GENERAL DESCRIPTION

The AD22103 is a monolithic temperature sensor with on-chipsignal conditioning.It can be operated over the temperaturerange 0℃ to+100°℃,making it ideal for use in numerous 3.3Vapplications.

The signal conditioning eliminates the need for any trimming,buffering or linearization circuitry,greatly simplifying the systemdesign and reducing the overall system cost.

The output voltage is proportional to the temperature times thesupply voltage(ratiometric).The output swings from 0.25Vat0℃ to+3.05V at+100℃ using a single+3.3Vsupply.

Due to its ratiometric nature,the AD22103 offers a cost effec-tive solution when interfacing to an analog-to-digital converter.This is accomplished by using the ADC’s power supply as a ref-erence to both the ADC and the AD22103,eliminating the need for and cost of a precision reference.

 

ОСОБЕННОСТИ

3.3 V,Single Supply Operation

Temperature Coefficient of 28mV/℃

100℃ Temperature Span (0℃ to+100°℃)

Accuracy Better Than 2.5%of Full Scale

Linearity Better Than 0.5%of Full Scale

Output Proportional to Temperature×Vs

Minimal Self-Heating

High Level,Low Impedance Output

Reverse Supply Protected

 

ПРИЛОЖЕНИЯ

Microprocessor Thermal Management

Battery and Low Powered Systems

Power Supply Temperature Monitoring

System Temperature Compensation

Board Level Temperature Sensing

 

MARKETS

Компьютеры

Portable Electronic Equipment

Управление промышленными процессами

Приборы

 

CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection.Although the AD22103 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.

 

AD22103

ТЕОРИЯ ЭКСПЛУАТАЦИИ

The AD22103 is a ratiometric temperature sensor IC whose output voltage is proportional to power supply voltage. The heart of the sensor is a proprietary temperature-dependent resistor, similar to an RTD, which is built into the IC.

 

OUTPUT STAGE CONSIDERATIONS

As previously stated, the AD22103 is a voltage output device. A basic understanding of the nature of its output stage is useful for proper application. Note that at the nominal supply voltage of  3.3 V, the output voltage extends from 0.25 V at 0°C to +3.05 V at +100°C. Furthermore, the AD22103 output pin is capable of withstanding an indefinite short circuit to either ground or the power supply.

 

MOUNTING CONSIDERATIONS

If the AD22103 is thermally attached and properly protected, it can be used in any measuring situation where the maximum range of temperatures encountered is between 0°C and +100°C. Because plastic IC packaging technology is employed, excessive mechanical stress must be avoided when fastening the device with a clamp or screw-on heat tab. Thermally conductive epoxy or glue is recommended for typical mounting conditions. In wet or corrosive environments, an electrically isolated metal or ceramic well should be used to shield the AD22103. Because the part has a voltage output (as opposed to current), it offers modest immunity to leakage errors, such as those caused by condensation at low temperatures.

 

THERMAL ENVIRONMENT EFFECTS

The thermal environment in which the AD22103 is used determines two performance traits: the effect of self-heating on accuracy and the response time of the sensor to rapid changes in temperature. In the first case, a rise in the IC junction temperature above the ambient temperature is a function of two variables;the power consumption of the AD22103 and the thermal resistance between the chip and the ambient environment θJA. Selfheating error in degrees Celsius can be derived by multiplying the power dissipation by θJA. Because errors of this type can vary widely for surroundings with different heat sinking capacities, it is necessary to specify θJA under several conditions. Table I shows how the magnitude of self-heating error varies relative to the environment. A typical part will dissipate about 1.5 mW at room temperature with a 3.3 V supply and negligible output loading. In still air, without a “heat sink,” the table below indicates a θJA of 190°C/W, yielding a temperature rise of 0.285°C. Thermal rise will be considerably less in either moving air or with direct physical connection to a solid (or liquid) body.