Serial Bus or Voltage Out Silicon Temperature Sensing

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The MCP9700/9700A family of Linear Active Thermistor™ Intergrated Circuits (IC) are analog temperature sensors that convert temperature to analog voltage. Unlike resistive sensors (such as thermistors), the Linear Active Thermistor IC does not require an additional signal conditioning circuit. Therefore, the biasing circuit development overhead for thermistor solutions can be avoided by implementing this low cost device.

The MCP9800/1/2/3 family comes with user-programmable registers that provide flexibility for temperature sensing applications.

 

FEATURES - MCP9700/9700A Available packages: SC-70-5, SOT-23-5, TO-92-3 Wide temperature measurement range: -40°C to +125°C Accuracy - ±2°C (max.), 0°C to +70°C (MCP9700A) - ±4°C (max.), 0°C to +70°C (MCP9700) Optimized for analog-to-digital converters (ADCs) - 10.0mV/°C (typical) MCP9700/9700A Wide operating voltage range: VDD = 2.3V to 5.5V Low operating current: 6µA (typical)

APPLICATIONS Hard disk drives and other PC peripherals Entertainment systems Home appliances Office equipment Battery packs and portable equipment General purpose temperature monitoring

 

 

FEATURES – MCP9800/1/2/3 Accuracy with 12-bit resolution - ±0.5°C (typ.) at +25°C - ±1°C (max.) from -10°C to +85°C - ±2°C (max.) from -10°C to +125°C - ±3°C (max.) from -55°C to +125°C User-selectable resolution: 9-12-bit Operating voltage range: 2.7V to 5.5V 2-wire interface: I2C™/SMBus compatible Operating current: 200µA (typ.)

APPLICATIONS PC and peripherals Entertainment systems Office equipment Data communication equipment General purpose temperature monitoring

 

 

Linear Active Thermistor™ ICs are sensors whose output voltage is directly proportional to measured temperature. The MCP9700A can accurately measure temperature from -40ºC to +125ºC. The output of the MCP9700A is calibrated to a slope of 10mV/°C and has a DC offset of 500mV. The offset allows reading negative temperatures without the need for a negative supply. The MCP9700A is packaged in space saving 5-pin SC-70, and 3-ld TO-92 packages.

Parameter Name	Value
Typical Accuracy (°)	1
Max Input/ Supply Current (µA)	6
Max. Accuracy @ 25° (°)	2
Temp. Range (°C)	-40 to +125
Operating Voltage Range (V)	2.3 to 5.5

 

The MCP9800/1/2/3 are digital temperature sensors capable of reading temperatures from -55°C to +125°C. Temperature data is measured from an integrated temperature sensor and converted to digital word with a user selectable 9 to 12-bit Sigma Delta Analog to Digital Converter. The MCP9800/1/2/3 notifies the host controller when the ambient temperature exceeds a user programmed set point. The ALERT output is programmable as either a simple comparator for thermostat operation or as a temperature event interrupt. Communication with the sensor is accomplished via a two-wire bus that is compatible with industry standard protocols. This permits reading the current temperature, programming the set point and hysteresis and configuring the device. Small physical size, low installed cost and ease of use make the MCP9800/1/2/3 an ideal choice for implementing sophisticated temperature system management schemes in a variety of applications.

Parameter Name	Value
Typical Accuracy (°)	0.5
Max Input/ Supply Current (µA)	400
Max. Accuracy @ 25° (°)	1
Temp. Range (°C)	-55 to +125
Operating Voltage Range (V)	+2.7 to +5.5

 

 

Application Notes

IC Temperature Sensor Accuracy Compensation with a PICmicro Microcontroller (PDF)

This application note is based on the analog output MCP9700/MCP9701 and serial output MCP9800 temperature sensors

 

Temperature Sensing Technologies (PDF)

Of all of the sensing technologies, temperature sensing is the most common. This phenomenon can be explained by citing examples in a multitude of applications where knowing and using the actual or relative temperature is critical. For instance, other sensors such as pressure, force, flow, level, and position many times require temperature monitoring in order to insure accuracy. As an example, pressure and force are usually sensed with resistive Wheatstone bridge configurations. The temperature errors of the resistive elements of these bridges can exceed the actual measurement range of the sensor, making the pressure sensor’s output fairly useless, unless the temperature of the bridge is known. Flow and level sensor accuracies are dependent on the density of the liquid or gas.

