MAX34440ETL+ Maxim Integrated Products, MAX34440ETL+ Datasheet - Page 27

• Manufacturer Part Number: MAX34440ETL+
• Description: Supervisory Circuits PMBUS 6-CH POW SUPPLY MANAGER
• Manufacturer: Maxim Integrated Products

Specifications of MAX34440ETL+

• Minimum Operating Temperature: - 40 C
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.7 V
• Supply Current (typ): 2.5 mA
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 85 C
• Package / Case: TQFN-40
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The VOUT_MARGIN_LOW command loads the device with the voltage to which the power-supply output is to be
changed when the OPERATION command is set to margin low. If the power supply is already operating at margin low,
changing VOUT_MARGIN_LOW has no effect on the output voltage. The device only adjusts the power supply to the
new VOUT_MARGIN_LOW voltage after receiving a new margin low OPERATION command. The 2 data bytes are in
DIRECT format. If the device cannot successfully close-loop margin the power supply, the device keeps attempting to
margin the supply and does the following:
1) Sets the NONE OF THE ABOVE bit in STATUS_BYTE.
2) Sets the NONE OF THE ABOVE and MFR bits in STATUS_WORD.
3) Sets the MARGIN_FAULT bit in STATUS_MFR_SPECIFIC.
4) Notifies the host through ALERT assertion (if enabled in MFR_MODE).
VOUT_SCALE_MONITOR is used in applications where the measured power-supply voltage is not equal to the voltage
at the ADC input. For example, if the ADC input expects a 1.0V input for a 12V output, VOUT_SCALE_MONITOR =
1.0V/12V = 0.0833. In applications where the power-supply output voltage is greater than the device input range, the
output voltage of the power supply is sensed through a resistive voltage-divider. The resistive voltage-divider reduces
or scales the output voltage. The PMBus commands specify the actual power-supply output voltages and not the input
voltage to the ADC. To allow the device to map between the power-supply voltage (such as 12V) and the voltage at
the ADC input, the VOUT_SCALE_MONITOR command is used. The 2 data bytes are in DIRECT format. This value is
dimensionless. For example, if the required scaling factor is 0.0833, then VOUT_SCALE_MONITOR should be set to
0AABh (2731/32,767 = 0.0833).
Table 13. VOUT_SCALE_MONITOR
Note: On the device, the full-scale ADC voltage is 1.225V. A scaling factor where a 1.0V ADC input represents a nominal 100%
voltage level is recommended.
The IOUT_CAL_GAIN command is used to set the ratio of the voltage at the ADC input to the sensed current. The units
of the IOUT_CAL_GAIN factor are 0.1mI. The 2 data bytes are in DIRECT format. For example, if a 10mI sense resis-
tor is used with a 50V/V current-sense amplifier, the IOUT_CAL_GAIN should be set to 500mI or 1388h.
USER NOTE: On the device, the full-scale ADC voltage is 1.225V. The value of the sense resistor and current-
sense amplifier gain must be scaled appropriately.
NOMINAL VOLTAGE LEVEL
MONITORED (V)
1.2
1.5
1.8
2.5
3.3
12
5
PMBus 6-Channel Power-Supply Manager
NOMINAL ADC INPUT VOLTAGE
LEVEL (V) (SEE NOTE)
1.0
1.0
1.0
1.0
1.0
1.0
1.0
RESISTIVE VOLTAGE-
DIVIDER RATIO
0.0833
0.833
0.667
0.555
0.303
0.4
0.2
VOUT_SCALE_MONITOR (2Ah)
VOUT_MARGIN_LOW (26h)
IOUT_CAL_GAIN (38h)
VOUT_SCALE_MONITOR
VALUE (HEX)
6AAAh
0AABh
470Ah
26C8h
5555h
3333h
1999h
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