
PRES-DETC
Slot C Present-Detect Input. PRES-DETC accepts inputs from PRSNT-# on a PCIe connector. PRESDETC has an internal 50kΩ pullup to 3.3VAUXIN. When PRES-DETC is low, the outputs follow the
command from ONC and AUXONC after a 4ms debounced time. When PRES-DETC goes from low
to high, all outputs of the respective slot shut down with no delay.
12
ONC
Slot C 12V and 3.3V Main Outputs Enable. A logic-high at ONC turns on the 12V and 3.3V main
outputs of slot C (see Table 2).
13
AUXONC
Slot C 3.3V Auxiliary Output Enable. A logic-high at AUXONC turns on the slot C auxiliary output.
14
12SC+
Slot C 12V Positive Current-Sense Input. Connect the positive terminal of the current-sense resistor
to 12SC+ using the Kelvin-sensing technique to ensure accurate current sensing.
15
12SC-
Slot C 12V Negative Current-Sense Input. Connect 12SC- to the negative side of the current-sense
resistor using the Kelvin-sensing technique to ensure accurate current sensing.
16
12GC
Slot C 12V Gate-Drive Output. Connect 12GC to the gate of slot C’s 12V MOSFET. At power-up,
12GC is raised to the internal charge-pump voltage level by a constant current.
17
3.3SC+
Slot C 3.3V Positive Current-Sense Input. Connect the positive side of the current-sense resistor to
3.3SC+ using the Kelvin-sensing technique to ensure accurate current sensing.
18
3.3SC-
Slot C 3.3V Negative Current-Sense Input. Connect to the negative side of the sense resistor using
the Kelvin-sensing technique to ensure accurate current sensing.
19
3.3GC
Slot C 3.3V Gate-Drive Output. Connect 3.3GC to the gate of slot C’s 3.3V MOSFET. At power-up,
3.3GC is charged to 5.5V above the 3.3V supply by a constant current derived from V12VIN. V3.3GC‘s
rise time is determined by the external gate capacitance.
20
FAULTC
Open-Drain Fault Output Signal. FAULTC latches active low whenever slot C outputs are shut down
due to a fault. A fault is either of:
• An overcurrent condition lasting longer than the overcurrent timeout.
• A device over the temperature condition.
If the fault is detected in the main outputs, FAULTC must be reset by toggling the ONC input. If the
fault is in the auxiliary output, FAULTC must be reset by toggling both ONC and AUXONC. For the
autorestart version, FAULTC is reset when the part initiates the next power-on cycle.
21
PWRGDC
Open-Drain Power-Good Output. PWRGDC goes low 160ms after all outputs of slot C reach their
final value and the power MOSFETs are fully enhanced.
______________________________________________________________________________________
11
MAX5957/MAX5958
Pin Description
Triple PCI Express, Hot-Plug Controllers
MAX5957/MAX5958
Pin Description (continued)
12
PIN
NAME
22
3.3AUXOC
Slot C 3.3V Auxiliary Power-Supply Output
FUNCTION
23, 48, 49
3.3VAUXIN
3.3V Auxiliary Supply Input. 3.3VAUXIN is the input to a charge pump that drives the internal
MOSFETs connecting 3.3VAUXIN to 3.3AUXO_. V3.3AUXIN is also used to power the internal control
logic and analog references of the MAX5957/MAX5958 and must always be connected to a supply
between 3V and 3.6V. Bypass 3.3AUXIN with a 0.1µF capacitor to GND.
24, 46
PGND
25
TIM
Overcurrent Timeout Programming Input. Connect a resistor between 500Ω and 500kΩ from TIM to
GND to program tFAULT. Leave TIM unconnected for a default timeout of 11ms.
26
PORADJ
Power-On-Reset Programming Input. Connect a resistor between 500Ω and 500kΩ from PORADJ to
GND to program the POR timing. Leave unconnected for a default value of 160ms. Connect
PORADJ to GND to completely skip the POR time delay for PWGD_. Connect PORADJ to GND to
completely skip the POR time delay for PWRGD_ assertion.
27
GND
Ground
28
12VIN
12V Supply Input. V12VIN drives the gates of the MOSFETs connected to 3.3G_. 12VIN powers an
internal charge pump that drives the gates of the MOSFETs connected to 12G_. Bypass 12VIN with
a 1µF capacitor to GND.
29
N.C.
Power Ground. Connect externally to GND.
No Connection. Not internally connected.
30
PRES-DETB
Slot B Present-Detect Input. PRES-DETB accepts inputs from PRSNT#_# on a PCIe connector.