 

Interfacing a MCP9700 Analog Temperature Sensor to a PICmicro Microcontroller (PDF)

Analog output silicon temperature sensors offer an easy-to-use alternative to traditional temperature sensors, such as thermistors. The MCP9700 offers many system-level advantages, including the integration of the temperature sensor and signal-conditioning circuitry on a single chip. Analog output sensors are especially suited for embedded systems due to their linear output. This application note will discuss system integration, firmware implementation and PCB layout techniques for using the MCP9700 in an embedded system. The firmware required to interface the MCP9700 to a microcontroller will be demonstrated using the PICkit™ 1 Flash Starter Kit. The PICkit 1 Flash Starter Kit is a low-cost development kit with an easy-to-use interface for programming Microchip’s 8-pin and 14-pin Flash family of microcontrollers. The MCP9700 demonstration is designed to measure and display temperature in Binary-Coded Decimal (BCD) with the PICkit 1 Flash Starter Kit’s LEDs. Temperature data is converted from the internal thermal sensing element and made available as an analog output voltage.

 

Interfacing the MCP9800 I²C Digital Temperature Sensor to a PICmicro Microcontroller (PDF)

This application note will discuss system integration, firmware implementation and PCB layout techniques for using the MCP9800 in an embedded system.

 

Temperature-to-Voltage Converter PICtail™ Demo Board - MCP9700DM-PCTL

The MCP9700 Temperature-to-Voltage Converter PICtail™ Demo Board demonstrates how to interface the MCP9700 to a microcontroller. This can be used by the system designer as an example of how to integrate an analog temperature sensor into systems.

 

FEATURES Firmware that uses PIC16F676 to measure and display temperature in degree Fahrenheit or Celsius Small PCB layout Standard 100 mil 14-pin header (P1) for easy interface to PICkit™ 1 Flash Starter Kit or custom application

 

Temperature Sensor PICtail Demo Board - MCP9800DM-PCTL

The MCP9800 Thermal Sensor PICtail™ Demo Board demonstrates how to interface the MCP9800 to a PICmicro® microcontroller using the PICkit™ 1 Flash Starter Kit as a platform. The kit includes:

• A PIC16F684 14-pin Flash-based 8-bit CMOS microcontroller that can be used with PICkit™ 1 Flash Starter Kit
• Firmware that provides the I²C™ interface and temperature conversion routines to communicate with the MCP9800 and convert serial data to temperature data

The MCP9800 Thermal Sensor PICtail Demo Board can also be used as a stand-alone module to quickly add thermal sensing capability to any existing application. This basic sensor functionality is implemented on a small Printed Circuit Board (PCB) and an interface via a standard 100 mil header.

 

FEATURES Standard 100 mil 14-pin header (J2) for easy interface to PICkit™ 1 Flash Starter Kit or custom application 7-segment LED display to display temperature in °C or °F Temperature Alert indicating LED Small PCB layout

 

 Featured Products

Part Number		Description	Data Sheet	App. Notes
MCP9700AT-E/LT		Low-Power Linear Active Thermistor™ IC
MCP9700DM-PCTL		MCP9700 Temperature-to-Voltage Converter PICtail Demo Board
MCP9700-E/TO		Low-Power Linear Active Thermistor™ ICs
MCP9700T-E/LT		Low-Power Linear Active Thermistor™ IC
MCP9800A0T-M/OTG		2-Wire High-accuracy Temperature Sensor
MCP9800A5T-M/OT		2-Wire High-accuracy Temperature Sensor
MCP9800DM-PCTL		MCP9800 Thermal Sensor PICtail Demo Board
MCP9801-M/MS		2-Wire High-accuracy Temperature Sensor
MCP9801T-M/SN		2-Wire High-accuracy Temperature Sensor
MCP9802A0T-M/OT		2-Wire High-accuracy Temperature Sensor
MCP9802A5T-M/OT		2-Wire High-accuracy Temperature Sensor
MCP9803-M/SN		2-Wire High-accuracy Temperature Sensor
MCP9803T-M/SN		2-Wire High-accuracy Temperature Sensor

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