L78L33ACUTR

Product Overview

The L78L33ACUTR from STMicroelectronics is a linear voltage regulator IC with a single positive fixed output. It provides a regulated 3.3V output from an input voltage with a maximum rating of 30V and has a 100mA output current rating. The device is intended for surface-mount designs and uses a TO-243AA package, also identified as SOT-89-3. Its fixed-output architecture supports compact power rails where a 3.3V supply is required, while the specified operating range of 0°C to 125°C supports use within those limits. Protection features include over-current, over-temperature, and short-circuit protection.

Key Features

• Single positive fixed 3.3V output
• Maximum input voltage: 30V
• Output current: 100mA
• Quiescent current: 5.5 mA; maximum supply current: 6 mA
• PSRR: 49dB at 120Hz
• Integrated protection: over-current, over-temperature, and short-circuit
• Operating temperature range: 0°C to 125°C
• Surface-mount package: TO-243AA (SOT-89-3)

Applications

• Regulating a local 3.3V rail for low-power digital logic in embedded control boards
• Providing a stable supply rail for sensor interfaces and analog front ends
• Supplying low-current peripheral devices from a higher-voltage source

Design & Procurement Notes

When selecting the L78L33ACUTR, verify that the input voltage does not exceed 30V and that load current remains within 100mA. The 5.5 mA quiescent current and 6 mA maximum supply current should be included in the total power budget, especially when the input-to-output voltage difference is large. The 49dB PSRR at 120Hz indicates a defined ripple rejection condition, so supply noise should be considered during system design. The TO-243AA surface-mount package and 0°C to 125°C operating range should be considered for board layout and thermal design. Protection features help guard against over-current, over-temperature, and short-circuit conditions, but the input voltage and load current must still remain within the specified limits.