Professional IC Distribution & Technical Solutions

Manufacturer: EXAR

Part Number: SPX1117M3-L-5.0/TR

#### Specifications:

• Output Voltage: 5.0V (Fixed)
• Output Current: Up to 800mA
• Dropout Voltage: 1.2V (Typical at 800mA)
• Input Voltage Range: Up to 15V
• Line Regulation: 0.2% (Typical)
• Load Regulation: 0.4% (Typical)
• Package: SOT-223
• Operating Temperature Range: -40°C to +125°C
• Quiescent Current: 10mA (Typical)
• Protection Features: Thermal Shutdown, Current Limit

#### Descriptions:

The SPX1117M3-L-5.0/TR is a low-dropout (LDO) linear voltage regulator designed to provide a fixed 5.0V output with high accuracy and stability. It is capable of delivering up to 800mA of output current with a low dropout voltage, making it suitable for battery-powered and power-sensitive applications. The device features thermal shutdown and current limit protection for enhanced reliability.

#### Features:

• Fixed 5.0V Output
• Low Dropout Voltage
• High Output Current (800mA)
• Thermal Shutdown Protection
• Current Limiting Protection
• Compact SOT-223 Package
• Wide Operating Temperature Range
• Stable with Low-ESR Capacitors

This regulator is commonly used in consumer electronics, industrial systems, and embedded applications requiring a stable 5V supply.

# Application Scenarios and Design Phase Pitfall Avoidance for SPX1117M3-L-5.0/TR

The SPX1117M3-L-5.0/TR is a low-dropout (LDO) voltage regulator designed to provide a stable 5.0V output with high efficiency and low power dissipation. Its compact SOT-223 package and robust performance make it a popular choice for various electronic applications. However, to maximize its effectiveness, designers must carefully consider its application scenarios and avoid common pitfalls during the design phase.

## Key Application Scenarios

1. Embedded Systems & Microcontrollers

Many microcontroller-based systems (e.g., Arduino, Raspberry Pi, and STM32 boards) require a stable 5V supply. The SPX1117M3-L-5.0/TR is well-suited for such applications, ensuring reliable operation even with fluctuating input voltages.

2. Battery-Powered Devices

Due to its low dropout voltage (typically 1.1V at 800mA), this regulator efficiently steps down higher battery voltages (e.g., 6V–12V) to a steady 5V, extending battery life in portable electronics like IoT sensors and handheld instruments.

3. Industrial Control Systems

In environments with unstable power sources, the SPX1117M3-L-5.0/TR provides noise immunity and stable voltage regulation, making it ideal for PLCs, motor controllers, and automation systems.

4. Consumer Electronics

Devices such as routers, set-top boxes, and USB-powered peripherals benefit from its compact size and ability to maintain a consistent 5V output under varying load conditions.

## Design Phase Pitfall Avoidance

To ensure optimal performance, designers should be mindful of the following challenges:

1. Thermal Management

The SOT-223 package has limited heat dissipation capability. If the regulator operates near its maximum current (800mA) or with a high input-output differential, excessive heat can degrade performance. Proper PCB layout—using a copper pour as a heatsink—is essential.

2. Input/Output Capacitor Selection

The SPX1117M3-L-5.0/TR requires a minimum output capacitance (typically 10µF) for stability. Low-ESR capacitors are recommended to prevent oscillations. Additionally, an input capacitor (1µF or higher) helps suppress input voltage transients.

3. Voltage Drop Considerations

Since the dropout voltage is around 1.1V, the input voltage must always exceed the output voltage by this margin. For a 5V output, the input should not fall below 6.1V under load, or regulation will fail.

4. Load Transient Response

In applications with rapidly changing loads (e.g., switching digital circuits), the regulator may exhibit brief voltage spikes or dips. Adding a larger output capacitor (22µF–47µF) can mitigate this issue.

5. Reverse Polarity & Overvoltage Protection

The SPX1117M3-L-5.0/TR is not inherently protected against reverse voltage or excessive input voltage. Incorporating a diode or transient voltage suppressor (TVS) can safeguard the regulator in harsh conditions.

By addressing these considerations early in the design process, engineers can leverage the SPX1117M3-L-5.0/TR’s strengths while minimizing risks associated with thermal stress, instability, and voltage fluctuations. Careful planning ensures reliable performance across a wide range of electronic systems.