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19-0884; Rev 0; 7/07
Triple PCI Express, Hot-Plug Controllers
General Description
The MAX5957/MAX5958 triple hot-plug controllers are designed for PCI Express (PCIe)(R) 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 SMBusTM 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 0.2 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 -40C to +85C temperature range. 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
Features
MAX5957/MAX5958
Ordering Information
PART MAX5957AETN+ MAX5957LETN+ MAX5958AETN+ MAX5958LETN+ TEMP RANGE -40C to +85C -40C to +85C -40C to +85C -40C to +85C PINPACKAGE 56 Thin QFN 56 Thin QFN 56 Thin QFN 56 Thin QFN PKG CODE T5677-1 T5677-1 T5677-1 T5677-1
Applications
Servers Desktop Mobile Server Platforms Workstations Embedded Devices
+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 MAX5957AETN+ MAX5957LETN+ MAX5958AETN+ MAX5958LETN+ LATCH OFF AUTORESTART GUARANTEED AUX CURRENT (mA) 375 375 550 550
________________________________________________________________ Maxim Integrated Products
1
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.
Triple PCI Express, Hot-Plug Controllers MAX5957/MAX5958
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 = +70C) 56-Pin Thin QFN (derate 40mW/C above +70C) .....3200mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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 = -40C to +85C, unless otherwise noted. Typical values are at TA = TJ = +25C.) (Note 1)
PARAMETER 12V SUPPLY (MAIN) 12V Supply Input-Voltage Range 12V Undervoltage Lockout 12V Undervoltage Lockout Deglitch Time 12V Supply Current 12VIN CONTROL 12VIN Current-Limit Threshold (V12S+ - V12S-) 12G_ Gate Charge Current V12ILIM I12G, CHG V12G_ = GND Normal turn-off, ON_ = GND, V12G_ = 2V 12G_ Gate Discharge Current I12G_, DIS Output short-circuit condition, strong gate pulldown to regulation, (V12S+ - V12S-) 1V, V12G_ = 5V I12G_ = 1A Referred to V12VIN, I12G_ = 1A (Note 2) 49 4 50 54 5 150 59 6 250 mV A A V12VIN V12UVLO tDEG,UVLO I12VIN V12VIN rising Hysteresis V12IN falling below V12UVLO to UVLO assertion V12VIN = 13.2V 10.8 9.5 12 10 0.1 30 1 2.5 13.2 10.5 V V s mA SYMBOL CONDITIONS MIN TYP MAX UNITS
60
120
200
mA
12G_ Gate High Voltage (V12G_ - V12VIN) 12G_ Threshold Voltage for PWRGD_ Assertion 12S_- Input Bias Current 12S_+ Input Bias Current 3.3V SUPPLY (MAIN) 3.3V Supply Voltage Range Undervoltage Lockout (Note 3)
V12G, H VPGTH12
4.8 3.0
5.3 4.0
5.8 4.8 1
V V A A V V mV
10 V3.3S_+ 3.3SA+ rising Hysteresis 3.0 2.50 3.3 2.65 30
30 3.6 2.78
2
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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 = -40C to +85C, unless otherwise noted. Typical values are at TA = TJ = +25C.) (Note 1)