PRES-DETB has an internal 50kΩ pullup to 3.3VAUXIN. When PRES-DETB is low, the outputs follow
the command from ONB and AUXONB after a 4ms debounced time. When PRES-DETB goes from
low to high, all outputs of the respective slot shut down with no delay.
31
FONB
Slot B Forced-On Input. FONB has a 50kΩ internal pullup to 3.3VAUXIN. A logic-low on FONB turns
on all slot B outputs as long as the power inputs are within their operating range, regardless of the
status of the other input signals. Leave FONB unconnected for normal operation.
32
PRES-DETA
Slot A Present-Detect Input. PRES-DETA accepts inputs from PRSNT#_# on a PCIe connector.
PRES-DETA has an internal 50kΩ pullup to 3.3VAUXIN. When PRES-DETA is low, the outputs follow
the command from ONA and AUXONA after a 4ms debounced time. When PRES-DETA goes from
low to high, all outputs of the respective slot shut down with no delay.
33
FONA
Slot A Forced-On Input. FONA has a 50kΩ internal pullup to 3.3VAUXIN. A logic-low on FONA turns
on all slot A outputs as long as the power inputs are within their operating range, regardless of the
status of the other input signals. Leave FONA unconnected for normal operation.
34
OUTPUT3
35
INPUT3
36
ONA
37
AUXONA
38
12SA+
Slot A 12V Positive Current-Sense Input. Connect the positive terminal of the current-sense resistor
to 12SA+ using the Kelvin-sensing technique to ensure accurate current sensing.
39
12SA-
Slot A 12V Negative Current-Sense Input. Connect 12SA- to the negative side of the current-sense
resistor using the Kelvin-sensing technique to ensure accurate current sensing.
40
12GA
Slot A 12V Gate-Drive Output. Connect 12GA to the gate of slot A’s 12V MOSFET. At power-up,
V12GA is raised to the internal charge-pump voltage level by a constant current.
Digital Output 3. 4ms debounced digital output of INPUT3.
Digital Logic Gate Input 3
Slot A 12V and 3.3V Outputs Enable. A logic-high at ONA turns on the 12V and 3.3V outputs of slot
A (see Table 2).
Slot A 3.3V Auxiliary Output Enable. A logic-high at AUXONA turns on the slot A auxiliary output.
______________________________________________________________________________________
Triple PCI Express, Hot-Plug Controllers
PIN
NAME
FUNCTION
41
3.3SA+
Slot A 3.3V Positive Current-Sense Input. Connect the positive side of the current-sense resistor to
3.3SA+ using the Kelvin-sensing technique to ensure accurate current sensing.
42
3.3SA-
Slot A 3.3V Negative Current-Sense Input. Connect to the negative side of the sense resistor using
the Kelvin-sensing technique to ensure accurate current sensing.
43
3.3GA
Slot A 3.3V Gate-Drive Output. Connect 3.3GA to the gate of slot A’ s 3.3V MOSFET. At power-up,
V3.3GA is charged to 5.5V above the 3.3V supply by a constant current derived from V12VIN.
V3.3GA‘s rise time is determined by the external gate capacitance.
Open-Drain Fault Output Signal. FAULTA latches active low whenever slot A outputs are shut down
due to a fault. A fault is either of:
• An overcurrent condition lasting longer than the overcurrent timeout.
• A device overtemperature condition.
If the fault is detected in the main outputs, FAULTA must be reset by toggling the ONA input. If the
fault is in the auxiliary output, FAULTA must be reset by toggling both ONA and AUXONA. For the
autorestart version, FAULTA is reset when the part initiates the next power-on cycle.
Open-Drain Power-Good Output. PWRGDA goes low 160ms after all outputs of slot A reach their
final value and the power MOSFETs are fully enhanced.
Slot A 3.3V Auxiliary Power-Supply Output
Slot B 3.3V Auxiliary Power-Supply Output
Open-Drain Power-Good Output. PWRGDB goes low 160ms after all outputs of slot B reach their
final value and the power MOSFETs are fully enhanced.
Open-Drain Fault Output Signal. FAULTB latches active low whenever the slot B outputs are shut
down due to a fault. A fault is either of:
• An overcurrent condition lasting longer than the overcurrent timeout.
• A device over temperature condition.
If the fault is detected in the main outputs, FAULTB must be reset by toggling the ONB input. If the
fault is in the auxiliary output, FAULTB must be reset by toggling both ONB and AUXONB. For the
autorestart version, FAULTB is reset when the part initiates the next power-on cycle.
