ADT7476ARQZ ON Semiconductor, ADT7476ARQZ Datasheet - Page 37

• Manufacturer Part Number: ADT7476ARQZ
• Description: IC REMOTE THERMAL CTRLR 24QSOP
• Manufacturer: ON Semiconductor
• Series: dBCool®r

Specifications of ADT7476ARQZ

• 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: 24-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

Mux Configuration Example
system using the ADT7476 to control three fans. The CPU
fan sink is controlled by PWM1, the front chassis fan is
controlled by PWM2, and the rear chassis fan is controlled
by PWM3. The mux is configured for the following fan
control behavior:
•
•
This is an example of how to configure the mux in a
PWM1 (CPU fan sink) is controlled by the fastest speed
calculated by the local (VRM temperature) and
Remote 2 (processor) temperature. In this case, the
CPU fan sink is also being used to cool the VRM.
PWM2 (front chassis fan) is controlled by the Remote 1
temperature (ambient).
AMBIENT TEMP
REMOTE 2 =
REMOTE 1 =
VRM TEMP
CPU TEMP
LOCAL =
THERMAL CALIBRATION
THERMAL CALIBRATION
THERMAL CALIBRATION
T
T
T
MIN
MIN
MIN
T
T
T
RANGE
RANGE
RANGE
Figure 52. Mux Configuration Example
100%
100%
100%
0%
0%
0%
MUX
http://onsemi.com
37
PWM
PWM
PWM
MIN
MIN
MIN
•
Example Mux Settings
[7:5] (BHVR), PWM1 Configuration Register (0x5C).
[7:5] (BHVR), PWM2 Configuration Register (0x5D).
[7:5] (BHVR), PWM3 Configuration Register (0x5E).
CONFIG
CONFIG
CONFIG
These settings configure the mux, as shown in Figure 52.
PWM3 (rear chassis fan) is controlled by the Remote 1
temperature (ambient).
TACHOMETER 1
MEASUREMENT
TACHOMETER 2
MEASUREMENT
TACHOMETER 3
MEASUREMENT
PWM
PWM
PWM
101 = Fastest speed calculated by local and Remote 2
000 = Remote 1 temperature controls PWM2
000 = Remote 1 temperature controls PWM3
GENERATOR
GENERATOR
GENERATOR
AND 4
PWM
PWM
PWM
temperature controls PWM1
ENHANCEMENT)
ENHANCEMENT)
ENHANCEMENT)
(ACOUSTIC
(ACOUSTIC
(ACOUSTIC
CONTROL
CONTROL
CONTROL
RAMP
RAMP
RAMP
PWM1
TACH1
PWM2
TACH2
PWM3
TACH3
FRONT CHASSIS
REAR CHASSIS
CPU FAN SINK