ADT7483AARQZ-R7 View Datasheet(PDF) - ON Semiconductor

Part Name

Description

MFG CO.

ADT7483AARQZ-R7

Dual Channel Temperature Sensor and Over Temperature Alarm

ON Semiconductor 

• 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.

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.

ADT7483A

TEMPERATURE

90°C

80°C

70°C

60°C

50°C

40°C

30°C

THERM LIMIT

THERM2 LIMIT

1

4

THERM2

THERM

2

3

Figure 21. Operation of the THERM and THERM2 Interrupts

• 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.

The temperature measurement can be either the local or the

remote temperature measurement.

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