Datasheet

MAX34446
PMBus Power-Supply Data Logger
15Maxim Integrated
Voltage/Current Monitoring
ADC inputs 0 to 3 can be independently configured to
monitor either voltage or current. The device defaults to
monitoring voltage on the ADC0 to ADC3 inputs, but if the
IOUT_OC_FAULT_LIMIT command is configured with a
positive nonzero value, the device instead monitors cur-
rent on the associated ADC input. When an ADC input
is configured to monitor voltage, all current related com-
mands (like READ_IOUT) are invalid on the associated
page and, likewise when an ADC input is configured to
monitor current, all voltage-related commands are invalid
and the PGn outputs are forced high impedance.
Power Calculation
The device can be configured to calculate power con-
sumption. The READ_POUT, MFR_POUT_PEAK, and
MFR_POUT_AVG commands only contain valid data
when the device is configured as shown below. The
device can calculate power on up to two power nodes
by using 4 channels of the ADC: two for voltage mea-
surement and two for current measurement. To measure
power, ADC0 and ADC1 must be coupled together and
ADC2 and ADC3 must be coupled together. Since the
PMBus page alignment is assigned based on the ADC
input, power is reported in both pages of the associated
coupled voltage/current pair.
Temperature Sensor Operation
The device can monitor up to three different temperature
sensors, two external remote diode temperature sensors
plus its own internal temperature sensor. The device
defaults to having the temperature sensors disabled,
but if the OT_FAULT_LIMIT command is configured
with a positive nonzero value, the temperature sensor is
enabled on the associated page. The device reads one
of the enabled temperature sensors once per second.
Hence, if only one temperature sensor is enabled, it is
read every second. If all three temperature sensors are
enabled, each sensor is read once every 3 seconds.
Each time the device attempts to read a temperature
sensor, it checks for faults. For the remote diode, a fault
is defined as a reading greater than +160NC or less than
-60NC. For the internal temperature sensor, a fault is
defined as a reading greater than +130NC or less than
-60NC. Temperature sensor faults are reported by setting
the temperature reading to 7FFFh. A temperature sensor
fault results in the setting of the TEMPERATURE bit in
STATUS_BYTE and STATUS_WORD. No bits are set in
STATUS_MFR_SPECIFIC.
The remote diode temperature sensor can support either
npn or pnp transistors. The device automatically cancels
the series resistance that can affect remote diodes that
are located far from the device.
Power Measurement 1
(Page 0 or 1)
ADC0 = Voltage
Measurement (Page 0)
ADC1 = Current
Measurement (Page 1)
Power Measurement 2
(Page 2 or 3)
ADC2 = Voltage
Measurement (Page 2)
ADC3 = Current
Measurement (Page 3)