STMicroelectronics LE33ABZ

Overview

LE33ABZ from STMicroelectronics is a 3.3 V fixed-output, very low dropout (0.2 V typ. at 100 mA) linear voltage regulator in TO-92 package, featuring TTL-compatible inhibit control, ±1% output voltage accuracy at 25 °C, 80 dB supply voltage rejection at 120 Hz, and operation across –40 to 125 °C. It delivers up to 100 mA output current with only 2.2 µF output capacitance for stability and draws just 50 µA quiescent current in OFF mode - ideal for battery-powered microcontroller subsystems requiring precise, low-noise local regulation.

For engineers reviewing the LE33ABZ datasheet, LE33ABZ pinout, LE33ABZ application, or LE33ABZ equivalent, key selection considerations include its 0.2 V dropout at full load, 50 µA shutdown current, ±1% initial accuracy, SO-8/TO-92 dual-package compatibility, and direct pin-to-pin replacement capability with legacy L78L33 series regulators in space-constrained designs.

Technical Context

The LE33ABZ integrates an internal current-limit and thermal-shutdown protection circuit, enabling robust operation under overload or fault conditions without external components. Its inhibit function uses TTL-level logic on Pin 1 (INH), allowing system-level power sequencing and board-level standby control.

Unlike standard 3-terminal regulators, the TO-92 variant maintains full electrical performance in ON state without enable logic, while the SO-8 version adds active shutdown via the INH pin - supporting dynamic power management in multi-rail embedded systems where selective rail disable reduces total system quiescent consumption.

Key Specifications

Pinout & Package

LE33ABZ is supplied in TO-92 package (3-pin, through-hole), with pin 1 = V_OUT, pin 2 = GND, pin 3 = V_IN. The device does not feature an inhibit pin in TO-92 configuration; inhibit functionality is exclusive to the SO-8 variant (Pin 5). This TO-92 variant operates continuously in ON state.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout linear regulator applications.

Compared with LDL1133PU33R, LE33ABZ offers proven TO-92 reliability and lower BOM cost but trades off current capacity and modern packaging; versus L78L33ACZ, it delivers 110× lower shutdown current and 1.5 V less dropout - critical for battery longevity and low-input-voltage operation.

Availability

LE33ABZ is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body electronics, portable medical monitors, and smart home controller designs requiring stable component supply, long-lifecycle support, and consistent parametric performance across temperature extremes.

Supply support for LE33ABZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and analog products for industrial, automotive, and consumer markets.

The LE series low-dropout regulators were developed to replace legacy 78Lxx parts with enhanced efficiency, tighter accuracy, and extended temperature capability - specifically targeting battery-powered and thermally demanding embedded applications.

FAQ

Is LE33ABZ pin-compatible with L78L33ACZ?

Yes - LE33ABZ uses identical TO-92 pinout (V_OUT-GND-V_IN) and matches L78L33ACZ's mechanical footprint and soldering profile. Electrical upgrades include ±1% vs ±5% output accuracy, 0.2 V vs 1.7 V dropout, and 50 µA vs 5.5 mA quiescent current in shutdown - all without layout changes.

What is the minimum input voltage required for 3.3 V regulation at 100 mA?

The minimum input voltage is 3.5 V, based on the typical 0.2 V dropout voltage at 100 mA load. At worst-case 0.5 V dropout (over temperature), input must be ≥3.8 V to maintain regulation. Input voltage must remain ≤18 V per absolute maximum ratings.

Can LE33ABZ be used with ceramic output capacitors?

Yes - the device is explicitly characterized and stabilized with 2.2 µF ceramic capacitors (ESR 0.1–10 Ω). No series resistor or tantalum capacitor is needed, unlike older regulators. This enables smaller size, lower cost, and improved reliability over electrolytic solutions.

Does LE33ABZ include thermal shutdown and current limiting?

Yes - the datasheet confirms internal thermal shutdown and current limiting functions. These protections activate automatically during overload or excessive junction temperature, preventing damage without external circuitry. Recovery is automatic once fault conditions subside.