Microchip MCP1801T-3302I/OT 3V LDO Voltage Regulator: Features and Application Circuits
The Microchip MCP1801T-3302I/OT is a high-performance, low-dropout (LDO) linear voltage regulator designed to deliver a fixed 3.3V output from an input voltage range of 2.7V to 6.0V. This device is part of a family of LDOs renowned for their very low quiescent current and low dropout voltage, making them particularly suited for battery-powered and portable applications where extended operational life is critical.
A key feature of the MCP1801 is its remarkably low quiescent current, typically just 56 µA during operation and a mere 100 nA in shutdown mode. This ensures minimal power is drawn from the source when the system is in a standby or sleep state, drastically conserving energy. Furthermore, it offers a low dropout voltage of typically 210 mV at a 150 mA load, allowing it to continue regulating the output voltage effectively even as the input voltage dips very close to the output level. This is especially valuable as battery voltage decays over time.
The regulator integrates essential protection features to enhance system reliability. These include overcurrent protection (OCP) and overtemperature protection (OTP), which safeguard both the IC and the downstream circuitry from damage during fault conditions. With a maximum output current of 150 mA, it is perfectly sized for powering microcontrollers, sensors, and other low-power peripherals.
Typical Application Circuits
The basic application circuit for the MCP1801T-3302I/OT is refreshingly simple, requiring only two external capacitors for stable operation.
1. Standard 3.3V Regulation Circuit:
The most straightforward implementation involves connecting an input capacitor (typically 1 µF) between the input pin (VIN) and ground, and an output capacitor (typically 1 µF) between the output pin (VOUT) and ground. The SHDN (Shutdown) pin can be tied to VIN to enable the output permanently or controlled by a microcontroller's GPIO pin to place the regulator in its ultra-low-power shutdown state. This simple circuit provides a clean, stable 3.3V rail from a higher input voltage source like a 4.2V Li-Ion battery or a 5V USB bus.
2. Battery-Powered Application with Enable Control:
In a wireless sensor node or other battery-operated device, the circuit can be modified to maximize battery life. The input is connected to the battery. The SHDN pin is driven by a microcontroller. When the system needs to take a measurement and transmit data, the MCU enables the regulator. Once the task is complete, the MCU shuts down the regulator, cutting power to all peripherals and reducing the system's total quiescent current to almost nothing, dominated by the LDO's 100 nA shutdown current and the MCU's sleep current.
The MCP1801T-3302I/OT is available in the space-efficient SOT-23-5 package, making it an excellent choice for designs with severe PCB area constraints.
In summary, the MCP1801T-3302I/OT from Microchip is an exceptional LDO regulator that excels in power-sensitive designs. Its standout combination of ultra-low quiescent current, low dropout voltage, and robust protection features makes it a premier choice for developers creating the next generation of portable, battery-powered, and always-on devices.
Keywords:
LDO Regulator
Low Quiescent Current
Battery-Powered Applications
3.3V Output
Low Dropout Voltage