PARAMETER 3.3V CONTROL 3.3V Current-Limit Threshold (V3.3S_+ - V3.3S_-) 3.3G_ Gate Charge Current V3.3ILIM I3.3G_,CHG V3.3G_ = GND Normal turn-off, ON_ = GND, V3.3G_ = 2V 3.3G_ Gate Discharge Current I3.3G_, DIS Output short-circuit condition, strong gate pulldown to regulation, V3.3S_+ - V3.3S_- 1V, V3.3G- = 5V ISOURCE = 1A Referred to V3.3AUXIN, I3.3G_ = 1A (Note 2) 17 4 50 20 5 150 23 6 250 mV A A SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX5957/MAX5958
90
150
250
mA
3.3G_ Gate High Voltage (V3.3G_- V3.3S_+) 3.3G_ Threshold Voltage for PWRGD_ Assertion 3.3S_- Input Bias Current 3.3S_+ Input Bias Current 3.3V AUXILIARY SUPPLY 3.3VAUXIN Supply Input 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 (V3.3VAUXIN - V3.3VAUXO) 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
V3.3G_H VPGTH3.3
4.5 3.0
5.5 4.0
6.8 4.5 1
V V A A
20
60
V3.3AUXIN V3.3VAUXUVLO V3.3VAUXIN rising Hysteresis V3.3VAUXIN = 3.6V I3.3VAUXO = 375mA (MAX5957) I3.3VAUXO = 550mA (MAX5958) 3.3VAUXO_ shorted to GND VPGTH3.3AUX (Note 2) MAX5957 MAX5958
3.0 2.50
3.3 2.65 30 2.5
3.6 2.78 5 225 280
V V mV mA mV mA
376 560
450 700
564 850 400
mV
Rising edge Hysteresis
1.0 25
2.0
V mV
1 25 50 4 75
A k s
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Triple PCI Express, Hot-Plug Controllers MAX5957/MAX5958
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 = -40C to +85C, unless otherwise noted. Typical values are at TA = TJ = +25C.) (Note 1)
PARAMETER PRES-DET_ High-to-Low Deglitch Time SYMBOL tDEG VPORADJ = GND PWRGD_ Power-On Reset Deglitch Time (Note 2) PORADJ = unconnected tPOR_HL RPORADJ = 20k RPORADJ = 100k RPORADJ = 200k PWRGD_ Low-to-High Deglitch Time PWRGD_, FAULT_ Output Low Voltage PWRGD_, FAULT_ Output High Leakage Current tPOR_LH ISINK = 2mA ISINK = 30mA PWRGD_, FAULT_ = 5.5V TIM = open FAULT_ Timeout tFAULT RTIM = 15k RTIM = 120k RTIM = 300k FAULT_ Timeout During Startup tSU 5.5 1.4 12 11 2.6 22 53 2x tFAULT 64 x tFAULT (Note 4) TJ rising 2.6 ISOURCE = 2mA ISINK = 2mA V3.3AUXIN - 0.3 100 150 20 tDBC 4.4 6.2 V3.3AUXIN 0.4 ms 90 35 145 160 55 265 530 4 0.1 0.8 1 17 3.8 32 ms s V A CONDITIONS MIN 3 TYP 5 MAX 7 1 250 75 380 ms UNITS ms s
Autorestart Delay Time Fault Reset Minimum Pulse Width Thermal Shutdown Threshold Thermal Shutdown Hysteresis OUT_ Debounce Time OUT_ Voltage High OUT_ Voltage Low
tRESTART tRESET tSD
ms s C ms V V
Note 1: Note 2: Note 3: Note 4:
All devices are 100% production tested at TA = +25C. 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.
4
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Triple PCI Express, Hot-Plug Controllers