44
FAULTA
45
PWRGDA
47
50
3.3AUXOA
3.3AUXOB
51
PWRGDB
52
FAULTB
53
3.3GB
Slot B 3.3V Gate-Drive Output. Connect 3.3GB to the gate of slot B’s 3.3V MOSFET. At power-up,
V3.3GB is charged to 5.5V above the 3.3V supply by a constant current derived from V12VIN.
V3.3GB‘s rise time is determined by the external gate capacitance.
54
3.3SB-
Slot B 3.3V Negative Current-Sense Input. Connect to the negative side of the sense resistor using
the Kelvin-sensing technique to ensure accurate current sensing.
55
3.3SB+
Slot B 3.3V Positive Current-Sense Input. Connect the positive side of the current-sense resistor to
3.3SB+ using the Kelvin-sensing technique to ensure accurate current sensing.
56
12GB
Slot B 12V Gate-Drive Output. Connect 12GB to the gate of slot B’s 12V MOSFET. At power-up,
V12GB is raised to the internal charge-pump voltage level by a constant current.
Detailed Description
The MAX5957/MAX5958 triple hot-plug controllers are
designed for PCIe applications. The devices provide
hot-plug control for 12V, 3.3V, and 3.3V auxiliary supplies for three PCIe slots. The MAX5957/MAX5958s’
logic inputs/outputs allow interfacing directly with the
system hot-plug-management controller or through an
SMBus with an external I/O expander. An integrated
debounced attention switch and present-detect signals
are included to simplify system design (Figure 1).
The MAX5957/MAX5958 drive six external n-channel
MOSFETs to control the 12V and 3.3V main outputs.
The 3.3V auxiliary outputs are controlled through internal 0.2Ω n-channel MOSFETs. Internal charge pumps
provide a gate drive for the 12V outputs while the gate
drive of the 3.3V output is driven by the 12V input supply. The 3.3V auxiliary outputs are completely independent from the main outputs with their own charge
pumps.
______________________________________________________________________________________
13
MAX5957/MAX5958
Pin Description (continued)
MAX5957/MAX5958
Triple PCI Express, Hot-Plug Controllers
RTIM
RPORADJ
IN
PORADJ
TIM
OUT
12VIN
PWRGD_
FAULT_
12S_+
108mV
+
-
+
-
RSENSE
54mV
12S_-
CHARGE
PUMP
5µA
12G_
10µA
Aµ01
tFAULT
DEBOUNCE
FAST
OSCILLATOR
tPOR
OSCILLATOR
150µA
120mA
Aµ001
MAX5957
3.3S_+
40mV
+
-
+
-
RSENSE
20mV
3.3S_5µA
3.3G_
10µA
BIAS, REFERENCES,
AND UVLO
CONTROL LOGIC
MAIN-CHANNEL
CONTROL LOGIC
MAIN-CHANNEL
150µA
150mA
CONTROL LOGIC
AUX-CHANNEL
VREF
CONTROL LOGIC
AUX-CHANNEL
+
-
CHARGE
PUMP
UVLO
100µA
3.3AUXO
INPUT COMPARATOR AND
CHIP CONTROL LOGIC
ON_
AUXON_
FON_
PRES-DET_
Figure 1. Single-Channel Internal Block Diagram
14
______________________________________________________________________________________
Triple PCI Express, Hot-Plug Controllers
The power requirement for PCIe connectors is defined
by the PCIe card specification and summarized in
Table 1.
Startup
The main supply outputs can become active only after
all the following events have occurred:
• V3.3AUXIN is above its UVLO threshold.
• V 12VIN and V 3.3SA+ are both above their UVLO
threshold.
• ON_ is driven high.
• PRES-DET_ is low for more than 4ms.
The auxiliary supply output is made available only after
the following events have occurred:
• V3.3AUXIN is above its UVLO threshold.
• AUXON_ is driven high.
• PRES-DET_ is low for more than 4ms.
The FON_ input overrides all other control signals and
turns on the respective slot when driven low, as long as
the UVLO thresholds have been reached. Table 2 summarizes the logic conditions required for startup. The auxiliary supply input powers the internal control logic and
analog references of the MAX5957/MAX5958, so the main
supplies cannot be enabled, if V3.3VAUXIN is not present.
When an output is enabled, a programmable startup
timer (tSU) begins to count the startup time duration.
The value of tSU is set to 2x the fault timeout period
(tFAULT). RTIM externally connected from TIM to GND
sets the duration of tFAULT.
