L78L18ACUTR

Product Overview

The L78L18ACUTR is a STMicroelectronics linear voltage regulator intended for fixed positive 18 V output at up to 100 mA. The device is supplied in a surface-mount SOT-89-3 package, identified as TO-243AA, and is rated for operation from 0°C to 125°C. Its documented electrical characteristics include a maximum input voltage of 40 V, a 6 mA quiescent current, a maximum supply current of 6.5 mA, and 38 dB PSRR at 120 Hz. Protection features include over current, over temperature, and short circuit. The part is listed with Active lifecycle status.

Key Features

• Fixed positive 18 V output with 100 mA output current rating
• Single regulator channel in a surface-mount SOT-89-3 package
• Maximum input voltage rating of 40 V
• Quiescent current of 6 mA and maximum supply current of 6.5 mA
• Power supply ripple rejection specified as 38 dB at 120 Hz
• Over current, over temperature, and short circuit protection features

Applications

• Regulating a fixed 18 V rail for low-current circuit blocks
• Providing a local surface-mount regulation point where a 100 mA load budget is sufficient
• Using in power distribution circuits that require the listed overcurrent, overtemperature, and short-circuit protections

Design & Procurement Notes

Designers should confirm that the load current remains within the 100 mA output rating and that the input voltage does not exceed the 40 V maximum. The 6 mA quiescent current and 6.5 mA maximum supply current should be included in the power budget, particularly for systems sensitive to static current drain. Because the device is surface-mount SOT-89-3 and rated for 0°C to 125°C, verify board layout, thermal dissipation, and ambient conditions within the final assembly. The fixed 18 V output means the regulator is not adjustable, so system voltage requirements should be checked before selection. The part is listed as Active, and the manufacturer is STMicroelectronics.