ADT7473ARQZ-1RL ON Semiconductor, ADT7473ARQZ-1RL Datasheet - Page 42

• Manufacturer Part Number: ADT7473ARQZ-1RL
• Description: IC REMOTE THERMAL CTLR 16QSOP
• Manufacturer: ON Semiconductor
• Series: dBCool®r

Specifications of ADT7473ARQZ-1RL

• 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

hysteresis for fan on/off, but the same setting is used for the
T
Temperature Channels section. Therefore, programming
Register 0x6D and Register 0x6E sets the hysteresis for both
fan on/off and the THERM function.
Hysteresis Registers
Register 0x6D, Remote 1, Local Hysteresis Register
Bits [7:4], Remote 1 temperature hysteresis (4°C default)
Enhanced Acoustics Register 1 (0x62)
Bit 7 (MIN3) = 0, PWM3 is off (0% PWM duty cycle) when
temperature is below T
Bit 7 (MIN3) = 1, PWM3 runs at PWM3 minimum duty
cycle below T
Bit 6 (MIN2) = 0, PWM2 is off (0% PWM duty cycle) when
temperature is below T
Bit 6 (MIN2) = 1, PWM2 runs at PWM2 minimum duty
cycle below T
THERM
The T
HYST
hysteresis value, described in Step 6: T
MIN
MIN
setting applies not only to the temperature
Figure 63. The T
− T
− T
HYST
HYST
MIN
MIN
.
.
− T
− T
HYST
HYST
HYST
.
.
Value Applies to Fan On/Off Hysteresis and THERM Hysteresis
RANGE
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for
42
Bits [3:0], Local temperature hysteresis (4°C default)
Register 0x6E, Remote 2 Temperature Hysteresis Register
Bits [7:4], Remote 2 temperature hysteresis (4°C default)
below T
the Enhanced Acoustics Register 1 (0x62) allow the fans to
be turned off or to be kept spinning below T
are always on, the T
the temperature drops below T
Bit 5 (MIN1) = 0, PWM1 is off (0% PWM duty cycle) when
temperature is below T
Bit 5 (MIN1) = 1, PWM1 runs at PWM1 minimum duty
cycle below T
Dynamic T
described in the Automatic Fan Control Overview section,
the ADT7473/ADT7473−1 has a mode that extends the
basic automatic fan speed control loop. Dynamic T
In some applications, it is required that fans not turn off
In addition to the automatic fan speed control mode
MIN
MIN
, but remain running at PWM
MIN
Control Mode
− T
HYST
HYST
MIN
value has no effect on the fan when
.
− T
MIN
HYST
.
.
MIN
MIN
. Bits [7:5] of
. If the fans
MIN