Typical Operating Characteristics
(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 INPUT SUPPLY CURRENT vs. TEMPERATURE
MAX5957 toc01
MAX5957/MAX5958
3.3VAUXIN SUPPLY CURRENT vs. TEMPERATURE
4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0
MAX5957 toc02
ON_ AND AUXON_ LOW-TO-HIGH THRESHOLD VOLTAGE vs. TEMPERATURE
1.55 THRESHOLD VOLTAGE (V) 1.50 1.45 1.40 1.35 1.30 1.25 1.20 AUXON_ THRESHOLD ON_ THRESHOLD
MAX5957 toc03
1.10 1.08 1.06 SUPPLY CURRENT (mA) 1.04 1.02 1.00 0.98 0.96 0.94 0.92 0.90 -40 -15 10 35 60
5.0 3.3VAUXIN SUPPLY CURRENT (mA)
1.60
85
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (C)
TEMPERATURE (C)
TEMPERATURE (C)
3.3VAUXO_ OUTPUT VOLTAGE vs. OUTPUT CURRENT
MAX5957 toc04
12G_ AND 3.3G_ GATE CHARGE CURRENT vs. TEMPERATURE
5.15 GATE CHARGE CURRENT (A) 5.10 5.05 5.00 4.95 4.90 4.85 4.80 4.75 150 -40 -15 10 35 60 85 -40 3.3G_ 12G_
MAX5957 toc05
12G_ AND 3.3G_ GATE DISCHARGE CURRENT vs. TEMPERATURE
MAX5957 toc06
4.0 3.5 OUTPUT VOLTAGE (V) 3.0 MAX5957 2.5 2.0 1.5 1.0 0.5 0 0 MAX5958
5.20
180 GATE DISCHARGE CURRENT (A) 175 170 165 160 12G_ 155 3.3G_
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 OUTPUT CURRENT (A)
-15
10
35
60
85
TEMPERATURE (C)
TEMPERATURE (C)
3.3VAUX INTERNAL SWITCH MAXIMUM DROPOUT vs. TEMPERATURE
12V AND 3.3V CURRENT-LIMIT THRESHOLD (mV) 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 85 TEMPERATURE (C) ILOAD = 375mA MAX5957
MAX5957 toc07
12V AND 3.3V CURRENT-LIMIT THRESHOLD VOLTAGE vs. TEMPERATURE
MAX5957 toc08
AUXILIARY CURRENT LIMIT vs. TEMPERATURE
0.90 AUXILIARY CURRENT (mA) 0.80 0.70 0.60 0.50 0.40 0.30 0.20 0.10 MAX5957 MAX5958
MAX5957 toc09
0.20 ILOAD = 550mA MAX5958
60 50 40 30 20 10 0 -40 -15 10 35 60 3.3V CURRENT-LIMIT THRESHOLD
1.00
12V CURRENT-LIMIT THRESHOLD
0 85 -40 -15 10 35 60 85 TEMPERATURE (C) TEMPERATURE (C)
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Triple PCI Express, Hot-Plug Controllers 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.)
12V UNDERVOLTAGE LOCKOUT THRESHOLD vs. TEMPERATURE
MAX5957 toc10
3.3VAUXON UNDERVOLTAGE LOCKOUT THRESHOLD vs. TEMPERATURE
2.68 2.66 UVLO THRESHOLD (V) 2.64 2.62 2.60 2.58 2.56 2.54 2.52 2.50 5V/div 5V/div 20V/div
MAX5957 toc11
12V TURN-ON/TURN-OFF TIME
MAX5957 toc12
10.20 10.15 UVLO THRESHOLD (V) 10.10 10.05 10.00 9.95 9.90 9.85 9.80 -40 -15 10 35 60
2.70
10V/div
12V OUTPUT VOLTAGE 12G_
ON_
PWRGD_
85
-40
-15
10
35
60
85
40ms/div
TEMPERATURE (C)
TEMPERATURE (C)
3.3V TURN-ON/TURN-OFF TIME
MAX5957 toc13
3.3V AUXILIARY TURN-ON/TURN-OFF TIME
MAX5957 toc14
3.3V OUTPUT 5V/div 3.3G_ 10V/div
3.3AUXO_OUTPUT VOLTAGE 2V/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
MAX5957 toc15
