onsemi NCP1117DT33RKG 3V LDO Voltage Regulator: Datasheet, Application Circuit, and Pinout Guide

The onsemi NCP1117DT33RKG is a popular low-dropout (LDO) voltage regulator from a renowned semiconductor manufacturer, designed to provide a fixed, highly stable 3.3V output from a higher input voltage. As a critical component in countless electronic designs, it offers a reliable and cost-effective solution for power management, ensuring sensitive circuits receive clean, regulated power.

This device is part of the NCP1117 series, which is known for its robustness and performance. The "DT" in its part number signifies the DPAK surface-mount package, offering an excellent balance of power dissipation capability and board space efficiency. The regulator features a low 1.2V dropout voltage at maximum current, meaning it can continue to regulate the output voltage even when the input is as low as ~4.5V, making it highly efficient, especially in battery-powered applications where the input voltage decays over time. With an output current capability of up to 1A, it is suitable for powering a wide range of loads, including microcontrollers, sensors, and other digital ICs.

Key Features and Datasheet Overview

Consulting the official datasheet is essential for any design. Key specifications include:

Output Voltage: Fixed 3.3V (Other variants available for adjustable, 1.5V, 1.8V, 2.5V, 5.0V)

Output Current: Up to 1A

Dropout Voltage: 1.2V @ 1A (max)

Line Regulation: 0.2% (typ)

Load Regulation: 0.4% (typ)

Package: DPAK (TO-252)

Protection Features: Internal current limiting and thermal shutdown for robust overcurrent and overtemperature protection.

Pinout Guide

The NCP1117DT33RKG in the DPAK package has three pins/pads:

1. Pin 1 (Adjust/Ground): For fixed-voltage versions like the DT33, this pin is connected to Ground (GND).

2. Pin 2 (Output): This is the regulated 3.3V output (Vout). A capacitor must be connected here for stability.

3. Pin 3 (Input): This is the input voltage (Vin) supply pin, which must be higher than Vout + Dropout Voltage.

Application Circuit

The typical application circuit for this fixed 3.3V LDO is straightforward, requiring only two capacitors for stable operation, as recommended in the datasheet.

Input Capacitor (C_IN): A 10µF tantalum or aluminum electrolytic capacitor should be placed between the input pin and ground. This capacitor helps to smooth any input voltage ripple and is crucial for stability, especially when the regulator is located far from the primary power source.

Output Capacitor (C_OUT): A 22µF tantalum capacitor is recommended on the output pin to ground. This capacitor is critical for maintaining stability and ensuring a good transient response to sudden changes in the load current. While tantalum types are specified, low-ESR ceramic capacitors can often be used with careful consideration, though the datasheet should be consulted for stability requirements.

ICGOODFIND Summary

The onsemi NCP1117DT33RKG is a highly reliable and industry-standard 3.3V LDO regulator, prized for its simplicity, robust 1A output capability, and built-in protection features. Its low dropout voltage makes it exceptionally useful in applications where the input-to-output voltage differential is small. The simple two-capacitor application circuit allows for easy and fast implementation, solidifying its role as a fundamental building block in power supply design for a vast array of electronic devices, from consumer gadgets to industrial equipment.

Keywords: LDO Voltage Regulator, 3.3V Output, 1A Output Current, Thermal Shutdown, DPAK Package.