max5957letnt Maxim Integrated Products, Inc., max5957letnt Datasheet - Page 15

• Manufacturer Part Number: max5957letnt
• Description: Triple Pci Express, Hot-plug Controllers
• Manufacturer: Maxim Integrated Products, Inc.

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 com-
mand, the MAX5957/MAX5958 enhance the external
and internal MOSFETs slowly with a constant gate cur-
rent to limit the power-supply inrush current. The
MAX5957/MAX5958 actively limit the current of all out-
puts 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 cir-
cuitry also shuts down all outputs if the die temperature
exceeds +150°C. After an overcurrent or overtempera-
ture 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.
The main supply outputs can become active only after
all the following events have occurred:
Table 1. Power Requirement for PCIe Connectors
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
POWER FAIL
______________________________________________________________________________________
Triple PCI Express, Hot-Plug Controllers
X1 CONNECTOR
1000µF (max)
375mA (max)
300µF (max)
150µF (max)
20mA (max)
±9% (max)
3.0A (max)
±8% (max)
0.5A (max)
±9% (max)
Startup
• V
• V
• 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:
• V
• 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 sum-
marizes the logic conditions required for startup. The aux-
iliary supply input powers the internal control logic and
analog references of the MAX5957/MAX5958, so the main
supplies cannot be enabled, if V
When an output is enabled, a programmable startup
timer (t
The value of t
(t
sets the duration of t
FAULT
threshold.
3.3AUXIN
12VIN
3.3AUXIN
SU
). R
X4/8 CONNECTOR
) begins to count the startup time duration.
and V
1000µF (max)
1000µF (max)
375mA (max)
TIM
150µF (max)
20mA (max)
±9% (max)
3.0A (max)
±8% (max)
0.5A (max)
±9% (max)
is above its UVLO threshold.
is above its UVLO threshold.
SU
externally connected from TIM to GND
3.3SA+
is set to 2x the fault timeout period
FAULT
are both above their UVLO
.
3.3VAUXIN
X16 CONNECTOR
1000µF (max)
2000µF (max)
375mA (max)
150µF (max)
20mA (max)
±9% (max)
3.0A (max)
±8% (max)
0.5A (max)
±9% (max)
is not present.
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