FAULT CONDITION ON 12V MAIN OUTPUT (AUTORESTART OPTION)
MAX5957 toc16
RLOAD STEP TO 1.5 5V/div 3.3VAUXO_ OUTPUT VOLTAGE 3.3 INPUT, 3.3VAUXIN 0V 5V/div 5V/div 10V/div 3.3 OUTPUT VOLTAGE PWRGD 3.3G_ 0V 4ms/div 100ms/div 0V tRESTART 0A
12V OUTPUT CURRENT 5A/div 12G_ 20V/div 12V OUTPUT VOLTAGE 10V/div
5V/div
FAULT_ 5V/div
6
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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 3.3V MAIN OUTPUT (AUTORESTART OPTION)
MAX5957 toc17
MAX5957/MAX5958
FAULT CONDITION ON AUXILIARY OUTPUT (AUTORESTART OPTION)
MAX5957 toc18
RLOAD STEP TO 0.5 3.3V MAIN OUTPUT CURRENT 2A/div 0A 0V 3.3G_ 10V/div 3.3V OUTPUT VOLTAGE 5V/div tRESTART 0V 100ms/div FAULT_ 5V/div
RLOAD STEP TO 4 3.3VAUXO_ OUTPUT CURRENT 500mA/div 0A 3.3VAUXO_ OUTPUT VOLTAGE 2V/div 0V
0V
tRESTART
FAULT_ 2V/div 0V
100ms/div
FAULT CONDITION ON 12V OUTPUT (LATCH OPTION MAX5958)
MAX5957 toc19
FAULT CONDITION ON 12V OUTPUT
MAX5957 toc20
RLOAD STEP TO 1.5
12V OUTPUT CURRENT 5A/div
RLOAD STEP TO 1.5
tFAULT
12V OUTPUT CURRENT 5A/div
12G_ 20V/div 12V OUTPUT VOLTAGE 10V/div
12G_ 20V/div 12V OUTPUT VOLTAGE 10V/div
FAULT_ 5V/div 100ms/div 4ms/div
FAULT_ 5V/div
FAULT CONDITION ON 3.3V OUTPUT (LATCHOFF OPTION)
MAX5957 toc21
FAULT CONDITION ON 3.3V MAIN OUTPUT
MAX5957 toc22
RLOAD STEP TO 0.5 3.3V OUTPUT CURRENT 2A/div tFAULT
RLOAD STEP TO 0.5
3.3V OUTPUT CURRENT 2A/div
3.3G_ 10V/div 3.3V OUTPUT VOLTAGE 5V/div FAULT_ 5V/div 40ms/div 4ms/div
3.3G_ 10V/div 3.3V OUTPUT VOLTAGE 5V/div FAULT_ 5V/div
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7
Triple PCI Express, Hot-Plug Controllers 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.)
FAULT CONDITION ON AUXILIARY OUTPUT (LATCHOFF OPTION)
MAX5957 toc23
FAULT CONDITION ON AUXILIARY OUTPUT
MAX5957 toc24
RLOAD STEP TO 3.5
3.3VAUXO_ OUTPUT CURRENT 500mA/div
RLOAD STEP TO 3 tFAULT
3.3VAUXO_ OUTPUT CURRENT 500mA/div
3.3VAUXO_ OUTPUT VOLTAGE 2V/div MAX5958 FAULT_ 2V/div 100ms/div 10ms/div MAX5958
3.3VAUXO_ OUTPUT VOLTAGE 2V/div
FAULT_ 2V/div
SHORT CIRCUIT ON 12V MAIN OUTPUT
MAX5957 toc25
SHORT CIRCUIT ON 12V MAIN OUTPUT
MAX5957 toc26
12V OUTPUT CURRENT 5A/div
12V OUTPUT CURRENT 10A/div
12G_ 20V/div 0V 12V OUTPUT VOLTAGE 10V/div 0V 0V 12G_ 20V/div 12V OUTPUT VOLTAGE 10V/div FAULT_ 5V/div 4s/div
FAULT_ 5V/div 2ms/div
SHORT CIRCUIT ON 3.3V MAIN OUTPUT
MAX5957 toc27
SHORT CIRCUIT ON 3.3V MAIN OUTPUT
MAX5957 toc28
3.3V OUTPUT CURRENT 2A/div
3.3V OUTPUT CURRENT 10A/div
3.3G_ 5V/div 3.3V OUTPUT VOLTAGE 5V/div FAULT_ 5V/div 2ms/div 2s/div
3.3G_ 5V/div 3.3V OUTPUT VOLTAGE 5V/div FAULT_ 5V/div 0V
8
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Triple PCI Express, Hot-Plug Controllers 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.)
