MAX34441EVKIT# Maxim Integrated, MAX34441EVKIT# Datasheet - Page 22

• Manufacturer Part Number: MAX34441EVKIT#
• Description: Power Management IC Development Tools MAX34441 Eval Kit
• Manufacturer: Maxim Integrated
• Type: PWM Controllersr
• Series: MAX34441r

Specifications of MAX34441EVKIT#

• Rohs: yes
• Product: Power Management Development Tools
• Tool Is For Evaluation Of: MAX34441
• Interface Type: I2C
• Maximum Operating Temperature: + 85 C
• Part # Aliases: 90-34441#K00

PMBus 5-Channel Power-Supply Manager
and Intelligent Fan Controller
particular fault. Table 5 illustrates the required con-
ditions and fault actions for specific parameters.
The device uses an internal watchdog timer that is inter-
nally reset every 5ms. In the event that the device is
locked up and this watchdog reset does not occur after
500ms, the device automatically resets. After the reset
occurs, the device reloads all configuration values that
were stored to flash and begins normal operation. After
the reset, the device also 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
3) Sets the WATCHDOG bit in STATUS_MFR_SPECIFIC.
4) Notifies the host through ALERT assertion (if enabled
The device can monitor up to six different temperature
sensors. It can monitor up to four remote I
perature sensors plus a remote diode and its own internal
temperature sensor. Each of the enabled temperature
sensors is measured once a second. The remote diode
and internal temperature sensors are averaged four
times to reduce the affect of noise. Each time the device
attempts to read a temperature sensor it checks for
faults. For the remote diode, a fault is defined as reading
greater than +160NC or less than -60NC. For the internal
temperature sensor, a fault is defined as reading greater
than +130NC or less than -60NC. For the I
sensors, a fault is defined as a communication access
failure. Temperature sensor faults are reported by set-
ting the temperature reading to 7FFFh. A temperature
sensor fault results in the setting of the TEMPERATURE
bit in STATUS_BYTE and STATUS_WORD and ALERT is
asserted (if enabled in MFR_MODE). No bits are set in
STATUS_MFR_SPECIFIC.
The temperatures do not have to be used to control the
fan speed. They can be enabled and used for tempera-
ture monitoring only. Reading disabled temperature sen-
sors returns a fixed value of 0000h.
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.
The device can control up to four DS75LV digital temper-
ature sensors. The A0, A1, and A2 pins on the DS75LV
22
STATUS_WORD.
in MFR_MODE).
Temperature Sensor Operation
System Watchdog Timer
2
2
C temperature
C-based tem-
should be configured as shown in Table 6. The thermo-
stat function on the DS75LV is not used and thus the O.S.
output should be left open circuit.
Fan control has four operational modes. The mode is
determined by the combination of FAN_COMMAND_1
and bit 6 of FAN_CONFIG_1_2 (see Table 7). Fan control
can be disabled by setting bit 7 in FAN_CONFIG_1_2 to
zero.
In dual fan applications operating in RPM mode, the
tachometer selected when TACHSEL = 0 is close-
loop-controlled to the target RPM. Once PWM ramp-
ing is complete, TACHSEL toggles between the two
tachometers every 500ms for monitoring purposes. The
slower of the two tachometer signals is reported by
READ_FAN_SPEED_1 and is used as a comparison for
fan faults and warning. In dual fan applications operating
in PWM mode, TACHSEL always switches every 500ms.
If one of the two tachometer signals operate at a slower
speed, it is recommended that the slower tachometer be
presented to the TACH input when TACHSEL = 0.
In the automatic mode, the fan is controlled in a closed
loop based on the controlling temperature (the highest
postnormalized temperature reading) and the associ-
ated fan control PWM duty cycle (in %) or fan speed
(in RPM). These parameters are assigned in the fan
lookup table (LUT). See the MFR_FAN_LUT description
for configuration details. When a controlling temperature
exceeds the temperature level programmed in the LUT,
the device outputs a PWM duty cycle or adjusts the fan
speed, associated with that temperature. See Figure 1
for an example.
Table_6._DS75LV_Address_Pin_
Configurations
PAGE
10
7
8
9
TEMP SENSOR I
TEMP SENSOR I
TEMP SENSOR I
TEMP SENSOR I
TEMP_SENSOR
MAX34441_I
Automatic Fan Control Operation
Fan Control Operation
2
C_
2
2
2
2
C 0
C 1
C 2
C 3
Dual Fan Applications
DS75LV_ADDRESS_PIN_
A2
0
0
0
0
CONFIGURATION
A1
0
0
1
1
A0
0
1
0
1