MIC2341 MICREL [Micrel Semiconductor], MIC2341 Datasheet - Page 23

• Manufacturer Part Number: MIC2341
• Description: Dual-Slot PCI Express Hot-Plug Controller
• Manufacturer: MICREL [Micrel Semiconductor]

Thermal Shutdown
The internal VAUX[A/B] MOSFETs are protected against
damage
overtemperature
overcurrent condition on either VAUX[A] or VAUX[B]
raise the junction temperature of the MIC2341 to 140°C,
all of the outputs for that corresponding slot (including
VAUX) will be shut off and that slot’s /FAULT_AUX
output will be asserted. The slot’s /FAULT_MAIN output
will not be asserted. The other slot’s operating condition
will remain unaffected. However, should the MIC2341’s
die
overcurrent fault condition on both VAUX[A] and
VAUX[B], both slots (all outputs, including VAUXA and
VAUXB)
/FAULT_AUX[A/B] output signals will be asserted; the
/FAULT_MAIN[A/B] output signals will not be asserted.
Plug-in Card Retention Switch Inputs
Two pins on the MIC2341 are available for use as card
retention switch inputs, /CRSW[A/B]. These pins are
internally pulled-up by 45kΩ resistors to VSTBY and
prevent the enabling of all gate drive circuits on
12GATE[A/B], 3VGATE[A/B], and VAUX[A/B] unless
these input pins are asserted LOW. In addition, each of
these inputs exhibits an internal debounce delay time of
approximately 10ms.
Micrel, Inc.
October 2007
temperature
not
will
be
only
protection
exceed
shut
Figure 7. MIC2341R Auto-Retry Timing Diagram and Operation in Current-limit
by
off.
current
160°C
as
In
well.
limiting,
this
because
Should
case,
but
of
both
an
an
by
23
/FORCE_ON[A/B] Inputs
These level sensitive, asserted active-low digital inputs
are internally pulled up to VSTBY through a weak
current source and are intended for diagnostics during
the debug phase of the system design involving the
MIC2341. In asserting /FORCE_ON[A/B] LOW, all three
of the respective slot’s outputs (+12V, +3.3V, and VAUX)
will turn on. However, all protections for those outputs
are disabled. This explicitly includes all overcurrent and
short circuit protections, and on-chip thermal protection
for the VAUX supplies. Additionally, asserting a slot’s
/FORCE_ON[A/B] input will disable all of its input and
output UVLO protections, with the sole exception of that
asserting either or both of the /FORCE_ON[A/B] inputs
will not disable the VSTBY[A/B] input UVLO.
Asserting
respective slot’s /PWRGD[A/B], and /DLY_PWRGD[A/B]
output
/FAULT_MAIN[A/B], the /FAULT_AUX[A/B},
and the SYSPWRGD output signals to enter their open-
drain state.
/PWRGD[A/B] and /DLY_PWRGD Digital Outputs
The MIC2341 has two /PWRGD outputs and two
/DLY_PWRGD outputs, one for each slot. These are
open-drain, active-low outputs that are activated after
power-on-reset and are normally connected by an
signals
/FORCE_ON[A/B]
to
be
asserted
LOW
LOW
MIC2341/2341R
will
M9999-102507-A
[phone]
cause
while
the /INT,
the
the