ADT7483AARQZ-REEL ON Semiconductor, ADT7483AARQZ-REEL Datasheet - Page 21

• Manufacturer Part Number: ADT7483AARQZ-REEL
• Description: IC TEMP SENSOR/ALARM 3CH 16-QSOP
• Manufacturer: ON Semiconductor

Specifications of ADT7483AARQZ-REEL

• Function: Temp Monitoring System (Sensor)
• Topology: ADC, Comparator, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, External Sensor
• Output Type: SMBus™
• Output Alarm: Yes
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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Pin 13 on the ADT7483A can be configured as either an
ALERT output or as an additional THERM output. THERM2
will assert low when the temperature exceeds the programmed
local and/or remote high temperature limits. It is reset in the
same manner as THERM, and it is not maskable. The programmed
hysteresis value also applies to THERM2. Figure 21 shows how
THERM and THERM2 might operate together to implement two
methods of cooling the system. In this example, the THERM2
limits are set lower than the THERM limits. The THERM2 output
can be used to turn on a fan. If the temperature continues to
rise and exceeds the THERM limits, the THERM output can
provide additional cooling by throttling the CPU.
If the measured temperature exceeds the high temperature
limit, the ALERT output asserts low.
If the temperature continues to increase and exceeds the
THERM limit, the THERM output asserts low. This can
be used to throttle the CPU clock or switch on a fan.
The THERM output deasserts (goes high) when the
temperature falls to THERM limit minus hysteresis. In
Figure 20, the default hysteresis value of 10°C is shown.
The ALERT output deasserts only when the temperature
has fallen below the high temperature limit, and the master
has read the device address and cleared the status register.
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The temperature measurement can be either the local or the
remote temperature measurement.
THERM2
THERM
TEMPERATURE
90°C
80°C
70°C
60°C
50°C
40°C
30°C
When the THERM2 limit is exceeded, the THERM2 signal
asserts low.
If the temperature continues to increase and exceeds the
THERM limit, the THERM output asserts low.
The THERM output deasserts (goes high) when the
temperature falls to THERM limit minus hysteresis. In
Figure 21, there is no hysteresis value shown.
As the system cools further, and the temperature falls
below the THERM2 limit, the THERM2 signal resets.
Again, no hysteresis value is shown for THERM2.
Figure 21. Operation of the THERM and THERM2 Interrupts
1
2
3
4
ADT7483A
THERM LIMIT
THERM2 LIMIT