The EZ1117CST-ADJ is an adjustable low dropout (LDO) positive voltage regulator from Semtech. It allows the user to set the output voltage to a desired level using external resistors, making it versatile for various applications requiring different voltage rails.

Applications

• Post Regulation for Switching Power Supplies
• Adjustable Power Supplies
• Battery Chargers
• Microcontroller Power Supplies
• Linear Regulation Applications

Features

• Adjustable Output Voltage (1.25V to 18V)
• Low Dropout Voltage: Typically 1.1V at 800mA
• Output Current: 800mA
• Internal Current Limit
• Thermal Overload Protection
• Available in SOT-223 Package

Benefits

• Flexible Output Voltage Setting
• Efficient Power Conversion
• Protection Against Overcurrent and Overheating
• Compact Size
• Wide Range of Applications

Additional Details

The output voltage of the EZ1117CST-ADJ is set by two external resistors connected as a voltage divider. The output voltage can be calculated using the formula Vout = 1.25V * (1 + R2/R1), where R1 is the resistor between the ADJ pin and ground, and R2 is the resistor between the output and the ADJ pin. The dropout voltage is typically 1.1V at 800mA, enabling efficient regulation even with a small difference between input and output voltages. The internal current limit and thermal shutdown features protect the regulator from damage in overload conditions. The SOT-223 package provides good thermal performance for its size. Careful selection of external components, especially capacitors, is critical for stable operation and optimal transient response. Follow the datasheet recommendations for capacitor values and ESR. The regulator is suitable for a wide range of applications requiring adjustable voltage rails. Proper PCB layout is essential for minimizing noise and ensuring thermal performance.