DIA1412

Version 1.0, Jul 2024

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9. Function Description

The DIA1412 is temperature sensor chip compatible with SMBus (or I2C) communication protocol. The chip can

monitor one internal temperature and can also monitor one external channel. The external channel can support

both PNP and diode-connected NPN temperature monitoring. The

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ALERT or

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THERM /ADDR pin can be

asserted to achieve two levels of overtemperature alarm.

9.1. Operating modes

The DIA1412 have two operating modes, standby and active.

In the standby mode, the chip supports SMBus and I2C but does not conduct consecutive temperature detection.

Every time the one shot register is written (see section 12.7), the device detects all temperature channels for

once. After the temperature detection is completed, the device enters the standby mode again.

In the active mode, the chip performs consecutive temperature detection and updates the temperature data in

the registers and the value of the status registers (see section 12.2) in real-time. This is the default state.

9.2. External temperature detection

The DIA1412 can automatically detect whether the externally connected BJT is NPN or PNP. If the BJT is PNP,

the chip will automatically detect the beta value of PNP to configure the appropriate working state, so as to

achieve the high accuracy of temperature measurement (see section 12.1).

When the external PNP for temperature monitoring is a parasitic PNP with a low beta value, which will greatly

affect the accuracy of temperature measurement, the Beta Compensation will be enabled to reduce the

temperature errors.

In applications, the temperature measurement accuracy may be affected by the series resistances introduced by

the long trace on the PCB and the welding resistances at the ports. The Resistance Error Correction integrated

into the DIA1412 can minimize the temperature errors caused by these series resistances.

The non-ideal factor, η, varies with different types of BJTs will also affect the accuracy of external temperature

measurement. The DIA1412 has individual non-ideal factor configuration register for each channel (see section

12.3), the value of which can be programmed by the user to obtain accuracy temperature monitoring.

9.3. Overtemperature alarm

The DIA1412 has

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THERM /ADDR output pin and

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ALERT output pin for overtemperature alarm or fault event.

Both

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THERM/ADDR and

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ALERT pins are open-drain outputs and require pull-up resistors.

9.3.1.

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ALERT pin

The

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ALERT pin is an open-drain output, so that a pull-up resistor is needed. It has two modes of operation,

named “Interrupt mode” and “Comparator mode”, which can be selected via the ALERT/COMP bit in the

configuration register (see section 12.3).