MCP1703T-3302E/CB 3.3V LDO Voltage Regulator: Technical Specifications and Application Circuit Design

The MCP1703T-3302E/CB from Microchip Technology is a highly efficient, low quiescent current CMOS low-dropout (LDO) voltage regulator designed for a wide range of portable and battery-powered applications. This device provides a fixed 3.3V output from an input voltage range of 2.7V to 16V, making it exceptionally versatile for systems powered by multi-cell batteries, wall adapters, or other unregulated sources.

A key feature of this LDO is its remarkably low quiescent current, which is typically just 2.0 µA. This characteristic is crucial for maximizing battery life in always-on applications, as the regulator consumes very little current itself when providing a small load. Furthermore, it offers a very low dropout voltage—typically 178 mV at 250 mA load—ensuring stable operation even as the input voltage dips close to the output level, thus preserving valuable energy in battery-powered systems.

The MCP1703T-3302E/CB is capable of delivering up to 250 mA of continuous output current with a typical accuracy of ±0.4%. It includes essential built-in protection features such as current limit and thermal shutdown, safeguarding both the regulator and the load under fault conditions. The device is offered in a compact SOT-23-3 surface-mount package, ideal for space-constrained PCB designs.

Application Circuit Design

A typical application circuit for generating a stable 3.3V rail is straightforward, emphasizing the simplicity of use of LDO regulators. The basic design requires only two external components:

1. Input Capacitor (C_IN): A 1 µF ceramic capacitor placed between the input pin (VIN) and ground (GND) is recommended to improve transient response and stability. It should be located as close as possible to the regulator pins.

2. Output Capacitor (C_OUT): A 1 µF ceramic capacitor placed between the output pin (VOUT) and ground (GND) is required for stability. Larger values can be used to improve transient response.

The basic schematic is as follows:

Input Voltage (e.g., 4.0V to 5.5V) → C_IN (1µF) → VIN Pin (MCP1703T-3302E/CB) → VOUT Pin → C_OUT (1µF) → Load (3.3V, up to 250mA)

The GND pin is connected directly to the system ground plane.

This simple design provides a clean, stable voltage source for microcontrollers, sensors, memory chips, and other digital or analog circuits requiring a 3.3V supply.

ICGOODFIND: The MCP1703T-3302E/CB stands out as an optimal choice for power-sensitive designs due to its ultra-low quiescent current, low dropout voltage, and robust performance. Its minimal external component count and integrated protection make it a reliable and efficient solution for extending battery life in portable electronics, IoT devices, and other 3.3V applications.

Keywords: Low Quiescent Current, LDO Voltage Regulator, 3.3V Output, Battery-Powered Applications, Thermal Shutdown Protection.