MAX34441ETL+ Maxim Integrated Products, MAX34441ETL+ Datasheet - Page 25

• Manufacturer Part Number: MAX34441ETL+
• Description: Supervisory Circuits PMBUS 5-CH POW-SUPPLY MANAGER & INTELLIGENT FAN CONTLR
• Manufacturer: Maxim Integrated Products

Specifications of MAX34441ETL+

• Internal Hysteresis: Yes
• Operating Temperature Range: - 40 C to + 85 C
• Output Type: Push-Pull
• Number Of Voltages Monitored: 5
• Watchdog: Yes
• Supply Voltage (max): 3.3 V
• Supply Current (typ): 8 A
• Maximum Power Dissipation: 2857.1 mW
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 85 C
• Package / Case: TQFN-40
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 3 shows the fan spin-up process. When the fan is
spinning up, the number of revolutions is checked every
200ms for up to 2s. When the number of cumulated revo-
lutions is greater than or equal to the spin-up relaxation
criteria, the fan passes spin-up. If the fan has a locked
rotor output, fan spin-up passes when the locked rotor
signal is no longer asserted.
Figure 3. Fan Spin-Up
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0
PMBus 5-Channel Power-Supply Manager
AUTOMATIC
SPIN-UP
ENABLED
AUTOMATIC
SPIN-UP
DISABLED
0.2
0.4
Fan Spin-Up
SPIN-UP
CRITERIA MET
and Intelligent Fan Controller
0.6
CYCLE AFTER AUTOMATIC SPIN-UP
ALWAYS RETURN TO 40% DUTY
BEFORE BEGINNING PWM RAMP
(EVEN IF BEYOND 1 SECOND)
TIME (SECONDS)
When spin-up passes, the device forces the fan PWM
with a 40% duty cycle. The 40% duty cycle is maintained
until the next temperature conversion is completed,
which occurs once a second. After the temperature con-
version, the device enters either manual mode operation
or automatic operation using MFR_FAN_LUT.
0.8
1.0
RAMP PWM TO TARGET PWM OR RPM
(CONSTRAINED BY THE RAMP BITS)
INITIAL TARGET PWM OR
RPM DETERMINED AFTER
TEMPERATURE CONVERSION
1.2
1.4
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