Table 1. Power Requirement for PCIe Connectors
POWER FAIL
X1 CONNECTOR
X4/8 CONNECTOR
X16 CONNECTOR
Voltage Tolerance
±9% (max)
±9% (max)
±9% (max)
Supply Current
3.0A (max)
3.0A (max)
3.0A (max)
1000µF (max)
1000µF (max)
1000µF (max)
Voltage Tolerance
±8% (max)
±8% (max)
±8% (max)
Supply Current
0.5A (max)
0.5A (max)
0.5A (max)
300µF (max)
1000µF (max)
2000µF (max)
±9% (max)
±9% (max)
±9% (max)
Supply Current, Wake Enabled
375mA (max)
375mA (max)
375mA (max)
Supply Current, Nonwake Enabled
20mA (max)
20mA (max)
20mA (max)
Capacitive Load
150µF (max)
150µF (max)
150µF (max)
3.3V
Capacitive Load
12V
Capacitive Load
3.3V AUXILIARY
Voltage Tolerance
______________________________________________________________________________________
15
MAX5957/MAX5958
At power-up, the MAX5957/MAX5958 keep all the
external MOSFETs off until all supplies rise above their
respective UVLO thresholds. These devices keep the
internal MOSFETs off only until the 3.3VAUXIN supply
rises above its UVLO threshold. Upon a turn-on command, the MAX5957/MAX5958 enhance the external
and internal MOSFETs slowly with a constant gate current to limit the power-supply inrush current. The
MAX5957/MAX5958 actively limit the current of all outputs at all times and shut down the corresponding
channel if an overcurrent condition persists for longer
than a resistor-programmable overcurrent timeout (see
the Fault Management section). Thermal protection circuitry also shuts down all outputs if the die temperature
exceeds +150°C. After an overcurrent or overtemperature fault condition, the MAX5957/MAX5958 latch off or
automatically restart after a restart time delay.
MAX5957/MAX5958
Triple PCI Express, Hot-Plug Controllers
Table 2. Control Logic Truth Table
PRES-DET
12V_ AND 3.3V_
OUTPUTS
3.3VAUXO_AUXILIARY
OUTPUTS
Low
X
On
On
High
High
Off
Off
Low*
Off
Off
FON_
ON_
AUXON_
X
X
X
X
Low
Low
High
High
Low
High
Low*
On
Off
Low
High
High
Low*
Off
On
High
High
High
Low*
On
On
*PRES-DET_ high-to-low transition has a 4ms delay (tDEG).
ON_
ON_, AUXON_
VON_,TH
VPGTH12
VPGTH3.3
12G_, 3.3G_
12VO_, 3.3VO_
VON_,TH
12G_
V12ILIM,TH
RSENSE
12V OUTPUT
CURRENT
3.3VAUXO_
3.3VAUXO_
VPGTH3.3AUX
tPOR_HL
PWRGD_
3.3AUXIN
RISING
EDGE
3.3VAUXIN
RISING
EDGE
2 x tFAULT
FAULT_
PWRGD_ IS PULLED UP TO 3.3.
FAULT_ IS PULLED UP TO 3.3AUXIN.
Figure 2. Power-Up Timing, No Fault
16
PWRGD_
FAULT_
PWRGD_ IS PULLED UP TO 3.3VAUXO_.
FAULT_ IS PULLED UP TO 3.3VAUXIN.
A FAULT ON THE 3.3V OUTPUT OR 3.3VAUXO_ OUTPUT PRODUCES SIMILAR RESULTS.
Figure 3. 12V Power-Up Timing (Turn-On into Output
Overcurrent/Short Circuit)
______________________________________________________________________________________
Triple PCI Express, Hot-Plug Controllers
Power-Good (PWRGD_)
12G_
V12ILIM,TH
RSENSE
12V OUTPUT
CURRENT
PWRGD_
tFAULT
Power-good (PWRGD_) is an open-drain output that
pulls low a time (tPOR_HL) after all the outputs of the
respective slot are fully on. All outputs are considered
fully on when 3.3G_ has risen to VPGTH3.3, 12G_ has
risen to V PGTH12 , and V 3.3AUXO_ is less than
VPGTH3.3AUX. tPOR_HL is adjustable from 2.4ms to 1.5s
by connecting a resistor from PORADJ to GND. See the
Setting the Power-On Reset and Timeout Period
(tPOR_HL) sections. Connect PORADJ to GND to completely skip the POR time delay for PWRGD_ assertion.
Thermal Shutdown
FAULT_
PWRGD_ IS PULLED UP TO 3.3VAUXO_.
FAULT_ IS PULLED UP TO 3.3VAUXIN.
A FAULT ON THE 3.3V OUTPUT OR 3.3VAUXO_ OUTPUT PRODUCES SIMILAR RESULTS.
