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Key Features
Applications/Uses
Parametric specs for Temperature Sensors
| Sensor Type | Remote |
| # Channels | Four |
| Interface | PWM |
| Functions | Thermistor-to-Digital Converter |
| Accuracy (±°C) | 1 |
| Parasite Pwr. | No |
| Oper. Temp. (°C) | -55 to +125 |
| Package/Pins | UMAX/10 |
| Budgetary Price (See Notes) | 4.31 |
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Simplified Block Diagram
Technical Docs
| Data Sheet | Four-Channel Thermistor Temperature-to-Pulse-Width Converter | Feb 19, 2007 | |
| App Note | Selecting Temperature Sensors for System Measurement and Protection | ||
| Tutorial | Thermal Management Handbook |
Choosing the Best Type of Temperature Sensor
Support & Training
Search our knowledge base for answers to your technical questions.
Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .
Parameters
Parametric specs for Temperature Sensors
| Sensor Type | Remote |
| # Channels | Four |
| Interface | PWM |
| Functions | Thermistor-to-Digital Converter |
| Accuracy (±°C) | 1 |
| Parasite Pwr. | No |
| Oper. Temp. (°C) | -55 to +125 |
| Package/Pins | UMAX/10 |
| Budgetary Price (See Notes) | 4.31 |
Key Features
- Simple Single-Wire Interface
- Measures Up to Four Thermistor Temperatures
- Low-Average Thermistor Current Minimizes Self-Heating Errors
- Internal Voltage Reference Isolates Thermistor from Power-Supply Noise
- Accommodates Any Thermistor Temperature Range
Applications/Uses
- Home Appliances
- HVAC
- Medical Devices
Description
The MAX6691 four-channel thermistor temperature-to-pulse-width converter measures the temperatures of up to four thermistors and converts them to a series of output pulses whose widths are related to the thermistors' temperatures. Each of the four thermistors and an external fixed resistor (REXT) form a voltage-divider that is driven by the MAX6691's internal voltage reference (VREF). VREF and the voltage across REXT are measured and converted to a pulse.
The MAX6691 has a single open-drain I/O pin that can be readily connected to a variety of microcontrollers. The microcontroller initiates a conversion by pulling the I/O pin low and releasing it. When conversion is done, the MAX6691 signals the end of conversion by pulling the I/O pin low once again. The pulse corresponding to the first thermistor is sent immediately after the release of the I/O pin.
The on-chip power-management circuitry reduces the average thermistor current to minimize errors due to thermistor self-heating. Between conversions, the MAX6691 falls into a 10µA (max) sleep mode, where the voltage reference is disabled and the supply current is at its minimum.
The MAX6691 is available in a 10-pin µMAX package and is specified from -55°C to +125°C temperature range.
The MAX6691 has a single open-drain I/O pin that can be readily connected to a variety of microcontrollers. The microcontroller initiates a conversion by pulling the I/O pin low and releasing it. When conversion is done, the MAX6691 signals the end of conversion by pulling the I/O pin low once again. The pulse corresponding to the first thermistor is sent immediately after the release of the I/O pin.
The on-chip power-management circuitry reduces the average thermistor current to minimize errors due to thermistor self-heating. Between conversions, the MAX6691 falls into a 10µA (max) sleep mode, where the voltage reference is disabled and the supply current is at its minimum.
The MAX6691 is available in a 10-pin µMAX package and is specified from -55°C to +125°C temperature range.
Technical Docs
| Data Sheet | Four-Channel Thermistor Temperature-to-Pulse-Width Converter | Feb 19, 2007 | |
| App Note | Selecting Temperature Sensors for System Measurement and Protection | ||
| Tutorial | Thermal Management Handbook |
Support & Training
Search our knowledge base for answers to your technical questions.
Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .
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