ADT7473ARQZ-RL7 ON Semiconductor, ADT7473ARQZ-RL7 Datasheet - Page 36

• Manufacturer Part Number: ADT7473ARQZ-RL7
• Description: IC REMOTE THERMAL CTLR 16QSOP
• Manufacturer: ON Semiconductor
• Series: dBCool®r

Specifications of ADT7473ARQZ-RL7

• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, Fan Speed Counter, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, External Sensor
• Output Type: SMBus™
• Output Alarm: No
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Full Temp Accuracy: +/- 0.5 C
• Digital Output - Bus Interface: Serial (3-Wire, 4-Wire)
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Step 4: PWM
fan in the system runs. It is also the start speed for each fan
under automatic fan control once the temperature rises
above T
benefit, PWM
Depending on the fan used, the PWM
in the 20% to 33% duty cycle range. This value can be found
through fan validation.
PWM
Figure 53. PWM
MIN
PWM
MIN
100%
MIN
0%
(see Figure 53). For maximum system acoustic
is the minimum PWM duty cycle at which each
MIN
MIN
for Each PWM (Fan) Output
PWM Duty Cycle
should be set as low as possible.
T
MIN
MIN
Determines Minimum
TEMPERATURE
Figure 52. Understanding the T
MIN
setting is usually
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single temperature measurement channel. For example,
Remote 1 temperature can control PWM1 and PWM2
outputs. If two different fans are used on PWM1 and PWM2,
the fan characteristics can be set up differently. As a result,
Fan 1 driven by PWM1 can have a different PWM
than that of Fan 2 connected to PWM2. Figure 54 illustrates
this as PWM1
cycle of 20%, while PWM2
minimum of 40% duty cycle. However, both fans turn on at
exactly the same temperature, defined by T
More than one PWM output can be controlled from a
MIN
Parameter
MIN
(front fan) is turned on at a minimum duty
MIN
(rear fan) turns on at a
MIN
.
MIN
value