Infineon TLE4250-2G Low-Dropout Voltage Regulator: Features and Application Circuits
The Infineon TLE4250-2G is a monolithic integrated low-dropout voltage regulator designed to deliver a fixed 5V output with a maximum current of up to 250 mA. Renowned for its robustness and precision, it is a cornerstone component in automotive and industrial electronics, where stable voltage rails are critical for microcontrollers, sensors, and other logic circuits.
Key Features and Advantages
The TLE4250-2G stands out due to its suite of features tailored for demanding environments. Its extremely low current consumption of typically 85 µA makes it ideal for battery-powered or always-on applications. A critical feature is its very low dropout voltage, typically 200 mV at Iout = 100 mA, which allows it to continue regulating effectively even when the input voltage dips close to the output level, preserving system functionality.
Beyond basic regulation, the IC incorporates comprehensive protection mechanisms. It features internal current limiting that protects the device and the load during short-circuit events. Furthermore, its overtemperature protection shuts down the regulator if the junction temperature exceeds safe limits, preventing thermal destruction. Another significant advantage is the reverse polarity protection of up to -45V, a vital attribute for automotive applications where load dump or miswiring can occur. The built-in error flag serves as an early warning system, signaling when the output voltage is approximately 10% below its nominal value, often due to a dropout or short-circuit condition.
Typical Application Circuits
The basic application circuit for the TLE4250-2G is remarkably simple, requiring only two external capacitors for stable operation.
1. Standard Regulation Circuit:
The most straightforward configuration involves connecting an input capacitor (C_IN, typically 100 nF) close to the IC's input pin to suppress high-frequency noise. An output capacitor (C_Q, typically 1 µF) is connected to the output pin to ensure stability and improve transient response. The enable pin (EN) can be tied directly to the input voltage (VIN) for always-on operation or driven by a microcontroller for power management.
2. Circuit with Error Flag Monitoring:
For systems requiring diagnostics, the error flag output (Error Flag) is utilized. This open-collector output requires a pull-up resistor to a logic voltage rail (e.g., 5V or 3.3V). Under normal operation, the flag output is high-impedance, pulling the monitored node high via the resistor. When an undervoltage condition is detected, the internal transistor activates, pulling the flag pin to ground and signaling a fault to a microcontroller or other logic circuitry.
3. Enhanced Stability for Demanding Loads:
In scenarios with highly variable loads or particularly long wires on the output, increasing the output capacitor value (e.g., to 2.2 µF or 4.7 µF) or adding a small ceramic capacitor in parallel can further enhance stability and filter noise.
The Infineon TLE4250-2G is an exemplary low-dropout regulator that combines efficiency, robustness, and diagnostic capability. Its minimal external component count, comprehensive built-in protections, and diagnostic error flag make it an exceptionally reliable and cost-effective solution for providing a stable 5V supply in the harsh electrical environments of automotive and industrial systems.
Keywords:
Low-Dropout Regulator, Reverse Polarity Protection, Error Flag, Automotive Grade, Current Limiting
