Infineon TLE4267-2G 5V Low-Drop Voltage Regulator: Features and Application Circuits
The Infineon TLE4267-2G is a monolithic integrated low-drop voltage regulator designed to deliver a fixed, precise 5V output from an input voltage of up to 45V. As a key component in automotive and industrial electronics, it provides the essential function of converting a noisy, unregulated input from the battery or power supply into a clean, stable voltage for sensitive microcontrollers, sensors, and ICs.
Key Features and Advantages
The TLE4267-2G stands out in the crowded linear regulator market due to its robust feature set tailored for harsh environments. Its most notable characteristic is its extremely low dropout voltage, typically 200 mV at a 100 mA load. This allows it to continue regulating the output voltage effectively even when the input voltage dips very close to 5V, which is critical during automotive cranking pulses or other low-voltage scenarios.
Beyond low dropout, the regulator integrates a suite of protection features that ensure system reliability. It includes overtemperature protection, which shuts down the device if the junction temperature exceeds safe limits. Short-circuit protection safeguards both the regulator and the load in the event of an output fault. Furthermore, its reverse polarity protection of up to -45V makes it exceptionally resilient against accidental battery misconnection, a common requirement in automotive applications.
Additional features enhance its usability and performance. An enable input allows for external on/off control, facilitating power management and reducing quiescent current in standby modes. The device also boasts very low quiescent current in operation and features a reset output with a programmable delay. This reset signal provides a defined reset to a downstream microcontroller during power-up, power-down, or during an output dropout event, ensuring a controlled system start-up sequence.
Typical Application Circuits
The basic application circuit for the TLE4267-2G is straightforward, requiring only a few external components for stable operation.
1. Standard Regulation Circuit:
The most common setup involves connecting input and output capacitors. A ceramic or electrolytic capacitor (e.g., 100 nF to 10 µF) should be placed close to the input pin (VI) to smooth incoming power and improve transient response. Similarly, a capacitor on the output pin (VQ) (typically 1 µF or more) is critical for ensuring stability and handling fast load transients. The enable pin (EN) can be tied directly to the input voltage for always-on operation or controlled by a microcontroller GPIO or logic circuit.
2. Circuit with Programmable Reset Delay:
The integrated reset functionality is a key advantage. The reset output pin (RST) is an open-drain output that requires a pull-up resistor, typically to the microcontroller's supply voltage. The delay time between the output voltage reaching a stable 5V and the reset signal going high is set by an external capacitor (Cd) connected to the delay pin (Cd). The value of this capacitor determines the reset delay time, allowing designers to tailor the start-up sequence to the specific requirements of their microcontroller.
3. Handling High Input Voltages and Transients:
In automotive environments, load dump and other transients can cause input voltages to spike significantly. While the TLE4267-2G can handle brief transients, for harsher conditions or sustained high input voltages, a pre-regulator or a simple Zener diode circuit can be added upstream to dissipate excess power and reduce the thermal stress on the regulator itself.
Thermal Management
Due to its linear nature, power is dissipated as heat. The power dissipation is calculated as PD = (VIN - VOUT) ILOAD. For higher input voltages or load currents, this can generate significant heat. Therefore, proper PCB layout with a sufficient copper heatsink area connected to the ground pin (GND) is essential to ensure the internal overtemperature protection does not trigger during normal operation.
The Infineon TLE4267-2G is an exemplary solution for applications demanding a robust, protected, and precise 5V power supply. Its combination of low dropout voltage, comprehensive protection features, and integrated reset generator makes it an ideal choice for automotive body control modules, industrial control systems, and any application where electrical conditions are unpredictable. Its simplicity of use, backed by strong performance, solidifies its position as a go-to component for power management design engineers.
Keywords: Low-Dropout Regulator, Automotive Grade, Reverse Polarity Protection, Reset Generator, Thermal Protection
