SMH4044 Datasheet, PDF (6/20 Pages) Summit Microelectronics, Inc. – Compact PCI Hot-Swap Controller With IPMI Support

SMH4044
Preliminary
CBI_5 (44)
CBI_5 is the circuit breaker input for the supply voltage.
With a series resistor placed in the supply path between
the 5V early power and CBI_5, the circuit breaker will trip
whenever the voltage across the resistor exceeds 50mV.
HST_3V_MON (35)
This input monitors the host 3.3V supply and it is used as
a reference for the circuit breaker comparator. If VCC3
falls below VTRIP then SGNL_VLD# is de-asserted, the
high side drivers are disabled, and LOCAL_PCI_RST# is
asserted.
ISLEW (46)
A Diode-connected NFET input. It may be used to adjust
the 250V/s default slew rate of the high-side driver
outputs.
PCI_RST# (21)
A TTL level reset input signal from the host interface. A
high to low transition (held low longer than 40ns) will
initiate a reset sequence. The LOCAL_PCI_RST# and
LOCAL_PCI_RST outputs will be driven active for a
minimum period of tPURST. If the PCI_RST# input is still
held low after tPURST times out the reset outputs will
continue to be driven until PCI_RST# is released.
PWR_EN (4)
A TTL level input that allows the host to enable or disable
the power to the individual card. During initial power up
this signal would start in a low state, and then be driven
high during software initialization. If this signal is driven
low then the power supply control outputs will be driven
into the inactive state and the reset signals asserted. In
a non-High Availability system this input can be tied high.
The PWR_EN input is also used to reset the SMH4044
circuit breakers. After an over-current condition is
detected the VGATE outputs can be turned back on by
first taking PWR_EN low then returning it high.
VSEL (3)
A TTL level input used to determine which of the host
power supply inputs will be monitored for valid voltage and
reset generation. This is a static input and the pin should
be tied to VCC or ground through a resistor. VSEL is high
for 3.3V power, and low for 5V or mixed mode power.
VCC (42)
The power supply input. It is monitored for power integrity.
If it falls below the 5V sense threshold (VTRIP) and the
VSEL input is low then the SGNL_VLD# and HEALTHY#
signals are de-asserted, the high side drivers disabled,
and reset outputs asserted. On a CompactPCI board this
must be connected to early power.
GND (18)
Power supply return line. Ground should be applied at the
same time as early power.
BD_SEL1#, BD_SEL2# (16, 15)
These are active low TTL level inputs with internal pull-
ups to VCC. When pulled low they indicate full board
insertion. On the host side the signals should be directly
tied to ground. In a High Availability application these
inputs can be the last pins to mate with the backplane.
Alternatively, they can be actively driven by the host, or
be connected to switches interfaced to the board ejectors,
or any combination. Both inputs must be low before the
SMH4044 will begin to turn on the card side voltage.
DRVREN# (45)
An open-drain, active-low output that indicates the status
of the 3V and 5V high side driver outputs (VGATE5 and
VGATE3). This signal may also be used as a switching
signal for the 12V supply.
FAULT# (1)
An open-drain, active-low output. It will be driven low
whenever an over-current condition is detected. It will be
reset when the PWR_EN signal is brought low.
HEALTHY# (19)
An open-drain, active-low output indicating card side
power inputs are above their reset trip levels.
LOCAL_PCI_RST# (8)
An open-drain active-low output. It is used to reset the
card side circuitry on the add-in card. It is active
whenever the card-side monitor inputs are below their
respective VTRIP levels. It may also be driven low by a low
input on the PCI_RST# pin.
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2057 1.x 8/16/01
SUMMIT MICROELECTRONICS, Inc.