Microchip MCP1711T-33I/OT 3V LDO Voltage Regulator: Features and Application Design Guide

The Microchip MCP1711T-33I/OT is a robust, high-performance CMOS low-dropout (LDO) voltage regulator designed to deliver a fixed 3.3V output from input voltages up to 6.0V. This device is particularly engineered for battery-powered and noise-sensitive applications, offering an exceptional blend of low quiescent current, high output accuracy, and outstanding power supply rejection. Its SOT-23-5 package makes it an ideal choice for space-constrained PCB designs.

Key Features and Performance Advantages

A standout feature of the MCP1711T-33I/OT is its remarkably low quiescent current, typically just 2.0 µA. This characteristic is paramount for extending battery life in portable and always-on applications, as the regulator consumes minimal power even when the application is in a standby or sleep mode.

Furthermore, this LDO boasts an impressively low dropout voltage of typically 180 mV at 150 mA load. This allows the regulator to continue providing a stable 3.3V output even as the input voltage source (e.g., a discharging battery) decays to a level very close to the output voltage, maximizing the usable energy from the power source.

The device also features excellent line and load transient response, ensuring a stable output voltage despite fluctuations in the input voltage or changes in the current drawn by the load. This is complemented by a high Power Supply Rejection Ratio (PSRR), which effectively attenuates ripple and noise from the input source, resulting in a clean, stable output crucial for powering sensitive analog and digital circuits like RF modules, sensors, and microcontrollers.

Application Design Guide

Implementing the MCP1711T-33I/OT is straightforward, but following best practices is key to achieving optimal performance.

1. Input and Output Capacitors: For stability and to improve transient response, a 1.0 µF ceramic capacitor on the input and a 1.0 µF ceramic capacitor on the output are recommended. These capacitors should be placed as close as possible to the regulator's pins to minimize parasitic inductance. Using X5R or X7R ceramic capacitors is advised for their stability over temperature and voltage.

2. Thermal Considerations: Although the SOT-23 package has limited thermal dissipation capabilities, it is sufficient for many low-to-medium current applications. The device is protected by an internal thermal shutdown circuit that disables the output when the junction temperature exceeds approximately 150°C. For higher current applications, calculate the power dissipation (P_DISS = (V_IN - V_OUT) I_LOAD) and ensure the junction temperature remains within safe limits. Using generous PCB copper pours connected to the GND pin can act as a heatsink.

3. PCB Layout: A good PCB layout is critical for stability and noise performance. Keep the input and output capacitor loops short and direct. Use a solid ground plane to provide a low-impedance return path and shield against noise.

Typical Applications

This regulator is perfectly suited for a wide range of applications, including:

Battery-Powered Devices: IoT sensors, wearables, remote controls.

Portable Medical Equipment: Hearing aids, glucose meters.

Consumer Electronics: Powering microcontrollers and sensors in smart home devices.

Noise-Sensitive Circuits: Providing clean power to RF transceivers, ADCs, and DACs.

ICGOOODFIND

The MCP1711T-33I/OT stands out as an exceptionally efficient and reliable LDO solution for designers who prioritize ultra-low power consumption, compact size, and clean power delivery. Its combination of microampere-level quiescent current and millivolt-level dropout voltage makes it a superior choice for maximizing battery runtime in modern portable electronics.

Keywords:

1. Low Quiescent Current

2. Low Dropout Voltage (LDO)

3. Power Supply Rejection Ratio (PSRR)

4. Thermal Shutdown Protection

5. Battery-Powered Applications