ADT7462ACPZ-REEL ON Semiconductor, ADT7462ACPZ-REEL Datasheet - Page 39

• 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

Note on 4−Wire Fans
of 2−wire or 3−wire fans. In many cases, 4−wire fans can
start with a PWM drive of as little as 20%.
Step 6—T
on a temperature channel. Above this temperature, a
component such as the CPU or VRM might be operating
beyond its safe operating limit. When the measured
temperature exceeds T
PWM duty cycle (full speed) to provide critical system
cooling. The fans remain running at 100% until the
temperature drops below T
hysteresis is the number programmed into Local/Remote 1
Hysteresis Register 0x54 and Remote 2/Remote 3
Hysteresis Register 0x55. The default hysteresis value is
4°C.
worst−case operating temperature of the system. Because
Figure 62. T
The control range for 4−wire fans is much wider than that
T
The T
THERM
100
100
90
80
70
60
50
40
30
20
10
90
80
70
60
50
40
30
20
10
Ambient, and CPU Temperature Channels
0
0
THERM
0
0
THERM
is the absolute maximum temperature allowed
10
10
RANGE
limit should be considered as the maximum
20
20
for Temperature Channels
and % Fan Speed Slopes for VRM,
TEMPERATURE ABOVE T
TEMPERATURE ABOVE T
30
30
THERM
40
40
THERM
, all fans are driven at 100%
50
50
minus hysteresis, where
60
60
70
MIN
70
MIN
80
80
90
90
http://onsemi.com
100
100
39
exceeding any T
very negative acoustic effects. Ultimately, this limit should
be set up as a fail−safe, and it must not be exceeded under
normal system operating conditions.
affect the fan speed no matter how the automatic fan control
settings are configured. This allows some flexibility because
a T
hard limit (such as 70°C), can be programmed as T
temperature at which the fan reaches full speed) by setting
T
THERM Registers
Register 0x4C, Local THERM1 temperature limit = 0xA4
(100°C default)
Register 0x4D, Remote 1 THERM1 temperature limit = 0xA4
(100°C default)
Register 0x4E, Remote 2 THERM1 temperature limit = 0xA4
(100°C default)
Register 0x4F Remote 3 THERM1 temperature limit = 0xA4
(100°C default)
Register 0x50, Local THERM2 temperature limit = 0xA4
(100°C default)
Register 0x51, Remote 1 THERM2 temperature limit = 0xA4
(100°C default)
Register 0x52, Remote 2 THERM2 temperature limit = 0xA4
(100°C default)
Register 0x53 Remote 3 THERM2 temperature limit = 0xA4
(100°C default)
Hysteresis Registers
Register 0x54, Local/Remote 1 Temperature Hysteresis
Register
Bits [7:4], local temperature hysteresis (4°C default)
Bits [3:0], Remote 1 temperature hysteresis (4°C default)
Register 0x55, Remote 2/Remote 3 Temperature
Hysteresis Register
Bits [7:4], Remote 2 temperature hysteresis (4°C default)
Bits [3:0], Remote 3 temperature hysteresis (4°C default)
values are programmable from 1°C to 15°C. It is not
recommended that hysteresis values ever be programmed to
0°C, because this value disables hysteresis. In effect, this
value causes the fans to cycle between normal speed and
100% speed, creating unsettling acoustic noise.
THERM
Note that the T
Because each hysteresis setting is four bits, hysteresis
RANGE
to that limit (for example, 70°C).
value can be selected based on its slope, while a
THERM
THERM
limit runs all fans at 100%, it has
limits cannot be masked, and they
MAX
(the