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Thermistor-to-Digital Converter

Product Details

The MAX6682 converts an external thermistor's temperature-dependent resistance directly into digital form. The thermistor and an external fixed resistor form a voltage-divider that is driven by the MAX6682's internal voltage reference. The MAX6682 measures the voltage across the external resistor and produces a 10-bit + sign output code dependent on that voltage.

The MAX6682 does not linearize the highly nonlinear transfer function of a typical negative temperature coefficient (NTC) thermistor, but it does provide linear output data over limited temperature ranges when used with an external resistor of the correct value. Over the 0°C to +50°C temperature range, the MAX6682 produces output data that is scaled to 8 LSBs/°C (for 0.125°C resolution), provided that the correct thermistor and external resistor values are used. Other temperature ranges can be easily accommodated, but do not necessarily yield data scaled to an even number of LSBs per degree.

The 3-wire SPI™-compatible interface can be readily connected to a variety of microcontrollers.

The MAX6682 is a read-only device, simplifying use in systems where only temperature data is required.

Power-management circuitry reduces the average thermistor current, minimizing self-heating. Between conversions, supply current is reduced to 21µA (typ). The internal voltage reference is shut down between measurements.

The MAX6682 is available in a small, 8-pin µMAX package and is specified over the -55°C to +125°C temperature range.

Key Features

  • Converts Thermistor Temperature to Digital Data
  • Low Average Thermistor Current Minimizes Self-Heating Errors
  • Low Supply Current, 21µA (typ) Including 10kΩ Thermistor Current
  • Internal Voltage Reference Isolates Thermistor from Power-Supply Noise
  • 10-Bit Resolution
  • Accommodates Any Thermistor Temperature Range
  • Output Data Scaled for Direct Temperature Readings from 0°C to +50°C
  • Simple SPI-Compatible Interface
  • Small, 8-Pin µMAX Package
  • Applications/Uses

    • Battery Packs/Chargers
    • Home Appliances
    • HVAC
    • Medical Devices
    Parametric specs for All Temperature Sensors
    Sensor Type Remote
    # Channels One
    Interface 3-Wire/SPI
    Functions Thermistor-to-Digital Converter
    Parasite Pwr. No
    Temp. Resolution (bits) 10
    Oper. Temp. (°C) -55 to +125
    Package/Pins UMAX/8
    Budgetary
    Price (See Notes)
    $2.34 @1k
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    Simplified Block Diagram

    MAX6682: Typical Operating Circuit MAX6682: Typical Operating Circuit Zoom icon

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    Parameters

    Parametric specs for All Temperature Sensors
    Sensor Type Remote
    # Channels One
    Interface 3-Wire/SPI
    Functions Thermistor-to-Digital Converter
    Parasite Pwr. No
    Temp. Resolution (bits) 10
    Oper. Temp. (°C) -55 to +125
    Package/Pins UMAX/8
    Budgetary
    Price (See Notes)
    $2.34 @1k

    Key Features

  • Converts Thermistor Temperature to Digital Data
  • Low Average Thermistor Current Minimizes Self-Heating Errors
  • Low Supply Current, 21µA (typ) Including 10kΩ Thermistor Current
  • Internal Voltage Reference Isolates Thermistor from Power-Supply Noise
  • 10-Bit Resolution
  • Accommodates Any Thermistor Temperature Range
  • Output Data Scaled for Direct Temperature Readings from 0°C to +50°C
  • Simple SPI-Compatible Interface
  • Small, 8-Pin µMAX Package
  • Applications/Uses

    • Battery Packs/Chargers
    • Home Appliances
    • HVAC
    • Medical Devices

    Description

    The MAX6682 converts an external thermistor's temperature-dependent resistance directly into digital form. The thermistor and an external fixed resistor form a voltage-divider that is driven by the MAX6682's internal voltage reference. The MAX6682 measures the voltage across the external resistor and produces a 10-bit + sign output code dependent on that voltage.

    The MAX6682 does not linearize the highly nonlinear transfer function of a typical negative temperature coefficient (NTC) thermistor, but it does provide linear output data over limited temperature ranges when used with an external resistor of the correct value. Over the 0°C to +50°C temperature range, the MAX6682 produces output data that is scaled to 8 LSBs/°C (for 0.125°C resolution), provided that the correct thermistor and external resistor values are used. Other temperature ranges can be easily accommodated, but do not necessarily yield data scaled to an even number of LSBs per degree.

    The 3-wire SPI™-compatible interface can be readily connected to a variety of microcontrollers.

    The MAX6682 is a read-only device, simplifying use in systems where only temperature data is required.

    Power-management circuitry reduces the average thermistor current, minimizing self-heating. Between conversions, supply current is reduced to 21µA (typ). The internal voltage reference is shut down between measurements.

    The MAX6682 is available in a small, 8-pin µMAX package and is specified over the -55°C to +125°C temperature range.

    Simplified Block Diagram

    MAX6682: Typical Operating Circuit MAX6682: Typical Operating Circuit Zoom icon

    Technical Docs

    Support & Training

    Search our knowledge base for answers to your technical questions.

    Filtered Search

    Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal.