MAX34441EVKIT# Maxim Integrated, MAX34441EVKIT# Datasheet - Page 47

• 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

Table_32._MFR_FAN_CONFIG_(continued)
Note: It is recommended that the fan be disabled prior to changing MFR_FAN_CONFIG.
BIT
7:5
1:0
4
3
2
ROTOR_HI_LO
BIT_NAME
RAMP[2:0]
SPIN[1:0]
ROTOR
PMBus 5-Channel Power-Supply Manager
0
The RAMP bits select how fast the device ramps the PWM from one duty cycle to another (either up
or down). In PWM mode, the following table always applies. In RPM mode, the fan speed is read
either every 200ms or 1000ms and when the reported fan speed is within 20% of the target speed,
the maximum allowed PWM duty cycle change is set to 1%. In RPM mode, the PWM duty cycle is
not changed as long as the fan is within Q5% of the target speed.
Determines if a locked rotor indication is active low or active high. This bit is ignored if
ROTOR = 0.
0 = ROTOR is active low (TACH input is low if the rotor stops).
1 = ROTOR is active high (TACH input is high if the rotor stops).
The ROTOR bit selects if the fan does not have a tachometer but rather a stalled (or locked)
rotor output.
The SPIN bits determine how the device spins up (or starts) the fan from a dead stop. To over-
come the initial mechanical fan inertia, the device can be programmed to drive the fan at 100%
duty cycle until a programmable number of fan revolutions (cumulative count) is detected or a
locked rotor signal is negated. The device allows a 2s startup period during which the fan speed
monitors are disabled. If after 2s the fan does not respond, the PWM output remains at 100%
duty cycle (if TACHO = 0) or goes to 0% duty cycle (if TACHO = 1).
This bit always returns a 0.
RAMP2
ROTOR
SPIN1
0
0
0
0
1
1
1
1
0
1
0
0
1
1
RAMP1
and Intelligent Fan Controller
Stalled/locked rotor
0
0
1
1
0
0
1
1
FAN_OUTPUT
Tachometer
detect
SPIN0
RAMP0
0
1
0
1
0
1
0
1
0
1
0
1
CYCLE_UPDATE_
TACH input expects fan RPM
TACH input expects locked rotor signal. The polarity is
selected with the ROTOR_HI_LO bit (also set
MFR_FAN_FAULT_LIMIT = 0001h).
Automatic spin-up disabled
Two revolutions or locked rotor negated
Four revolutions or locked rotor negated
Eight revolutions or locked rotor negated
PWM_DUTY_
RATE_(ms)
MEANING
1000
1000
1000
200
200
200
200
200
SPIN-UP_RELAXATION_CRITERIA
MAX34441_CONFIGURATION
MAX_PWM_DUTY_
CYCLE_CHANGE_
ALLOWED_(%)
1
2
3
1
2
3
4
5
100%_PWM_DUTY_
CYCLE_(seconds)
TIME_TO_RAMP_
FROM_40%_TO_
2.4
60
30
20
12
6
4
3
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