Figure 4. 12 Output Overcurrent/Short Circuit During Normal
Operation
12V and 3.3V Outputs Normal Operation
The MAX5957/MAX5958 monitor and actively limit the
current of the 12V and 3.3V outputs after the startup
period. Each output has its own overcurrent threshold.
If any of the monitored output currents rise above the
overcurrent threshold for a period t FAULT , FAULT_
asserts and the controller disengages both the 12V and
3.3V outputs for the particular slot (see the Fault
Management section).
3.3V Auxiliary Output Normal Operation
The auxiliary output current is internally monitored and
actively limited to the maximum current-limit value. An
overcurrent fault condition occurs when the output current exceeds the overcurrent threshold for longer than
tFAULT. A fault on an auxiliary channel causes all supplies of the affected channel to be disabled after a programmable time period tFAULT.
A fault condition on a main channel (V12VIN or V3.3VIN)
causes all the channel’s main outputs to shut down
after the tFAULT period and then either latch off or automatically restart after the tRESTART (tRESTART = 64 x
tFAUALT) period, depending on the device version. A
When the die temperature goes above (TSD) +150°C, an
overtemperature fault occurs and the MAX5957/
MAX5958 shut down all outputs. The devices wait for the
junction temperature to decrease below TSD - hysteresis
before entering fault management (see the Fault
Management section).
Fault Management
A fault occurs when an overcurrent or 12G_ or 3.3G_
below the power-good threshold lasts longer than
tFAULT or when the device experiences an overtemperature condition:
• A fault on a main output (12V or 3.3V) shuts down
both main outputs of the respective slot. The 3.3V
auxiliary is not affected.
• A fault on the 3.3V auxiliary output shuts down all
three outputs of the respective slot.
The MAX5957A/MAX5958A automatically restart from a
fault shutdown after the t RESTART period while the
MAX5957L/MAX5958L latch off. If an overcurrent fault
occurred on a main output, bring ON_ low for at least
tRESET (100µs) and high again to reset the fault and
restart the outputs. If the overcurrent fault occurred on
an auxiliary output or an overtemperature fault
occurred, bring both ON_ and AUXON_ low for a minimum of tRESET to reset the fault. Toggle ON_ or only
AUXON_ to reset the fault condition. If ON_ and
AUXON are toggled before tRESTART time counting has
elapsed, the MAX5957L/MAX5958L store the information and restart when the delay is finished. The
MAX5957A/MAX5958A (autoretry versions) restart all
channels automatically after tRESTART.
______________________________________________________________________________________
17
MAX5957/MAX5958
fault on any of the channel’s main outputs does not
affect the auxiliary channel (V3.3AUXIN).
MAX5957/MAX5958
Triple PCI Express, Hot-Plug Controllers
Debounced Logic Gate
(INPUT_ and OUTPUT_)
INPUT1, INPUT2, and INPUT3 accept inputs from
mechanical switches. The corresponding outputs are
OUTPUT1, OUTPUT2, and OUTPUT3. OUTPUT_ is
debounced for 4ms. When INPUT_ goes from high to
low, OUTPUT_ goes low immediately and stays low for
at least 4ms. After the debounce time, OUTPUT_ follows INPUT_. If INPUT_ goes from low to high, OUTPUT_ goes high immediately and stays high for at least
4ms. After the debounce time, OUTPUT_ follows
INPUT_. Figure 5 shows the timing diagram describing
the INPUT_/OUTPUT_ debounced feature.
Present-Detect and Forced-On Inputs
(PRES-DET_, FON_)
PRES-DET_ input detects the PRSNT#2 pin on a PCIe
connector. When the card is plugged in, PRES-DET_
goes low and allows the turn-on of the outputs of the
respective slot after a 4ms debounced time. When the
card is removed, an internal 50kΩ pullup resistor forces
PRES-DET_ high and the respective slot is shut down
with no delay. PRES-DET_ works in conjunction with
ON_ and AUXON_ and only enables the device when
ON_ and AUXON_ are high.
A logic-low on FON_ forces the respective slot (main
supplies and auxiliary) to turn on regardless of the status of the other logic inputs, provided the UVLO thresholds are exceeded on all the inputs.
INPUT
tDBC
tDBC
tDBC
DEBOUNCED
OUTPUT
Active Current Limits
Active current limits are provided for all three outputs of
the three slots (slot A, slot B, and slot C). Connect a
current-sense resistor between 12S_+ and 12S_- to set
the current limit for the 12V outputs. The current limit is
set to 54mV / RSENSE12. Connect a current-sense resistor between 3.3S_+ and 3.3S_- to set the current limit
for the 3.3V main outputs to 20mV / RSENSE3.3. For the
auxiliary output (3.3VAUXO_) the current limit is fixed at
450mA in the MAX5957 and 700mA in the case of the
MAX5958.
