STMicroelectronics LF120ABDT-TR

Overview

LF120ABDT-TR from STMicroelectronics is a very low-dropout linear voltage regulator with logic-controlled electronic shutdown, delivering 1.2 V output at up to 500 mA. It features 0.45 V dropout at 200 mA, 50 µA quiescent current in OFF mode, ±1% output voltage accuracy at 25 °C, and AEC-Q100 qualification for automotive use in DPAK package. It serves as a local power rail regulator in engine control units and ADAS domain controllers.

For engineers reviewing the LF120ABDT-TR datasheet, LF120ABDT-TR pinout, LF120ABDT-TR application, or LF120ABDT-TR equivalent, key selection criteria include dropout voltage at full load, shutdown logic compatibility (TTL), thermal performance in DPAK (R_thJA = 100 °C/W), and automotive-grade qualification across –40 °C to 125 °C junction temperature.

Technical Context

The LF120ABDT-TR implements a PNP-based LDO architecture with internal current and thermal limiting, enabling stable operation without external protection circuitry. Its inhibit function accepts TTL-compatible logic signals on Pin 2, allowing precise system-level power sequencing and standby mode activation.

Designed for automotive environments, it supports input voltages from 2.5 V to 16 V and maintains ±1% output accuracy over temperature (–40 °C to 125 °C) and line/load variations. Stability requires only a 2.2 µF ceramic output capacitor with ESR between 0.1 Ω and 10 Ω.

Key Specifications

Pinout & Package

DPAK (TO-252-3) package with exposed thermal pad electrically connected to GND; suitable for automated reflow assembly and high-reliability automotive PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP1117ST12T3G, LF120ABDT-TR adds critical inhibit control and automotive qualification; versus TPS78012QDCYRQ1, it trades ultra-low IQ for superior thermal handling in DPAK-making it optimal for sustained 500 mA automotive loads.

Availability

LF120ABDT-TR is available at Aetrix Electronics and suitable for engine control units, ADAS camera modules, body control modules, and infotainment subsystems requiring stable component supply across automotive production lifecycles.

Supply support for LF120ABDT-TR 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

The LFXX series was developed specifically for automotive power management, targeting low-noise, low-quiescent-current LDO regulation in harsh thermal and electrical environments-enabling compliance with AEC-Q100 and ISO 26262 functional safety requirements.

FAQ

What is the minimum input voltage required for regulation at 500 mA output?

The LF120ABDT-TR requires a minimum input voltage of 1.65 V (1.2 V + 0.45 V dropout) to maintain regulation at 200 mA. At 500 mA, typical dropout rises to 0.7 V per automotive-grade characterization, so minimum input is 1.9 V. Input below this causes output collapse or foldback current limiting.

Can the INH pin be left floating, or does it require a pull-up/down resistor?

The INH pin must not be left floating: it has no internal pull-up or pull-down. For guaranteed ON operation, tie INH to VIN through a 10 kΩ resistor; for guaranteed OFF, connect to GND. Floating may cause erratic enable/disable behavior due to noise susceptibility in automotive EMI environments.

Is the DPAK thermal pad required to be soldered to PCB ground plane?

Yes-the exposed thermal pad on the DPAK package is internally connected to GND and serves as the primary thermal conduction path. It must be soldered to a minimum 100 mm² copper area on the PCB's inner or outer layer, with ≥4 thermal vias (0.3 mm diameter) to internal ground planes to achieve rated R_thJA = 100 °C/W.

Does the ±1% output voltage tolerance apply across the full –40 °C to 125 °C range?

No-the ±1% tolerance (AB grade) is specified at 25 °C only. Over the full automotive temperature range (–40 °C to 125 °C), total output variation is ±2.5% maximum, including line, load, and temperature effects-per Table 6 and Table 8 in the datasheet for automotive-grade variants.