STMicroelectronics LF50ABPT-TR

Overview

LF50ABPT-TR from STMicroelectronics is a 5.0 V, ±1% tolerance, automotive-grade low-dropout linear regulator in PPAK-5 package with logic-controlled shutdown, 0.4 V dropout at 500 mA, 500 µA typical quiescent current in ON mode, and -40 °C to 125 °C operating junction temperature - used as a local power supply for infotainment microcontrollers in vehicle head units.

For engineers reviewing the LF50ABPT-TR datasheet, LF50ABPT-TR pinout, LF50ABPT-TR application, or LF50ABPT-TR equivalent, key selection criteria include dropout voltage under load, shutdown logic compatibility (TTL), output voltage accuracy over temperature, thermal resistance (R_thJC = 8 °C/W), and AEC-Q100 qualification status.

Technical Context

The LF50ABPT-TR implements a PNP-based LDO architecture with internal current and thermal limiting, enabling stable 500 mA output delivery even with minimal input–output differential. Its 5-pin PPAK configuration integrates a dedicated TTL-compatible inhibit (INH) input (Pin 2) that enables system-level power gating.

It achieves 76 dB supply voltage rejection at 120 Hz and maintains 50 µV RMS output noise (10 Hz–100 kHz) with only a 2.2 µF ceramic output capacitor (ESR 0.1–10 Ω), eliminating need for bulk electrolytics in space-constrained automotive modules.

Key Specifications

Pinout & Package

LF50ABPT-TR is housed in a thermally enhanced PPAK-5 surface-mount package (4.5 × 6.0 mm, 0.95 mm height) with exposed thermal pad electrically connected to GND. The package supports high-power density mounting and automated reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LDL112PU50R and TLE42754G, LF50ABPT-TR uniquely balances 500 mA capability, 0.4 V dropout, TTL-compatible shutdown, and AEC-Q100 Grade 1 in a compact PPAK-5 - making it optimal for cost- and space-constrained automotive subsystems requiring programmable power states.

Availability

LF50ABPT-TR is available at Aetrix Electronics and suitable for automotive infotainment systems, ADAS camera modules, and body control units requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LF50ABPT-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 microcontrollers, power management ICs, sensors, and automotive-grade analog devices.

The LFXX series was developed specifically for automotive power management, targeting AEC-Q100-compliant local regulation in engine control, chassis, and infotainment domains where low dropout, low quiescent current, and robust thermal performance are mandatory.

FAQ

What is the minimum input voltage required for LF50ABPT-TR to regulate 5.0 V at 500 mA?

The minimum input voltage is 5.4 V, derived from the maximum dropout voltage of 0.4 V at 500 mA load. This ensures stable regulation during automotive cold-crank conditions where battery voltage may dip to 6.0 V - allowing margin for line drop and ripple. Operation below 5.4 V results in unregulated output.

Is the INH pin of LF50ABPT-TR compatible with 3.3 V logic microcontrollers?

Yes - the INH pin accepts TTL-compatible logic levels: V_IL ≤ 0.8 V (OFF) and V_IH ≥ 2.0 V (ON). A 3.3 V GPIO can directly drive it without level shifting, as 3.3 V exceeds the 2.0 V high-threshold requirement and provides sufficient noise margin across -40 °C to 125 °C.

Can LF50ABPT-TR replace LF50ABV50TR in the same PCB layout?

No - LF50ABV50TR uses a DPAK-3 package (no INH pin, fixed-ON operation), while LF50ABPT-TR is PPAK-5 with an additional INH pin and different pinout. The footprints are incompatible, and the TAB connection differs electrically (DPAK TAB = OUT, PPAK TAB = GND). Layout redesign is required.

Does LF50ABPT-TR require an input capacitor, and if so, what value and type?

Yes - a 0.1 µF X7R ceramic capacitor is required between IN and GND, placed within 5 mm of the device. This stabilizes the internal reference and improves transient response. Larger values (>1 µF) are unnecessary and may degrade startup behavior; aluminum or tantalum types are not recommended due to ESR and aging effects.