When the voltage across R SENSE12 or R SENSE3.3
reaches the current-limit threshold voltage, the
MAX5957/MAX5958 regulate the gate voltage to maintain the current-limit threshold voltage across the sense
resistor. If the current limit lasts for tFAULT, then an
overcurrent fault occurs. The MAX5957/MAX5958 shut
down both the 12V and 3.3V outputs and assert the
FAULT_ output of the respective slot.
When the auxiliary output reaches the current limit for
longer than tFAULT, a fault occurs and the device shuts
down all outputs and asserts FAULT of the respective slot.
UVLO Threshold
The UVLO thresholds prevent the internal auxiliary
MOSFETs and the external main channel MOSFETs
from turning on if V12VIN, V3.3VIN, and V3.3VAUXIN are
not present. Internal comparators monitor the main
supplies and the auxiliary supply and keep the gatedrive outputs (12GA, 12GB, 12GC, 3.3GA, 3.3GB, and
3.3GC) low until the supplies rise above their UVLO
threshold. The 12V main supply is monitored at 12VIN
and has a UVLO threshold of 10V. The 3.3V main supply is monitored at 3.3SA+ and has a UVLO threshold
of 2.65V. The auxiliary supply is monitored at
3.3AUXIN and has a 2.65V UVLO threshold. For either
main channels to operate, V3.3AUXIN must be above
its UVLO threshold.
Figure 5. INPUT_ and OUTPUT_ Debounced Feature
18
______________________________________________________________________________________
Triple PCI Express, Hot-Plug Controllers
N
LATCH-OFF
OPTION?
MAX5957/MAX5958
SHUT DOWN
12V AND 3.3V OUTPUTS.
ASSERT FAULT_
STAY WAITING FOR
tRESTART
N
FAULT
STILL PRESENT?
Y
Y
RESET tFAULT
COUNTER
N
N
N
ON_ TOGGLED
HIGH ≥ LOW ≥ HIGH
Y
Y
START COUNTING
tFAULT
tFAULT ELAPSED?
Y
N
RESET FAULT_
3.3VAUXIN IS OK,
AUXON_ IS HIGH,
PRES_DET IS LOW
ARE ALL
MAIN OUTPUTS OK?
NO FAULT
DETECTED
Y
FAULT ON 12V
OR 3.3V OUTPUTS
Y
ENABLE CHARGE
ON 3.3G_ AND 12G_.
START
COUNTING tSU
Y
MAIN INPUTS ARE
OK, ON_ IS HIGH
tSU
ELAPSED?
N
N
N
ON_ AND
AUXON_ TOGGLED
HIGH ≥ LOW
≥ HIGH
ALL PGOOD
THRESHOLDS
REACHED?
START PGOOD
THRESHOLD
MONITORING
N
ASSERT PWRGD_
AFTER tPOR_HL
DELAY
Y
Y
RESET PWRGD_
RESET FAULT_
POWER ON
AUXILIARY OUTPUT.
FAULT_ AND PWRGD_ ARE
HIGH IMPEDANCE
ENABLE CHARGE ON
INTERNAL AUXILIARY
MOSFET DRIVING 3.3AUXO_.
START COUNTING tSU
tSU
ELAPSED?
Y
AUX OUTPUT OK?
NO FAULT DETECTED
Y
N
N
N
Y
LATCH-OFF
OPTION?
SHUT DOWN ALL OUTPUTS.
ASSERT FAULT_.
STAY WAITING
FOR tRESTART
Y
N
START COUNTING
tFAULT
tFAULT ELAPSED?
Y
N
FAULT
STILL PRESENT?
N
FAULT ON 3.3AUXO_?
Y
RESET tFAULT
COUNTER
Figure 6. Fault Management Flowchart
______________________________________________________________________________________
19
MAX5957/MAX5958
Triple PCI Express, Hot-Plug Controllers
External MOSFET Gate Drivers
(12G_ and 3.3G_)
The gate drive for the external MOSFETs is provided at
12GA, 12GB, 12GC, 3.3GA, 3.3GB, and 3.3GC. 12G_
is the gate drive for the 12V main supply and is boosted to 5.3V above V12VIN by its internal charge pump.
