STMicroelectronics LE45ABZ

Overview

LE45ABZ from STMicroelectronics is a very low dropout (LDO) linear voltage regulator delivering 4.5 V ±1% output at up to 100 mA, with 0.2 V typical dropout at full load, 50 µA quiescent current in OFF mode, and TTL-compatible inhibit control. It operates across –40 °C to 125 °C and supports stable regulation with only a 2.2 µF output capacitor - ideal for space-constrained, battery-powered microcontroller subsystems requiring precise local power.

For engineers reviewing the LE45ABZ datasheet, LE45ABZ pinout, LE45ABZ application, or LE45ABZ equivalent, key selection criteria include dropout voltage under 100 mA load, shutdown logic compatibility, ±1% output accuracy over temperature, thermal performance in SO-8, and stability with low-ESR ceramic capacitors.

Technical Context

This LDO integrates internal current and thermal limiting, uses a precision bandgap reference and error amplifier for tight output regulation, and features an active-low inhibit input (pin 5 in SO-8) that places the device in ultra-low-power OFF mode (<100 µA total supply current). The architecture avoids external compensation and enables fast transient response due to low output impedance.

The SO-8 package employs internally connected pins 2, 3, 6, and 7 to the die attach flag for enhanced thermal dissipation (R_thJA = 55 °C/W), while the TO-92 variant operates continuously without inhibit control. Both versions maintain identical electrical specs except for shutdown functionality.

Key Specifications

Pinout & Package

LE45ABZ is available in SO-8 (surface-mount) and TO-92 (through-hole) packages. The SO-8 variant includes an inhibit function on pin 5; the TO-92 version has no inhibit and operates permanently enabled.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with LDL114M45R and TLV70745PDQNR, LE45ABZ trades higher dropout and lower current capability for integrated inhibit control, proven SO-8 thermal performance, and guaranteed ±1% accuracy over full automotive temperature range - making it optimal for safety-critical, thermally demanding, or power-sequenced designs.

Availability

LE45ABZ is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor nodes, medical wearables, and smart energy metering requiring stable component supply across extended temperature and long product lifecycles.

Supply support for LE45ABZ 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, designing and manufacturing analog, microcontroller, power, and sensing solutions for industrial, automotive, and consumer markets.

The LE series LDOs were developed specifically for low-power, high-reliability embedded systems requiring precision regulation, wide temperature operation, and simple integration - especially where battery life, thermal constraints, and functional safety are design priorities.

FAQ

What is the minimum input voltage required for LE45ABZ to maintain regulation at 100 mA?

The minimum input voltage is calculated as V_OUT + V_DROP = 4.5 V + 0.4 V (max dropout at 100 mA and –40 to 125 °C) = 4.9 V. At room temperature, 4.7 V suffices due to 0.2 V typical dropout. Input must remain below 18 V absolute maximum rating.

Can LE45ABZ be used without the inhibit pin in SO-8 configuration?

Yes - if inhibit functionality is unused, pin 5 must be tied to V_IN (to enable) or grounded (to disable), not left floating. Floating may cause erratic behavior due to noise susceptibility; grounding is preferred for default OFF state in safety-critical systems.

Is the 2.2 µF output capacitor requirement dependent on ESR?

Yes - the 2.2 µF value assumes capacitor ESR between 0.1 Ω and 10 Ω. Ceramic capacitors meeting this ESR range (e.g., X7R 2.2 µF, 10 V) ensure stability without additional series resistance. Lower-ESR types (e.g., C0G) may require a small series resistor to meet phase-margin requirements.

How does thermal performance differ between SO-8 and TO-92 packages?

SO-8 has R_thJA = 55 °C/W (with copper pour) versus TO-92's 200 °C/W. At 100 mA and 1 V dropout (100 mW dissipation), SO-8 rises ~5.5 °C above ambient, while TO-92 rises ~20 °C - making SO-8 suitable for high-density or high-ambient designs where TO-92 would require derating or airflow.