MAX5957 MAXIM [Maxim Integrated Products], MAX5957 Datasheet - Page 17

• Manufacturer Part Number: MAX5957
• Description: Triple PCI Express, Hot-Plug Controllers
• Manufacturer: MAXIM [Maxim Integrated Products]

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
asserts and the controller disengages both the 12V and
3.3V outputs for the particular slot (see the Fault
Management section).
The auxiliary output current is internally monitored and
actively limited to the maximum current-limit value. An
overcurrent fault condition occurs when the output cur-
rent exceeds the overcurrent threshold for longer than
t
plies of the affected channel to be disabled after a pro-
grammable time period t
A fault condition on a main channel (V
causes all the channel’s main outputs to shut down
after the t
matically restart after the t
t
Figure 4. 12 Output Overcurrent/Short Circuit During Normal
Operation
FAULT
FAUALT
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.
12V and 3.3V Outputs Normal Operation
3.3V Auxiliary Output Normal Operation
V
12ILIM,TH
. A fault on an auxiliary channel causes all sup-
R
) period, depending on the device version. A
SENSE
FAULT
period and then either latch off or auto-
______________________________________________________________________________________
Triple PCI Express, Hot-Plug Controllers
FAULT
t
FAULT
RESTART
.
(t
12VIN
RESTART
FAULT
or V
FAULT_
12G_
12V OUTPUT
CURRENT
PWRGD_
, FAULT_
= 64 x
3.3VIN
)
fault on any of the channel’s main outputs does not
affect the auxiliary channel (V
Power-good (PWRGD_) is an open-drain output that
pulls low a time (t
respective slot are fully on. All outputs are considered
fully on when 3.3G_ has risen to V
risen to V
V
by connecting a resistor from PORADJ to GND. See the
Setting the Power-On Reset and Timeout Period
(t
pletely skip the POR time delay for PWRGD_ assertion.
When the die temperature goes above (T
overtemperature fault occurs and the MAX5957/
MAX5958 shut down all outputs. The devices wait for the
junction temperature to decrease below T
before entering fault management (see the Fault
Management section).
A fault occurs when an overcurrent or 12G_ or 3.3G_
below the power-good threshold lasts longer than
t
ature condition:
• A fault on a main output (12V or 3.3V) shuts down
• A fault on the 3.3V auxiliary output shuts down all
The MAX5957A/MAX5958A automatically restart from a
fault shutdown after the t
MAX5957L/MAX5958L latch off. If an overcurrent fault
occurred on a main output, bring ON_ low for at least
t
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 mini-
mum of t
AUXON_ to reset the fault condition. If ON_ and
AUXON are toggled before t
elapsed, the MAX5957L/MAX5958L store the informa-
tion and restart when the delay is finished. The
MAX5957A/MAX5958A (autoretry versions) restart all
channels automatically after t
FAULT
RESET
PGTH3.3AUX
POR_HL
both main outputs of the respective slot. The 3.3V
auxiliary is not affected.
three outputs of the respective slot.
or when the device experiences an overtemper-
(100µs) and high again to reset the fault and
) sections. Connect PORADJ to GND to com-
RESET
PGTH12
. t
POR_HL
to reset the fault. Toggle ON_ or only
POR_HL
, and V
is adjustable from 2.4ms to 1.5s
Power-Good (PWRGD_)
) after all the outputs of the
RESTART
RESTART
RESTART
3.3AUXIN
3.3AUXO_
Thermal Shutdown
Fault Management
PGTH3.3
.
time counting has
).
period while the
SD
is less than
SD
) +150°C, an
, 12G_ has
- hysteresis
17