Overview
The LM135Z, produced by STMicroelectronics, is a precision temperature sensor that operates as a 2-terminal Zener diode. It is directly calibrated in Kelvin (°K) and offers high accuracy and ease of calibration. The sensor's breakdown voltage is directly proportional to the absolute temperature, with a slope of 10 mV/°K. This device is part of the LM135, LM235, and LM335 series, each with different operating temperature ranges.
The LM135Z is calibrated at +25°C and has a typical error of less than 1°C over a 100°C temperature range. It operates within a current range of 450 µA to 5 mA, with a dynamic impedance of less than 1 Ω, ensuring minimal change in performance across this range.
Key Specifications
| Parameter | Unit | Min. | Max. | |
|---|---|---|---|---|
| Operating Temperature Range | °C | -55 | 150 | |
| Storage Temperature Range | °C | -65 | 150 | |
| Operating Current | mA | 0.45 | 1 | 5 |
| Dynamic Impedance (at 1 mA) | Ω | 0.5 | 0.6 | |
| Output Voltage Temperature Drift | mV/°C | 10 | ||
| Initial Accuracy (at 25°C) | °C | 1 | ||
| Non-linearity (at 1 mA) | °C | 0.3 | 1.5 |
Key Features
- Directly Calibrated in °K: The output voltage is directly proportional to the absolute temperature.
- High Accuracy: 1°C initial accuracy and less than 1°C error over a 100°C temperature range when calibrated at 25°C.
- Low Dynamic Impedance: Less than 1 Ω, ensuring minimal impact on the circuit.
- Wide Operating Current Range: Operates from 450 µA to 5 mA.
- Linear Output: Unlike other sensors, the LM135Z has a linear output voltage versus temperature.
- Easily Calibrated: Single-point calibration corrects errors at all temperatures due to the proportional output to absolute temperature.
Applications
The LM135Z is suitable for a wide range of temperature sensing applications, including:
- Industrial Automation: Temperature monitoring and control in industrial environments.
- Power Supplies: Temperature sensing for power supply units to ensure safe operation.
- Battery Management: Monitoring battery temperatures to optimize performance and safety.
- HVAC Systems: Temperature control in heating, ventilation, and air conditioning systems.
- Appliances: Temperature sensing in various household and commercial appliances.
- Thermocouple Cold Junction Compensation: Compensating for temperature variations in thermocouple measurements.
Q & A
- What is the operating temperature range of the LM135Z?
The LM135Z operates over a temperature range of -55°C to 150°C.
- How accurate is the LM135Z at 25°C calibration?
The LM135Z has a typical error of less than 1°C over a 100°C temperature range when calibrated at 25°C.
- What is the dynamic impedance of the LM135Z?
The dynamic impedance of the LM135Z is less than 1 Ω.
- What is the current range for the LM135Z?
The LM135Z operates within a current range of 450 µA to 5 mA.
- Is the output of the LM135Z linear?
- How is the LM135Z calibrated?
The LM135Z can be calibrated using a single-point calibration method due to its proportional output to absolute temperature.
- What are some common applications of the LM135Z?
The LM135Z is used in industrial automation, power supplies, battery management, HVAC systems, appliances, and thermocouple cold junction compensation.
- What is the storage temperature range for the LM135Z?
The storage temperature range for the LM135Z is -65°C to 150°C.
- Does the LM135Z have any special packaging options?
- How does self-heating affect the accuracy of the LM135Z?