During turn-on, 12G_ sources 5µA into the external
gate capacitance to control the turn-on time of the
external MOSFET. During turn-off, 12G_ sinks 150µA
from the external gate capacitance to quickly turn off
the external MOSFET. During short-circuit events, an
internal 120mA current sink activates to rapidly bring
the load current into the regulation limits.
3.3G_ is the gate drive for the 3.3V main supply’s MOSFET and is driven to 5.5V above the 3.3V main supply.
The power for 3.3G_ is supplied from 12VIN and has no
internal charge pump. During turn-on, 3.3G_ sources
5µA into the external gate capacitance to control the
turn-on time of the external MOSFET. During turn-off,
3.3G_ sinks 150mA to quickly turn off the external
MOSFET. During short-circuit events, an internal
120mA current sink activates to rapidly turn off the
appropriate external MOSFET.
Auxiliary Supply (3.3VAUXIN)
3.3VAUXIN provides power to the auxiliary outputs as
well as the internal logic and references. The drains of
the internal auxiliary MOSFETs connect to 3.3AUXIN
through internal sense resistors and the sources connect to the auxiliary outputs (3.3VAUXO_). Both
MOSFETs have typical on-resistance of 0.2Ω. Each
channel’s internal charge pump boosts the gate-drive
voltage to fully turn on the internal n-channel MOSFETs.
The auxiliary supplies have an internal current limit set
to 450mA (MAX5957), 700mA (MAX5958).
Applications Information
Setting the Power-On Reset
tFAULT is the time an overcurrent or overtemperature
fault must remain for the MAX5957/MAX5958 to disable
the main or auxiliary channels of a particular slot.
Program the fault timeout period (tFAULT) by connecting a resistor (RTIM) from TIM to GND. tFAULT can be
calculated by the following equation:
20
tFAULT = (166ns / Ω) x RTIM
The tFAULT programmed time duration must be chosen
according to the total capacitance load connected to
the 12G_ and 3.3G_ pins. To properly power up the
main supply outputs, the following constraints need to
be taken:
tSU ≥ (VGATE x CLOAD) / ICHG
where tSU = 2 x tFAULT and where:
• ICHG = 5µA.
• VGATE = 4.8V + V12VIN for 12G_ and VGATE = 6.8V
+ V3.3VIN for 3.3G_.
• CLOAD is the total capacitance load at the gate.
Maximum and minimum values for RTIM are 500Ω and
500kΩ, respectively. Leave TIM floating for a default
tFAULT of 10ms.
Timeout Period (tPOR_HL)
tPOR_HL is the time from when the gate voltages of all
outputs of a slot reach their power-good threshold to
when PWRGD_ pulls low. Program the POR timeout
period (tPOR) by connecting a resistor (RPORADJ) from
PORADJ to GND. tPOR_HL can be calculated by the following equation:
tPOR_HL = (2.5µs / Ω) x RPORADJ
Maximum and minimum values for RPORADJ are 500Ω
and 500kΩ, respectively. Leave PORADJ floating for a
default tPOR of 150ms. Connect PORADJ to GND in
order to completely skip the power-on delay time prior
to the PWRGD_ assertion.
Component Selection
Select the external n-channel MOSFET according to the
applications current requirement. Limit the switch
power dissipation by choosing a MOSFET with an
RDS_ON low enough to have a minimum voltage drop at
full load. High RDS_ON causes larger output ripple if
there are pulsed loads. High RDS_ON can also trigger
an external undervoltage fault at full load. Determine
the MOSFET’s power-rating requirement to accommodate a short-circuit condition on the board during startup. Table 3 lists the MOSFETs and sense resistor
manufacturers.
______________________________________________________________________________________
Triple PCI Express, Hot-Plug Controllers
COMPONENT
Sense Resistor
MOSFETs
MANUFACTURER
PHONE
WEBSITE
Vishay-Date
402-564-3131
www.vishay.com
IRC
704-264-8861
www.irctt.com
Fairchild
888-522-5372
www.fairchildsemi.com
International Rectifier
310-322-3331
www.irf.com
Motorola
602-244-3576
www.mot-sps.com/ppd
—
www.vishay.com
Vishay-Siliconix
Additional External Gate Capacitance
Input Transients
External capacitance can be added from the gate of
the external MOSFETs to GND to slow down the dV/dt
of the 12V and 3.3V outputs. The maximum gate
capacitance load at 12G_ and 3.3G_ must be consistent with the conditions described in the Setting the
Power-On Reset section.
The 12V input (12VIN), the 3.3V input (3.3SA+), and the
3.3V auxiliary (3.3AUXIN) must be above their UVLO
thresholds before startup can occur. Input transients
can cause the input voltage to sag below the UVLO
threshold. The MAX5957/MAX5958 reject transients on
the input supplies that are shorter than 4µs (typ).
