ADT7462ACPZ-REEL ON Semiconductor, ADT7462ACPZ-REEL Datasheet - Page 33

• Manufacturer Part Number: ADT7462ACPZ-REEL
• Description: IC TEMP/VOLT MONITOR 32-LFCSP
• Manufacturer: ON Semiconductor

Specifications of ADT7462ACPZ-REEL

• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, 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 ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 32-LFCSP
• Number Of Voltages Monitored: 1
• Monitored Voltage: 0.9 V to 12 V
• Manual Reset: Not Resettable
• Watchdog: No Watchdog
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 3 V
• Supply Current (typ): 4000 uA
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Step 1—Configuring the MUX
channels are being measured and how many fans need to be
controlled and monitored. When these decisions have been
made, the fans can be assigned to particular temperature
channels. Not only can fans be assigned to individual
channels, but the behavior of the fans is also configurable.
For example, fans can be run under automatic fan control;
they can be run manually (under software control) or they
can be run at the fastest speed calculated by multiple
temperature channels. The MUX is the bridge between
temperature measurement channels and the three PWM
outputs.
Register 0x23, and Register 0x24 (PWM configuration
registers) control the behavior of the fans connected to the
PWM1, PWM2, PWM3, and PWM4 outputs. The values
selected for these bits determine how the MUX connects a
temperature measurement channel to a PWM output (see
Figure 52).
Automatic Fan Control MUX Options
Register 0x23, and Register 0x24, control the behavior of the
corresponding PWM outputs (see Table 57 and Table 58).
First, the user needs to decide how many temperature
Bits [7:5] (BHVR) of Register 0x21, Register 0x22,
Bits [7:5] (BHVR), of Register 0x21, Register 0x22,
REMOTE 1
REMOTE 2
LOCAL
TEMP
TEMP
TEMP
THERMAL CALIBRATION
THERMAL CALIBRATION
THERMAL CALIBRATION
T
T
T
MIN
MIN
MIN
Figure 51. Automatic Fan Control Block Diagram
T
T
T
RANGE
RANGE
RANGE
100%
100%
100%
0%
0%
0%
http://onsemi.com
MUX
33
one PWM output based on multiple temperature channels.
The thermal characteristics of the three temperature zones
can be set to drive a single fan. An example is the fan turning
on when the Remote 1 temperature exceeds 60°C or when
the local temperature exceeds 45°C.
Step 2—T
Channels
under automatic fan control. The speed at which the fan runs
at T
temperature channel−specific; for example, 25°C for
ambient channel, 30°C for VRM temperature, and 40°C for
processor temperature.
64, that can be programmed in 1°C increments. There is a
T
channel: local, Remote 1, Remote 2, and Remote 3. When the
T
minimum PWM duty cycle. The fan turns off after the
temperature has dropped below T
MIN
MIN
PWM
PWM
PWM
The fastest speed calculated options pertain to controlling
T
T
MIN
MIN
MIN
MIN
MIN
MIN
register associated with each temperature measurement
value is exceeded, the fan turns on and runs at the
is an 8−bit value, either twos complement or Offset
ENHANCEMENT)
ENHANCEMENT)
ENHANCEMENT)
is the temperature at which the fans start to turn on
TACHOMETER 1
MEASUREMENT
TACHOMETER 2
MEASUREMENT
TACHOMETER 3
MEASUREMENT
is programmed later. The T
(ACOUSTIC
(ACOUSTIC
(ACOUSTIC
MIN
CONTROL
CONTROL
CONTROL
RAMP
RAMP
RAMP
AND 4
Settings for Thermal Calibration
GENERATOR
GENERATOR
GENERATOR
CONFIG
CONFIG
CONFIG
PWM
PWM
PWM
PWM
PWM
PWM
MIN
MIN
− T
PWM1
TACH1
PWM2
TACH2
TACH3
PWM3
values chosen are
HYST
.