SHORT CIRCUIT ON 3.3AUXO_ AUXILIARY OUTPUT
MAX5957 toc29
SHORT CIRCUIT ON 3.3VAUXO_ AUXILIARY OUTPUT
MAX5957 toc30
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 MAX5958 4s/div
FAULT_ 5V/div MAX5958 2ms/div
POWER-UP INTO FAULT (AUXILIARY SUPPLY)
MAX5957 toc31
POWER-UP INTO FAULT (3.3V MAIN)
MAX5957 toc32
RLOAD = 3 tSU 3.3VAUXO_ OUTPUT CURRENT 500mA/div 3.3VAUXO_ OUTPUT VOLTAGE 2V/div 5A/div 3.3V OUTPUT CURRENT 3.3G_ 3.3V OUTPUT VOLTAGE ON_, AUXON_ FAULT_ 4ms/div
5V/div 2V/div
AUXON_ 5V/div FAULT_ 5V/div 4ms/div
5V/div 5V/div
MAX5958
POWER-UP INTO FAULT (12V MAIN OUTPUT)
MAX5957 toc33
PRESENT-DETECT (ON/OFF) OPERATION
MAX5957 toc34
tSU
12V OUTPUT CURRENT 5A/div 12G_ 10V/div 12V OUTPUT VOLTAGE 10V/div ON_, AUXON_ 5V/div FAULT_ 5V/div
10V/div
12V OUTPUT VOLTAGE
5V/div
3.3VAUXO_ OUTPUT VOLTAGE PWRGD_ PRES-DET_
5V/div 5V/div
4ms/div
40ms/div
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9
Triple PCI Express, Hot-Plug Controllers 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.)
PRESENT-DETECT (ON/OFF) OPERATION
MAX5957 toc35
FORCED-ON (ON/OFF) OPERATION
MAX5957 toc36
10V/div
12V OUTPUT VOLTAGE
10V/div
12V OUTPUT VOLTAGE
5V/div
3.3V OUTPUT VOLTAGE PWRGD_ PRES-DET_
5V/div
3.3V AUXO_ OUTPUT VOLTAGE PWRGD_ FON_
5V/div 5V/div
5V/div 5V/div
4ms/div
40ms/div
FORCED-ON (ON/OFF) OPERATION
MAX5957 toc37
DEBOUNCED INPUT/OUTPUT OPERATION
MAX5957 toc38
10V/div
12V OUTPUT VOLTAGE
INPUT_ 2V/div
5V/div
3.3V OUTPUT VOLTAGE PWRGD_ FON_ OUTPUT_ 2V/div
5V/div 5V/div
4ms/div
10ms/div
POWER-ON-RESET TIME vs. PORADJ RESISTOR
2400 2200 2000 1800 1600 1400 1200 1000 800 600 400 200 0 RPORADJ (k)
MAX5957 toc39
tFAULT TIME DELAY vs. TIM RESISTOR
180 160 140 tFAULT (ms) 120 100 80 60 40 20 0
MAX5957 toc40
200
tPOR_HL (ms)
0 100 200 300 400 500 600 700 800 900 1000
0
200
400
600
800
1000
RTIM (k)
10
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Triple PCI Express, Hot-Plug Controllers
Pin Description
PIN 1 2 3 4 5 6 7 8 9, 27 10 NAME 12SB12SB+ AUXONB ONB INPUT1 OUTPUT1 INPUT2 OUTPUT2 GND FONC FUNCTION 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. 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. Slot B 3.3V Auxiliary Output Enable. A logic-high at AUXONB turns on the slot B auxiliary output. 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). Digital Logic Gate Input 1 Digital Output One. 4ms debounced digital output of INPUT1. Digital Logic Gate Input 2 Digital Output 2. 4ms debounced digital output of INPUT2. Ground Slot C Forced-On Input. FONC has a 50k 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. Slot C Present-Detect Input. PRES-DETC accepts inputs from PRSNT-# on a PCIe connector. PRESDETC has an internal 50k 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. 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). Slot C 3.3V Auxiliary Output Enable. A logic-high at AUXONC turns on the slot C auxiliary output. 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. 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. 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. 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. 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. 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. 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. 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.
