L78L33ACUTR

Overview

The L78L33ACUTR is a three-terminal positive linear voltage regulator from the STMicroelectronics L78L series, housed in an SOT-89 surface-mount package. It provides a fixed output voltage of 3.3 V with a maximum output current of 100 mA. The device accepts an input voltage range from 5.3 V to 30 V and operates within a junction temperature range of 0 °C to 125 °C. Electrical characteristics include a typical quiescent current of 6 mA at 25 °C, line regulation of 150 mV, load regulation of 60 mV, and a supply voltage rejection ratio of 49 dB at 120 Hz.

Feature Summary

• Internal current limiting and thermal shutdown protection mechanisms ensure robust operation under fault conditions.
• Designed for local or on-card regulation to eliminate noise and distribution issues associated with single-point regulation.
• Functions as a direct replacement for Zener diode and resistor combinations while offering lower quiescent current and reduced noise.
• Requires no external components for basic fixed voltage regulation applications.

Applications

• Local or on-card voltage regulation
• Replacement for Zener diode/resistor networks
• Power pass element integration for high-current regulators

Procurement Notes

Verify that the specific ordering suffix matches the required package type and tape-and-reel specifications. Confirm environmental compliance status such as RoHS designation against project requirements. Ensure the AC accuracy grade aligns with circuit tolerance needs. Cross-reference the manufacturer part number with distributor catalogs to validate authenticity and revision level before finalizing procurement orders.

Selection Notes

Select this component when a fixed 3.3 V output is required with up to 100 mA capability in a compact SMD form factor. The AC suffix indicates tighter voltage accuracy compared to standard variants. Consider the thermal resistance of the SOT-89 package and PCB copper area for adequate heat dissipation. Verify input voltage headroom exceeds the dropout requirement for the intended load current.

Part Context

This device belongs to the L78L series of three-terminal positive regulators manufactured by STMicroelectronics. The series includes multiple fixed output voltage options ranging from 3.3 V to 24 V. These regulators are designed for general-purpose power management tasks where simplicity and reliability are prioritized over low-dropout performance.

Replacement Considerations

Compatible substitutes include other L78L33 variants from different manufacturers, provided they match the SOT-89 pinout and electrical specifications. Verify thermal characteristics and pin configuration compatibility before substitution.