Overview
The LM431CIM3X is an adjustable precision shunt voltage regulator produced by Texas Instruments. This component is designed to provide high temperature stability across its entire operating range, making it suitable for a variety of applications requiring precise voltage regulation. The LM431 is available in several package options, including the space-saving SOT-23 package, which is ideal for space-critical designs. The device operates by shunting more or less current to ground based on the input voltage and load, and it requires only a small quiescent current for regulation.
Key Specifications
| Parameter | Min | Max | Unit | |
|---|---|---|---|---|
| Cathode Voltage | - | - | 37 | V |
| Continuous Cathode Current | -10 | - | 150 | mA |
| Reference Input Current | - | - | 10 | mA |
| Internal Power Dissipation (SOT-23) | - | - | 0.28 | W |
| Operating Temperature (Industrial) | -40 | - | 85 | °C |
| Operating Temperature (Commercial) | 0 | - | 70 | °C |
| Storage Temperature | -65 | - | 150 | °C |
| Minimum Operating Current | 1 | - | - | mA |
| Maximum Operating Current | - | - | 100 | mA |
| Reference Voltage (VREF) | - | 2.5 | - | V |
| Output Voltage Range | 2.5 | - | 36 | V |
Key Features
- Adjustable Precision Shunt Regulator: The LM431 allows the output voltage to be set at any level greater than 2.5 V up to 36 V using external resistors.
- Temperature Stability: Ensured temperature stability over the entire temperature range of operation with an average temperature coefficient of 50 ppm/°C.
- Low Dynamic Output Impedance: The device has a low dynamic output impedance, making it suitable for applications requiring stable voltage regulation.
- Fast Turn-On Response: The LM431 has fast turn-on characteristics, making it an excellent replacement for many Zener diode applications.
- Low Output Noise: The regulator offers low output noise, which is beneficial in noise-sensitive applications.
- Space-Saving Packages: Available in SOIC-8, SOT-23, and TO-92 packages to meet small footprint requirements.
Applications
- Adjustable Voltage or Current Linear and Switching Power Supplies: The LM431 can be used to regulate voltage or current in various power supply designs.
- Voltage Monitoring: Suitable for voltage monitoring applications due to its precision and stability.
- Current Source and Sink Circuits: Can be used in circuits that require precise current sources or sinks.
- Circuits Requiring Precision References: Ideal for applications needing high precision voltage references.
- Zener Diode Replacements: The LM431 can replace traditional Zener diodes in many applications due to its adjustable output voltage and better temperature stability.
Q & A
- What is the LM431CIM3X used for?
The LM431CIM3X is an adjustable precision shunt voltage regulator used for precise voltage regulation in various applications.
- What are the available package options for the LM431?
The LM431 is available in SOIC-8, SOT-23, and TO-92 packages.
- What is the output voltage range of the LM431?
The output voltage can be set at any level greater than 2.5 V up to 36 V using external resistors.
- What is the minimum and maximum operating current of the LM431?
The minimum operating current is 1 mA, and the maximum operating current is 100 mA.
- How does the LM431 regulate voltage?
The LM431 regulates voltage by shunting more or less current to ground based on the input voltage and load.
- What is the typical thermal hysteresis of the LM431?
The typical thermal hysteresis is defined as the change in 25°C voltage measured after thermal cycling between 0°C and 70°C.
- Is an external capacitor required for the LM431?
No, an external capacitor is not required, but it is recommended to reduce noise on the input voltage line.
- What are some common applications of the LM431?
Common applications include adjustable voltage or current power supplies, voltage monitoring, current source and sink circuits, and precision reference circuits.
- How do I select the series resistor (R_S) for the LM431?
R_S must be selected such that it supplies at least the minimum acceptable current to the LM431 and does not exceed the maximum current of 100 mA under all operating conditions.
- What are the ESD protection considerations for the LM431?
The LM431 has limited built-in ESD protection, so it is recommended to short the leads together or place the device in conductive foam during storage or handling.
