Electronic Components Datasheet Search |
|
ADT6502SRJZP105RL7 Datasheet(PDF) 10 Page - Analog Devices |
|
ADT6502SRJZP105RL7 Datasheet(HTML) 10 Page - Analog Devices |
10 / 16 page ADT6501/ADT6502/ADT6503/ADT6504 Data Sheet Rev. B | Page 10 of 16 APPLICATION INFORMATION THERMAL RESPONSE TIME The time required for a temperature sensor to settle to a specified accuracy is a function of the sensor’s thermal mass and the thermal conductivity between the sensor and the object being sensed. Thermal mass is often considered equivalent to capacitance. Thermal conductivity is commonly specified using the symbol Q and can be thought of as thermal resistance. It is commonly specified in units of degrees per watt of power transferred across the thermal joint. Thus, the time required for the ADT650x to settle to the desired accuracy is dependent on the characteristics of the SOT-23 package, the thermal contact established in that particular application, and the equivalent power of the heat source. In most applications, the settling time is best determined empirically. SELF-HEATING EFFECTS The temperature measurement accuracy of the ADT6501/ ADT6502/ADT6503/ADT6504 can be degraded in some applications due to self-heating. Errors can be introduced from the quiescent dissipation and power dissipated when converting. The magnitude of these temperature errors depends on the thermal conductivity of the ADT650x package, the mounting technique, and the effects of airflow. At 25°C, static dissipation in the ADT650x is typically 99 µW operating at 3.3 V. In the 5-lead SOT-23 package mounted in free air, this accounts for a temperature increase due to self-heating of ΔT = PDISS × θJA = 99 µW × 240°C/W = 0.024°C It is recommended that current dissipated through the device be kept to a minimum because it has a proportional effect on the temperature error. SUPPLY DECOUPLING The ADT6501/ADT6502/ADT6503/ADT6504 should be decoupled with a 0.1 µF ceramic capacitor between VCC and GND. This is particularly important when the ADT650x are mounted remotely from the power supply. Precision analog products such as the ADT650x require well filtered power sources. Because the ADT650x operate from a single supply, it may seem convenient to tap into the digital logic power supply. Unfortunately, the logic supply is often a switch-mode design, which generates noise in the 20 kHz to 1 MHz range. In addition, fast logic gates can generate glitches that are hundreds of mV in amplitude due to wiring resistance and inductance. If possible, the ADT650x should be powered directly from the system power supply. This arrangement, shown in Figure 19, isolates the analog section from the logic switching transients. Even if a separate power supply trace is not available, generous supply bypassing reduces supply line induced errors. Local supply bypassing consisting of a 0.1 µF ceramic capacitor is advisable to achieve the temperature accuracy specifications. This decoupling capacitor must be placed as close as possible to the ADT650x VCC pin. Figure 19. Separate Traces Used to Reduce Power Supply Noise TEMPERATURE MONITORING The ADT6501/ADT6502/ADT6503/ADT6504 are ideal for monitoring the thermal environment within electronic equipment. For example, the surface-mount package accurately reflects the exact thermal conditions that affect nearby integrated circuits. The ADT650x measure and convert the temperature at the surface of its own semiconductor chip. When the ADT650x are used to measure the temperature of a nearby heat source, the thermal impedance between the heat source and the ADT650x must be as low as possible. As much as 60% of the heat transferred from the heat source to the thermal sensor on the ADT650x die is discharged via the copper tracks, package pins, and bond pads. Of the pins on the ADT650x, the GND pins transfer most of the heat. Therefore, to monitor the temperature of a heat source, it is recommended that the thermal resistance between the ADT650x GND pins and the GND of the heat source be reduced as much as possible. For example, the unique properties of the ADT650x can be used to monitor a high power dissipation microprocessor. The ADT650x device in its SOT-23 package is mounted directly beneath the microprocessor’s pin grid array (PGA) package. The ADT650x requires no external characterization. 0.1µF ADT650x TTL/CMOS LOGIC CIRCUITS POWER SUPPLY |
Similar Part No. - ADT6502SRJZP105RL7 |
|
Similar Description - ADT6502SRJZP105RL7 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |