ADT6501 AD | Alldatasheet

Document overview

  • Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
  • PDF pages: 16

Technical content

Low Cost, 2.7 V to 5.5 V, Micropower Temperature Switches in SOT-23 Preliminary Technical Data ADT6501/ADT6502/ADT6503/ADT6504 Rev. PrA Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 © 2006 Analog Devices, Inc. All rights reserved.

FEATURES

±0.5°C (typ) accuracy over temperature range Factory set trip points from −45°C to +15°C in 10°C increments Factory set trip points from +35°C to +115°C in 10°C increments No external components required Max temperature of +125°C Open-drain output (ADT6501/ADT6503) Push-pull output (ADT6502/ADT6504) Pin selectable hysteresis of 2°C and 10°C Supply current of 30 μA (typ) Space saving 5-lead SOT23 package

APPLICATIONS

Σ-Δ DIGITAL COMPARATOR TOVER VCC GND HYST TEMPERATURE SENSOR 1-BIT 12-BIT DECIMATOR 1-BIT DAC REFERENCE – 5 FACTORY PRESET TRIP POINT REGISTER GND 2°C/10°C 06096-001 Figure 1. GENERAL DESCRIPTION The ADT6501/ADT6502/ADT6503/ADT6504 are trip point temperature switches available in a 5-lead SOT23 package. It contains an internal band gap temperature sensor for local temperature sensing. When the temperature crosses the trip point setting, the logic output is activated. The ADT6501/ ADT6503 logic output is active low and open-drain. The ADT6502/ADT6504 logic output is active high and push-pull. The temperature is digitized to a resolution of +0.0625°C (12 bit). The factory settings are 10°C apart starting from −45°C to +15°C for the cold threshold models and from +35°C to +115°C for the hot threshold models. These devices require no external components and typically consume 30μA supply current. Hysteresis is pin selectable at 2°C and 10°C. The temperature switch is specified to operate over the supply range of 2.7 V to 5.5 V . ADT6501 and ADT6502 are used for monitoring temperatures from +35°C to +115°C only. Hence, the logic output pin becomes active when the temperature goes higher than the selected trip point temperature. The ADT6503 and ADT6504 are used for monitoring temperatures from −45°C to +15°C only. Hence, the logic output pin becomes active when the temperature goes lower than the selected trip point temperature. PRODUCT HIGHLIGHTS 1. ±0.5°C typical from −55°C to +125°C. 2. Factory threshold settings from −45°C to +115°C in 10°C increments 3. Supply voltage is 2.7 V to 5.5 V . 4. Supply current of 30 μA. 5. Space-saving 5-lead SOT23 package. 6. Pin selectable temperature hysteresis of 2°C or 10°C. 7. Temperature resolution of 0.0625°C.

ADT6501/ADT6502/ADT6503/ADT6504 Preliminary Technical Data Rev. PrA | Page 2 of 16 TABLE OF CONTENTS

Preliminary Technical Data ADT6501/ADT6502/ADT6503/ADT6504 Rev. PrA | Page 3 of 16 SPECIFICATIONS Table 1. Parameter Min Typ Max Unit Test Conditions/Comments TEMPERATURE SENSOR AND ADC Threshold Accuracy at VCC = 2.7 V to 5.5 V ADC Resolution 12 Bits Temperature Conversion Time 30 ms Time necessary to complete a conversion Update Rate 600 ms Conversion started every 600 ms Long Term Drift 0.08 °C Drift over 10 years, if part is operated at +55°C Temperature Hysteresis +0.03 °C Temperature cycle = 25°C to 125°C to 25°C Temperature Threshold Hysteresis 2 °C 10 °C DIGITAL INPUT (HYST) Input Low Voltage, VIL 0.2 × VCC V Input High Voltage, VIH 0.8 × VCC V DIGITAL OUTPUT (OPEN-DRAIN) Output High Current, IOH 10 nA Leakage current, Vcc = 2.7 V and VOH = 5.5 V Output Low Voltage, VOL 0.3 V IOL = 1.2 mA, Vcc = 2.7 V Output Low Voltage, VOL 0.4 V IOL = 3.2 mA, Vcc = 4.5 V Output Capacitance, COUT1 10 pF DIGITAL OUTPUT (Push-Pull) Output Low Voltage, VOL 0.3 V IOL = 1.2 mA, Vcc = 2.7 V Output Low Voltage, VOL 0.4 V IOL = 3.2 mA, Vcc = 4.5 V Output High Voltage, VOH 0.8 × VCC V ISOURCE = 500 μA, VCC = 2.7 V Output High Voltage, VOH VCC – 1.5 V ISOURCE = 800 μA, VCC = 4.5 V Output Capacitance, COUT11 10 pF POWER REQUIREMENTS Supply Voltage 2.7 5.5 V Supply Current 30 85 μA 1 Guaranteed by design and characterization.

