ADT7462ACPZ-5RL7 ON Semiconductor, ADT7462ACPZ-5RL7 Datasheet - Page 36

• Manufacturer Part Number: ADT7462ACPZ-5RL7
• Description: IC TEMP/VOLT MONITOR 32-LFCSP
• Manufacturer: ON Semiconductor

Specifications of ADT7462ACPZ-5RL7

• 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
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 3 V
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ADT7462ACPZ-500RL7; ADT7462ACPZ-500RL7; ADT7462ACPZ-500RL7TR; ADT7462ACPZ-500RL7TR; ADT7462ACPZ-5RL7TR

Programming the PWM
minimum PWM duty cycle for each output to be configured
anywhere from 0% to 100%. This allows the minimum
PWM duty cycle to be set in steps of 0.39%.
given by:
Example 1: For a minimum PWM duty cycle of 50%,
Example 2: For a minimum PWM duty cycle of 33%,
PWM
Register 0x28, Minimum PWM1 Duty Cycle = 0x80
(50% default)
Register 0x29, Minimum PWM2 Duty Cycle = 0x80
(50% default)
Register 0x2A, Minimum PWM3 Duty Cycle = 0x80
(50% default)
Register 0x2B, Minimum PWM4 Duty Cycle = 0x80
(50% default)
Note on Fan Speed and PWM Duty Cycle
speed in rpm. Running a fan at 33% PWM duty cycle does
not equate to running the fan at 33% speed. Driving a fan at
33% PWM duty cycle actually runs the fan at closer to 50%
of its full speed. This is because fan speed in % rpm
generally relates to the square root of PWM duty cycle.
Given a PWM square wave as the drive signal, fan speed in
rpm approximates to:
Step 4—PWM
system runs at under the automatic fan speed control loop.
For maximum system acoustic benefit, PWM
as low as possible but should be capable of maintaining the
processor temperature limit at an acceptable level. If the
THERM temperature limit is exceeded, the fans are still
boosted to 100% for fail−safe cooling.
channels.
The PWM
The value to be programmed into the PWM
The PWM duty cycle does not directly correlate to fan
PWM
There is one PWM
Value (decimal) = PWM
Value (decimal) = 50/0.39 = 128 (decimal)
Value = 128 (decimal) or 0x80 (hexadecimal)
Value (decimal) = 33/0.39 = 85 (decimal)
Value = 85 (decimal) or 0x54 (hexadecimal)
MIN
MAX
Registers
MIN
is the maximum duty cycle that each fan in the
MAX
registers are 8−bit registers that allow the
% fanspeed + PWM duty cycle
for PWM (Fan) Outputs
MAX
MIN
limit (Register 0x2C) for all fan
Registers
MIN
/0.39
MAX
MIN
register is
should be
http://onsemi.com
10
36
Programming the PWM
allows the maximum PWM duty cycle for the outputs to be
configured anywhere from 0% to 100%. This allows the
maximum PWM duty cycle to be set in steps of 0.39%.
is given by:
Example 1: For a maximum PWM duty cycle of 50%,
Example 2: For a maximum PWM duty cycle of 75%,
PWM
Register 0x2C, Maximum PWM1 to PWM4 Duty Cycle =
0xC0 (75% default)
for more information.
Step 5—T
automatic fan control occurs when the programmed T
temperature is exceeded. T
an arbitrary value; that is, a T
for PWM
the effective T
Figure 56. PWM
Figure 57. T
The PWM
The value to be programmed into the PWM
See the Note on Fan Speed and PWM Duty Cycle section
T
RANGE
Value (decimal) = PWM
Value (decimal) = 50/0.39 = 128 (decimal)
Value = 128 (decimal) or 0x80 (hexadecimal)
Value (decimal) = 75/0.39 = 192 (decimal)
Value = 192 (decimal) or 0xC0 (hexadecimal)
MAX
Cycle Below the THERM Temperature Limit
PWM
PWM
PWM
MIN
Register
RANGE
100%
100%
MAX
is the range of temperatures over which
MIN
0%
MIN
0%
MAX
= 33%. If PWM
RANGE
RANGE
for Temperature Channels
MAX
register (0x2C) is an 8−bit register that
T
T
Parameter Affects Cooling Slope
MIN
MIN
changes.
Determines Maximum PWM Duty
MAX
RANGE
RANGE
MAX
Register
MIN
T
is a temperature slope, not
/0.39
RANGE
is increased or decreased,
TEMPERATURE
TEMPERATURE
of 40°C holds true only
MAX
register
MIN