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The MAX6876 EEPROM-configurable, multivoltage
power tracker/supervisor monitors four system voltages
and ensures proper power-up and power-down conditions
for systems requiring voltage tracking and/or
sequencing. The MAX6876 provides a highly configurable
solution as key thresholds and timing parameters
are programmed through an I²C interface and
these values are stored in internal EEPROM. The
MAX6876 also provides supervisory functions and an
overcurrent detection circuit.
The MAX6876 features programmable undervoltage and
overvoltage thresholds for each input supply. When all
voltages are within specifications, the device turns on the
external n-channel MOSFETs to either sequence or track
the voltages to the system. All of the voltages can be
sequenced or tracked or powered up with a combination
of the two options. During tracking, the voltage at the
GATE of each MOSFET is increased to slowly turn on
each supply. The voltages at the source of each MOSFET
are compared to each other to ensure that the voltage differential
between each monitored supply does not
exceed 250mV (typ). Tracking is dynamically adjusted to
force all outputs to track within a ±125mV window from a
reference ramp; if, for any reason, any supply fails to
track within ±250mV from the reference ramp, a FAULT-bar
output is asserted, the power-up mode is terminated, and
all outputs are powered off. Power-up mode is also terminated
if the controlled voltages fail to complete the rampup
within a programmable FAULT-bar timeout. The MAX6876
features latch-off and autoretry modes to power on again
after a fault condition has been detected.
Other features of the MAX6876 include a reset circuit, a
manual reset input (MR-bar), and a margin disable input
(MARGIN-bar). The device also features outputs for indicating
a power-good condition (PG_) and an overcurrent
condition (OC-bar), and a bus-removal (REM) output.
The MAX6876 is available in a small 6mm x 6mm, 36-pin thin QFN package and is fully specified over the
extended -40°C to +85°C temperature range.
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