worst case θJA. Refer to Figure 2 for a plot of maximum power dissipation vs.

3 Junction-to-case resistance is applicable to components featuring a

Figure 2. SOT-23 Maximum Power Dissipation vs. Temperature degradation or loss of functionality.

Figure 3. ADT6501/ADT6502 Pin Configuration Figure 4. ADT6503/ADT6504 Pin Configuration Table 3. Pin Function Descriptions 4 4 VCC Supply Input (+2.7 V to +5.5 V). part exceeds the factory programmed threshold; must use a pull-up resistor. part exceeds the factory programmed threshold. the part exceeds the factory programmed threshold.

ADT650x family is ±6°C from −45°C to +115°C. completed. This typically takes 30 ms. of effective accuracy in an extremely compact circuit. the comparator output in response to input voltage changes. overall noise performance and increasing accuracy. Figure 14. First-Order ∑-Δ Modulator circuit technique that results in SMBus/I2C temperature data. applications, such as fan control circuits. available temperature threshold ranges. Table 4. Factory Set Temperature Threshold Ranges the temperature is approaching the trip point, after it activates. 35°C before the output deactivates.

ADT6501/ADT6502/ADT6503/ADT6504 Preliminary Technical Data Rev. PrA | Page 10 of 16

APPLICATION INFORMATION

The time required for a temperature sensor to settle to a specified accuracy is a function of the thermal mass of the sensor 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 ADT6501/ADT6502/ADT6503/ADT6504 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 probably 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 is dependent 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 TBD 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 = TBD μW × 240°C/W = TBD°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 VDD and GND. This is particularly important when the ADT650x are mounted remotely from the power supply. Precision analog products, such as the ADT650x, require a well-filtered power source. Because the ADT650x operate from a single supply, it might 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 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 for the temperature accuracy specifications to be achieved. This decoupling capacitor must be placed as close as possible to the ADT650x V CC pin. 0.1µF ADT650x TTL/CMOS LOGIC CIRCUITS POWER SUPPLY 06096-010 Figure 19. Use Separate Traces to Reduce Power Supply Noise

Preliminary Technical Data ADT6501/ADT6502/ADT6503/ADT6504 Rev. PrA | Page 11 of 16 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 is reduced as much as possible. For example, use the unique properties of the ADT650x 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.

0.95 BSC

0.15 MAX SEATING

1.45 MAX

2.90 BSC

Figure 20. 5-Lead Small Outline Transistor Package [SOT-23]

Preliminary Technical Data ADT6501/ADT6502/ADT6503/ADT6504 Rev. PrA | Page 13 of 16 NOTES

ADT6501/ADT6502/ADT6503/ADT6504 Preliminary Technical Data Rev. PrA | Page 14 of 16 NOTES

Preliminary Technical Data ADT6501/ADT6502/ADT6503/ADT6504 Rev. PrA | Page 15 of 16 NOTES

ADT6501/ADT6502/ADT6503/ADT6504 Preliminary Technical Data Rev. PrA | Page 16 of 16 NOTES Purchase of licensed I2C components of Analog Devices or one of its sublicensed Associated Companies conveys a license for the purchaser under the Philips I2C Patent Rights to use these components in an I2C system, provided that the system conforms to the I2C Standard Specification as defined by Philips. ©2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. PR06096-0-10/06(PrA)