Overview
The LM335DT, produced by STMicroelectronics, is a precision temperature sensor that operates as a 2-terminal Zener diode. This device is part of the LMx35 series, known for its high accuracy and ease of calibration. The LM335DT is specifically designed to operate within a temperature range of -40°C to 100°C, making it suitable for a variety of applications requiring precise temperature measurement.
The sensor's output voltage is directly proportional to the absolute temperature, with a nominal slope of 10 mV/°K. This linear output simplifies the interface with readout or control circuitry, enhancing its usability in various temperature sensing scenarios.
Key Specifications
| Parameter | Unit | Min. | Typ. | Max. |
|---|---|---|---|---|
| Operating Temperature Range | °C | -40 | - | 100 |
| Operating Output Voltage at Tcase = +25°C, IR = 1mA | V | 2.92 | 2.98 | 3.04 |
| Uncalibrated Temperature Error (IR = 1mA) | °C | - | - | 1.5 |
| Calibrated Error at Extended Temperature (Tcase = Tmax, IR = 1mA) | °C | - | - | 2 |
| Dynamic Impedance (IR = 1mA) | Ω | - | 0.6 | - |
| Operating Current Range | mA | 0.45 | - | 5 |
| Output Voltage Temperature Drift | mV/°C | - | 10 | - |
Key Features
- Directly Calibrated in °K: The output voltage is directly proportional to the absolute temperature at 10 mV/°K.
- High Accuracy: Initial accuracy of 1°C over a 100°C temperature range when calibrated at 25°C.
- Low Dynamic Impedance: Less than 1 Ω, ensuring minimal impact on performance across the operating current range.
- Ease of Calibration: Single-point calibration method allows for higher accuracy by correcting errors at all temperatures.
- Wide Operating Current Range: Operates from 450 µA to 5 mA without significant change in characteristics.
- Linear Output: Unlike other sensors, the LM335DT has a linear output, simplifying interfacing with readout or control circuitry.
- Environmental Compliance: Available in ECOPACK® packages, which meet environmental requirements and are lead-free.
Applications
- Temperature Sensing: Suitable for various temperature sensing applications due to its high accuracy and linear output.
- Power Supplies: Used in power supply units for temperature monitoring and control.
- Battery Management: Employed in battery management systems to monitor temperature conditions.
- HVAC Systems: Utilized in heating, ventilation, and air conditioning systems for precise temperature control.
- Appliances: Integrated into household and industrial appliances for temperature monitoring and control.
- Thermocouple Cold Junction Compensation: Used to compensate for temperature variations in thermocouple measurements.
- Differential Temperature Sensing: Applied in scenarios requiring the measurement of temperature differences.
Q & A
- What is the operating temperature range of the LM335DT?
The LM335DT operates within a temperature range of -40°C to 100°C.
- How is the output voltage of the LM335DT related to temperature?
The output voltage is directly proportional to the absolute temperature at a nominal slope of 10 mV/°K.
- What is the typical initial accuracy of the LM335DT?
The typical initial accuracy is less than 1°C over a 100°C temperature range when calibrated at 25°C.
- What is the dynamic impedance of the LM335DT?
The dynamic impedance is less than 1 Ω.
- What is the operating current range of the LM335DT?
The device operates from 450 µA to 5 mA.
- How can the LM335DT be calibrated for higher accuracy?
The device can be calibrated using a single-point calibration method, which corrects errors at all temperatures.
- What types of packages are available for the LM335DT?
The LM335DT is available in SO-8 packages, among others, and also in ECOPACK® versions for environmental compliance.
- What are some common applications of the LM335DT?
Common applications include temperature sensing, power supplies, battery management, HVAC systems, and appliances.
- How does the LM335DT handle self-heating?
Self-heating can be managed by operating the sensor with a low current and ensuring constant thermal resistance; errors due to self-heating can be externally calibrated.
- What is the significance of the linear output of the LM335DT?
The linear output simplifies the interface with readout or control circuitry, making it easier to integrate into various systems.
