onsemi MC33269DR2-3G 3V LDO Voltage Regulator: Datasheet, Pinout, and Application Circuit Guide
The onsemi MC33269DR2-3G is a robust and reliable low-dropout (LDO) voltage regulator designed to deliver a fixed 3.3V output at a continuous current of up to 800mA. Housed in a space-saving SOIC-8 package, this IC is engineered for a wide range of applications, from consumer electronics to industrial systems, where stable and clean voltage regulation is critical. Its key advantages include very low dropout voltage, minimal power consumption, and integrated protection features, making it an excellent choice for power management solutions.
Datasheet Overview and Key Specifications
A thorough review of the datasheet is essential for proper implementation. The following table summarizes the critical absolute maximum ratings and electrical characteristics of the MC33269DR2-3G.
| Parameter | Symbol | Value | Unit |
| :--- | :--- | :--- | :--- |
| Input Voltage | VIN | 20 | V |
| Output Voltage | VOUT | 3.267 - 3.333 (0°C to 125°C) | V |
| Output Current | IOUT | 800 | mA |
| Dropout Voltage (IOUT = 800mA) | VDO | 1.1 (max) | V |
| Quiescent Current (IQ) | IQ | 7.5 (max) | mA |
| Line Regulation (VIN=5V to 12V) | ΔVOUT/ΔVIN | 5 (max) | mV |
| Load Regulation (IOUT=1mA to 500mA) | ΔVOUT/ΔIOUT | 25 (max) | mV |
| Operating Junction Temperature | TJ | -40 to +150 | °C |
The extremely low dropout voltage of 1.1V maximum at full load ensures efficient operation even as the input voltage approaches the output level, which is vital for battery-powered applications. Furthermore, its built-in current limiting and thermal shutdown protections safeguard the regulator and the load from damage during fault conditions.
Pinout Configuration
The MC33269DR2-3G is offered in an 8-pin SOIC package. The pinout is as follows:
Pin 1 (Input): Supply input voltage. A minimum input capacitor is required for stability.
Pin 2 (Ground): Circuit ground.
Pin 3 (NC): No internal connection. This pin can be left floating.
Pin 4 (Shutdown): Applying a low-level signal (< 0.8V) to this pin disables the output and places the regulator in a low-power standby mode. For normal operation, this pin must be connected to the input (VIN) or driven high.
Pin 5, 6, 7, 8 (Output): These pins are internally connected to form the regulator's output. They must be connected together on the PCB to minimize resistance and improve current handling.
Standard Application Circuit Guide
A typical application circuit for the MC33269DR2-3G is straightforward to implement. The core design requires only two external capacitors for stable operation.
1. Input Capacitor (CIN): A 1µF to 10µF tantalum or aluminum electrolytic capacitor should be placed as close as possible to the input pin (Pin 1) and ground. This capacitor helps to suppress any incoming line transients and provides stable local charge.
2. Output Capacitor (COUT): The regulator requires an output capacitor for frequency compensation and stability. The datasheet recommends a 10µF tantalum capacitor connected between the output (Pins 5-8) and ground. For best performance, this capacitor should also be placed close to the IC. A larger value capacitor can be used to improve the transient response.
3. Shutdown Control: If the shutdown feature is used, a simple logic-level signal from a microcontroller or logic gate can be connected to Pin 4. A pull-up resistor to VIN can be used to ensure default operation if the control signal is not always active.
ICGOODFIND Summary
The onsemi MC33269DR2-3G stands out as a highly efficient and protected 3.3V LDO regulator. Its low dropout voltage and 800mA output current capability make it ideal for demanding applications. The inclusion of critical protection features and an optional shutdown pin for power saving provides designers with a robust and versatile power management solution. Its simple application circuit, requiring minimal external components, allows for quick and reliable integration into various electronic systems.
Keywords: LDO Voltage Regulator, 3.3V Output, Low Dropout Voltage, 800mA, Thermal Shutdown Protection.