MAX5957/MAX5958
11
PRES-DETC
12 13 14 15 16 17 18
ONC AUXONC 12SC+ 12SC12GC 3.3SC+ 3.3SC-
19
3.3GC
20
FAULTC
21
PWRGDC
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Triple PCI Express, Hot-Plug Controllers MAX5957/MAX5958
Pin Description (continued)
PIN 22 NAME 3.3AUXOC Slot C 3.3V Auxiliary Power-Supply Output 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 0.1F capacitor to GND. Power Ground. Connect externally to GND. Overcurrent Timeout Programming Input. Connect a resistor between 500 and 500k from TIM to GND to program tFAULT. Leave TIM unconnected for a default timeout of 11ms. Power-On-Reset Programming Input. Connect a resistor between 500 and 500k 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. Ground 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 1F capacitor to GND. No Connection. Not internally connected. Slot B Present-Detect Input. PRES-DETB accepts inputs from PRSNT#_# on a PCIe connector. PRES-DETB has an internal 50k 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. Slot B Forced-On Input. FONB has a 50k 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. Slot A Present-Detect Input. PRES-DETA accepts inputs from PRSNT#_# on a PCIe connector. PRES-DETA has an internal 50k 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. Slot A Forced-On Input. FONA has a 50k 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. 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. 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. 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. 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. FUNCTION
23, 48, 49
3.3VAUXIN
24, 46 25
PGND TIM
26
PORADJ
27 28 29
GND 12VIN N.C.
30
PRES-DETB
31
FONB
32
PRES-DETA
33 34 35 36 37 38 39 40
FONA OUTPUT3 INPUT3 ONA AUXONA 12SA+ 12SA12GA
12
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Triple PCI Express, Hot-Plug Controllers
Pin Description (continued)
PIN 41 42 NAME 3.3SA+ 3.3SAFUNCTION 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. 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. 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. 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. 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. 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. 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.
MAX5957/MAX5958
43
3.3GA
44
FAULTA
45 47 50 51
PWRGDA 3.3AUXOA 3.3AUXOB PWRGDB
52
FAULTB
53
3.3GB
54 55 56
3.3SB3.3SB+ 12GB
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 0.2 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.
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Triple PCI Express, Hot-Plug Controllers MAX5957/MAX5958
RTIM TIM RPORADJ PORADJ IN OUT 12VIN PWRGD_ FAULT_
12S_+ + + -
108mV CHARGE PUMP
54mV 12S_5A 12G_
RSENSE
tFAULT DEBOUNCE
10A A01
tPOR OSCILLATOR
FAST OSCILLATOR 150A 120mA A001
MAX5957
3.3S_+ + + -
40mV
20mV 3.3S_5A 3.3G_
RSENSE
BIAS, REFERENCES, AND UVLO
10A
CONTROL LOGIC MAIN-CHANNEL
CONTROL LOGIC MAIN-CHANNEL 150A 150mA
CONTROL LOGIC AUX-CHANNEL + -
VREF CONTROL LOGIC AUX-CHANNEL UVLO
CHARGE PUMP
100A 3.3AUXO INPUT COMPARATOR AND CHIP CONTROL LOGIC
ON_
AUXON_
FON_
PRES-DET_
Figure 1. Single-Channel Internal Block Diagram
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Triple PCI Express, Hot-Plug Controllers
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 +150C. After an overcurrent or overtemperature fault condition, the MAX5957/MAX5958 latch off or automatically restart after a restart time delay. The power requirement for PCIe connectors is defined by the PCIe card specification and summarized in Table 1. * 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.
MAX5957/MAX5958
Startup
The main supply outputs can become active only after all the following events have occurred:
Table 1. Power Requirement for PCIe Connectors
POWER FAIL 3.3V Voltage Tolerance Supply Current Capacitive Load 12V Voltage Tolerance Supply Current Capacitive Load 3.3V AUXILIARY Voltage Tolerance Supply Current, Wake Enabled Supply Current, Nonwake Enabled Capacitive Load 9% (max) 375mA (max) 20mA (max) 150F (max) 9% (max) 375mA (max) 20mA (max) 150F (max) 9% (max) 375mA (max) 20mA (max) 150F (max) 8% (max) 0.5A (max) 300F (max) 8% (max) 0.5A (max) 1000F (max) 8% (max) 0.5A (max) 2000F (max) 9% (max) 3.0A (max) 1000F (max) 9% (max) 3.0A (max) 1000F (max) 9% (max) 3.0A (max) 1000F (max) X1 CONNECTOR X4/8 CONNECTOR X16 CONNECTOR
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Triple PCI Express, Hot-Plug Controllers MAX5957/MAX5958
Table 2. Control Logic Truth Table
ON_ X X Low High Low High AUXON_ X X Low Low High High FON_ Low High High High High High PRES-DET X High Low* Low* Low* Low* 12V_ AND 3.3V_ OUTPUTS On Off Off On Off On 3.3VAUXO_AUXILIARY OUTPUTS On Off Off Off On On
*PRES-DET_ high-to-low transition has a 4ms delay (tDEG).
