SMT4214 Summit Microelectronics, Inc., SMT4214 Datasheet - Page 2

• Manufacturer Part Number: SMT4214
• Description: Expandable Four-rail Supply TRAKKER™ Controller
• Manufacturer: Summit Microelectronics, Inc.

GENERAL DESCRIPTION
manager designed for use on a distributed power or
multi-supply rail circuit card.
resident on the circuit card in the form of LDO’s or DC-
to-DC converters or the supplied voltages can be
present on the backplane of the system.
configuration, the SMT4214 will monitor both the raw
voltages at their source and also on the circuit side of
the power MOSFETs it is controlling.
control. The device can be programmed to turn on the
MOSFET’s with a controlled MOSFET gate slew rate
in a soft start mode.
programmed so that the MOSFETs are turned on so
that the voltages being applied to the circuitry are
‘tracked.’
manager on the SMT4214. If there are more than four
supplies, the SMT4214 can be linked with other
SMT4214’s through the use of the PWR_ON#, LINK#,
VRLINK and FS# pins.
monitor their respective voltage supplies. The under-
voltage
increments to monitor voltages within the range of
0.9V to 6.0V.
programmed to assert IRQ#, RST# or FS#.
DETAILED DEVICE OPERATION
SUPPLY MANAGERS
the associated MOSFET’s, on a printed circuit card
effectively divides the board into two electrical
domains; the bus-side and the card-side. The bus-side
constitutes the power supply sources either from the
backplane or on-board LDOs or DC-to-DC converters.
The card-side is comprised of the components that are
powered by the voltage sources on the output side of
the MOSFET’s.
each comprised of a programmable bus-side voltage
threshold comparator and a secondary comparator for
monitoring card-side voltages and programmable logic
to determine device reactions to changes in the
detected thresholds.
individual managers. The curved resistive element is
a symbolic representation of a non-volatile DAC.
When using the SMX3200 (dongle) and GUI software
the selected threshold level is programmed into the
Summit Microelectronics, Inc
The SMT4214 is a fully integrated power supply
A key function of the SMT4214 is the MOSFET
Each supply on the card is assigned its own
The individual managers are programmed to
The electrical placement of the SMT4214, and
The SMT4214 has four identical supply managers
Figure 1 illustrates the functional segments of the
threshold
Under-voltage conditions can be
is
programmable
Alternatively it can be
The supplies can be
in
In either
20mV
2061 1.0 8/16/02
SMT4214, effectively adjusting the output of the DAC
to the requested threshold detection level.
different voltage potentials for each supply are
measured, the pre-MOSFET threshold VI (bus-side
voltage) and the post-MOSFET threshold VO (card-
side voltage). The VI threshold is set by a non-volatile
DAC. The VO threshold is set to 200mV below the VI
threshold.
or VO dropping below its programmed threshold. A
programmable under-voltage filter requires that, after
the soft start and tracking are complete, an under-
voltage condition must remain for a filter interval,
t
SOFT START
will ramp at a constant slew rate of 500V/s until it
reaches its maximum value. This type of operation
would commonly be used where a bus voltage ( e.g.,
5V) is first switched to a DC-to-DC converter or group
of LDOs; and then their outputs would be switched in a
tracking mode to the card-side logic.
start mode.
should be set to minimum, and the VO and VI inputs
should be tied to VDD_CAP.
TRACKING
least two channels are programmed to track.
However, a single channel can be set to track and is
compared against an internally set tracking model.
During tracking, the card-side voltages are monitored
to minimize the differential voltage between any of
these voltages until they reach their respective
thresholds.
inherently adaptive with a maximum of 500V/s. That
is, if there is any difference between the VO inputs in
the linear region, the VGATE outputs are adjusted to
minimize the differential.
FILTER
V O
V I
An under-voltage condition is defined as either VI
If a channel is set to soft start, its VGATE output
All unused channels must be programmed to soft-
The tracking operation normally requires that at
In the tracking mode, the ramp rates are
, before any action is taken.
Figure 1. Supply Manager
The thresholds for unused channels
Offset
V
R E F
Preliminary Information
+
+
-
-
SMT4214
Two
UV
2