Because some load fault conditions can cause voltage
transients to propagate to the supply inputs with duration of greater than 4µs, it is recommended that a small
Schottky diode be placed in series with the 12VIN pin
connection, upstream of the 1µF bypass capacitor. This
provides a hold-up supply that will prevent the 12VIN
input from dropping below V12UVLO during severe transients. See the Typical Application Circuit.
Maximum Load Capacitance
Large capacitive loads at the 12V output, the 3.3V output, and the 3.3V auxiliary output can cause a problem
when inserting discharged PCI cards into live backplanes. A fault occurs if the time needed to charge the
capacitance of the board is greater than the typical
startup time (2 x tFAULT). The MAX5957/MAX5958 withstand large capacitive loads due to their adjustable
startup times and adjustable current-limit thresholds.
Calculate the maximum load capacitance as follows:
CLOAD < (tSU x ILIM) / VOUT
VOUT is either the 3.3V output, the 12V output, or the
3.3V auxiliary output for slot A, slot B, or slot C.
______________________________________________________________________________________
21
MAX5957/MAX5958
Table 3. Component Manufacturers
Triple PCI Express, Hot-Plug Controllers
MAX5957/MAX5958
Typical Application Circuit
ONE OF THREE SLOTS SHOWN
PCI EXPRESS
SLOT_
V12VMAIN
V3.3VAUX
PRSNT1#
R1
8mΩ
+12V
0.1µF
2.2µF
IN5819
RTIM =
OPEN
RPORADJ =
OPEN
12G_
GND
12S_+
12S_-
3.3VAUXIN
TIM
PWRGD_
PWRGD
MAX5957
MAX5958
10kΩ
3.3VAUX
PORADJ
12VIN
3.3VAUXO_
GND
3.3G_
3.3S_-
3.3S_+
PRES-DET_
FAULT_
FON_
AUXON_
ON_
INPUT_
OUTPUT_
V3.3VMAIN
0.1µF
R2
5mΩ
+3.3V
ATTENTION
SWITCH
V3.3VAUXIN
10kΩ
PRSNT2#
MRL
MAX7313ATG
LEDs
16-BIT I/O
EXPANDER
2
SMBus
22
2
AO–A2
______________________________________________________________________________________
INT
Triple PCI Express, Hot-Plug Controllers
N.C.
PRES-DETB
FONB
PRES-DETA
FONA
OUTPUT3
INPUT3
ONA
AUXONA
12SA+
12SA-
12GA
3.3SA+
3.3SA-
TOP VIEW
42 41 40 39 38 37 36 35 34 33 32 31 30 29
28 12VIN
3.3GA 43
27 GND
FAULTA 44
26 PORADJ
PWRGDA 45
25 TIM
PGND 46
3.3AUXOA 47
24 PGND
3.3AUXIN 48
23 3.3VAUXIN
22 3.3AUXOC
3.3AUXIN 49
MAX5957
MAX5958
3.3AUXOB 50
PWRGDB 51
21 PWRGDC
20 FAULTC
FAULTB 52
19 3.3GC
3.3GB 53
18 3.3SC17 3.3SC+
3.3SB- 54
3.3SB+ 55
16 12GC
+
15 12SC-
12SB+
AUXONB
ONB
INPUT1
OUTPUT1
INPUT2
8
9
10 11 12 13 14
12SC+
7
AUXONC
6
ONC
5
PRES-DETC
4
FONC
3
GND
2
OUTPUT2
1
12SB-
12GB 56
THIN QFN
Chip Information
PROCESS: BiCMOS
______________________________________________________________________________________
23
MAX5957/MAX5958
Pin Configuration
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
E
DETAIL A
32, 44, 48L QFN.EPS
MAX5957/MAX5958
Triple PCI Express, Hot-Plug Controllers
(NE-1) X e
E/2
k
e
D/2
C
L
(ND-1) X e
D
D2
D2/2
b
L
E2/2
C
L
k
E2
C
L
C
L
L
L
e
A1
A2
e
A
PACKAGE OUTLINE
32, 44, 48, 56L THIN QFN, 7x7x0.8mm
21-0144
24
______________________________________________________________________________________
F
1
2
Triple PCI Express, Hot-Plug Controllers
PACKAGE OUTLINE
32, 44, 48, 56L THIN QFN, 7x7x0.8mm
21-0144
F
2
2
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 ____________________ 25
© 2007 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
MAX5957/MAX5958
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)