ON_, AUXON_ VON_,TH VPGTH12 VPGTH3.3 12G_, 3.3G_ VON_,TH
ON_
12VO_, 3.3VO_
V12ILIM,TH RSENSE
12G_
12V OUTPUT CURRENT 3.3VAUXO_
VPGTH3.3AUX
3.3VAUXO_
PWRGD_
tPOR_HL PWRGD_ 3.3AUXIN RISING EDGE FAULT_
3.3VAUXIN RISING EDGE
2 x tFAULT FAULT_
PWRGD_ IS PULLED UP TO 3.3. FAULT_ IS PULLED UP TO 3.3AUXIN.
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 2. Power-Up Timing, No Fault
Figure 3. 12V Power-Up Timing (Turn-On into Output Overcurrent/Short Circuit)
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Triple PCI Express, Hot-Plug Controllers
fault on any of the channel's main outputs does not affect the auxiliary channel (V3.3AUXIN).
MAX5957/MAX5958
Power-Good (PWRGD_)
12G_ V12ILIM,TH RSENSE 12V OUTPUT CURRENT PWRGD_
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.
tFAULT
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.
When the die temperature goes above (TSD) +150C, 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).
Figure 4. 12 Output Overcurrent/Short Circuit During Normal Operation
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 (100s) 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.
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
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Triple PCI Express, Hot-Plug Controllers MAX5957/MAX5958
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.
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.
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 50k 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.
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.
INPUT tDBC DEBOUNCED OUTPUT tDBC tDBC
Figure 5. INPUT_ and OUTPUT_ Debounced Feature
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Triple PCI Express, Hot-Plug Controllers MAX5957/MAX5958
SHUT DOWN 12V AND 3.3V OUTPUTS. ASSERT FAULT_ STAY WAITING FOR tRESTART N FAULT STILL PRESENT? Y RESET tFAULT COUNTER
LATCH-OFF OPTION?
N
Y
N N ON_ TOGGLED HIGH LOW HIGH Y Y ARE ALL MAIN OUTPUTS OK? NO FAULT DETECTED
N
tFAULT ELAPSED?
START COUNTING tFAULT
Y
FAULT ON 12V OR 3.3V OUTPUTS N
Y
RESET FAULT_ ENABLE CHARGE ON 3.3G_ AND 12G_. START COUNTING tSU
Y
3.3VAUXIN IS OK, AUXON_ IS HIGH, PRES_DET IS LOW
MAIN INPUTS ARE OK, ON_ IS HIGH N
Y
tSU ELAPSED? N
N START PGOOD THRESHOLD MONITORING ALL PGOOD THRESHOLDS REACHED? ASSERT PWRGD_ AFTER tPOR_HL DELAY
ON_ AND AUXON_ TOGGLED HIGH LOW HIGH Y
N
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 SHUT DOWN ALL OUTPUTS. ASSERT FAULT_. STAY WAITING FOR tRESTART Y N
LATCH-OFF OPTION?
tFAULT ELAPSED?
START COUNTING tFAULT
FAULT ON 3.3AUXO_?
N
Y
FAULT STILL PRESENT?
Y
N
RESET tFAULT COUNTER
Figure 6. Fault Management Flowchart
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Triple PCI Express, Hot-Plug Controllers MAX5957/MAX5958
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 5A into the external gate capacitance to control the turn-on time of the external MOSFET. During turn-off, 12G_ sinks 150A 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 5A 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. tFAULT = (166ns / ) 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 = 5A. * 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 500 and 500k, respectively. Leave TIM floating for a default tFAULT of 10ms.
