MCP1702-3302E/TO 3.3V LDO Voltage Regulator: Features and Application Circuit Design
The MCP1702-3302E/TO is a popular low-dropout (LDO) voltage regulator from Microchip Technology, designed to deliver a fixed 3.3V output from an input voltage source up to 16V. Known for its high efficiency, low quiescent current, and compact packaging, it is widely used in battery-powered and space-constrained applications. This article explores its key features and provides a practical application circuit design guide.
Key Features of the MCP1702-3302E/TO
One of the standout attributes of the MCP1702 is its remarkably low quiescent current, typically just 2µA. This makes it exceptionally suitable for battery-operated devices where power conservation is critical. Additionally, it offers a low dropout voltage of only 178mV at 150mA load, ensuring stable operation even when the input voltage approaches the output level.
The device can deliver up to 250mA of continuous output current with a typical accuracy of ±0.4%. It incorporates built-in protection features such as current limit and thermal shutdown, enhancing system reliability. The TO-92 package is easy to prototype with and is ideal for applications requiring through-hole mounting.
Typical Application Circuit Design
A standard application circuit for the MCP1702-3302E/TO is straightforward, requiring minimal external components. The basic configuration includes input and output capacitors for stability.
The input voltage (VIN), which can range from 3.6V to 16V, is connected to the regulator’s input pin. A 1µF ceramic capacitor (CIN) should be placed between VIN and GND to filter high-frequency noise and ensure input stability. The ground pin is connected directly to the system ground.
The regulated 3.3V output (VOUT) is provided at the output pin. A 1µF ceramic capacitor (COUT) from VOUT to GND is essential for output stability and transient response. While the device is stable with low-ESR ceramic capacitors, the datasheet recommends using capacitors with a value of at least 1µF.
Design Considerations for Stable Operation
For optimal performance, several factors must be considered. Firstly, PCB layout is crucial. Place CIN and COUT as close as possible to the regulator's pins to minimize parasitic inductance and ensure effective decoupling.
Secondly, although the MCP1702 has built-in thermal protection, thermal management is important when operating near its maximum current rating. The TO-92 package has a thermal resistance of approximately 160°C/W. For high current or high ambient temperature applications, ensure adequate airflow or consider using a heatsink to prevent the internal junction temperature from exceeding 125°C.
Finally, for applications with highly noisy or fluctuating input supplies, adding a larger electrolytic capacitor (e.g., 10µF) in parallel with CIN can improve performance and provide better line transient rejection.
The MCP1702-3302E/TO is a highly efficient and reliable LDO regulator, offering an excellent combination of ultra-low quiescent current, low dropout voltage, and robust protection features. Its simple design requirements make it a go-to choice for powering 3.3V subsystems in a vast array of electronic devices, from consumer electronics to industrial sensors.
Keywords:
LDO Voltage Regulator
Low Quiescent Current
3.3V Output
Thermal Shutdown
Application Circuit
