L78L12ACUTR

Product Overview

The L78L12ACUTR from STMicroelectronics is a positive fixed-output linear voltage regulator for surface-mount power regulation tasks. It provides a single regulated 12 V output at up to 100 mA, with an input voltage limit of 35 V. The device operates from 0°C to 125°C and uses a TO-243AA (SOT-89-3) package. Its electrical characteristics include 6 mA quiescent current, a 6.5 mA maximum supply current, and 42 dB power-supply rejection at 120 Hz.

Key Features

• Positive fixed 12 V output
• Single regulator channel delivering up to 100 mA
• Input voltage rating up to 35 V
• Quiescent current of 6 mA and maximum supply current of 6.5 mA
• 42 dB power-supply rejection at 120 Hz
• Protection against overcurrent, overtemperature, and short-circuit conditions
• Operating temperature range of 0°C to 125°C
• Surface-mount TO-243AA package, SOT-89-3 footprint

Applications

• Fixed 12 V regulation for low-current logic and interface circuits
• Auxiliary 12 V supply for sensor and measurement front-end boards
• Regulated 12 V rail on compact embedded control boards
• 12 V supply stabilization for small communication modules and transceiver boards
• Maintaining a fixed 12 V output for low-power subsystems

Design & Procurement Notes

When selecting this regulator, confirm that the input voltage does not exceed 35 V and that the load current does not exceed 100 mA. Because linear regulation dissipates power based on the input-output voltage differential and output current, board layout and ambient temperature should support operation across the 0°C to 125°C range. The SOT-89-3 surface-mount footprint requires pad and thermal relief planning. The 42 dB PSRR at 120 Hz may be useful for supply-noise rejection at that frequency, while sensitive analog stages may still need additional filtering. The overcurrent, overtemperature, and short-circuit protections can improve fault resilience, but system-level protection should still be reviewed.