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 0.2. 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).
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 = (2.5s / ) x RPORADJ Maximum and minimum values for RPORADJ are 500 and 500k, 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.
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:
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Triple PCI Express, Hot-Plug Controllers MAX5957/MAX5958
Table 3. Component Manufacturers
COMPONENT Sense Resistor IRC Fairchild MOSFETs International Rectifier Motorola Vishay-Siliconix MANUFACTURER Vishay-Date PHONE 402-564-3131 704-264-8861 888-522-5372 310-322-3331 602-244-3576 -- WEBSITE www.vishay.com www.irctt.com www.fairchildsemi.com www.irf.com www.mot-sps.com/ppd www.vishay.com
Additional External Gate Capacitance
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.
Input Transients
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 4s (typ). Because some load fault conditions can cause voltage transients to propagate to the supply inputs with duration of greater than 4s, it is recommended that a small Schottky diode be placed in series with the 12VIN pin connection, upstream of the 1F 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
Triple PCI Express, Hot-Plug Controllers MAX5957/MAX5958
Typical Application Circuit
ONE OF THREE SLOTS SHOWN
V3.3VAUX PRSNT1# R1 8m +12V V12VMAIN
PCI EXPRESS SLOT_
0.1F
2.2F
IN5819 RPORADJ = OPEN RTIM = OPEN TIM
GND
12G_
12S_-
12S_+
3.3VAUXIN
12VIN
PORADJ
PWRGD 10k 3.3VAUX
PWRGD_
MAX5957 MAX5958
3.3VAUXO_ GND 3.3G_ 3.3S_V3.3VMAIN 0.1F R2 5m 3.3S_+ PRES-DET_ FAULT_ FON_ AUXON_ ON_ INPUT_ OUTPUT_
+3.3V ATTENTION SWITCH V3.3VAUXIN 10k PRSNT2#
MRL
MAX7313ATG 16-BIT I/O EXPANDER
2 2
LEDs
SMBus
AO-A2
INT
22
______________________________________________________________________________________
Triple PCI Express, Hot-Plug Controllers
Pin Configuration
TOP VIEW
PRES-DETA PRES-DETB OUTPUT3 AUXONA INPUT3 3.3SA+
MAX5957/MAX5958
3.3SA-
12SA+
12SA-
FONA
FONB
12GA
ONA
42 41 40 39 38 37 36 35 34 33 32 31 30 29 3.3GA 43 FAULTA 44 PWRGDA 45 PGND 46 3.3AUXOA 47 3.3AUXIN 48 3.3AUXIN 49 3.3AUXOB 50 PWRGDB 51 FAULTB 52 3.3GB 53 3.3SB- 54 3.3SB+ 55 12GB 56 1 12SB2 12SB+ 3 AUXONB 4 ONB 5 INPUT1 6 OUTPUT1 7 INPUT2 8 OUTPUT2 9 GND 10 11 12 13 14 PRES-DETC FONC AUXONC 12SC+ ONC 28 12VIN 27 GND 26 PORADJ 25 TIM 24 PGND 23 3.3VAUXIN 22 3.3AUXOC
MAX5957 MAX5958
N.C. 21 PWRGDC 20 FAULTC 19 3.3GC 18 3.3SC17 3.3SC+ 16 12GC 15 12SC-
+
THIN QFN
Chip Information
PROCESS: BiCMOS
______________________________________________________________________________________
23
Triple PCI Express, Hot-Plug Controllers MAX5957/MAX5958
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 E/2
DETAIL A
(NE-1) X e
k e D/2
D
(ND-1) X e
C L
D2
D2/2
b L E2/2 k
C L
E2
C L
C L
L e e
L
A1
A2
A
PACKAGE OUTLINE 32, 44, 48, 56L THIN QFN, 7x7x0.8mm
21-0144
F
1
2
24
______________________________________________________________________________________
32, 44, 48L QFN.EPS
Triple PCI Express, Hot-Plug Controllers
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.)
MAX5957/MAX5958
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
(c) 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.

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