STMicroelectronics LF50CPT-TR

Overview

LF50CPT-TR from STMicroelectronics is a 5.0 V, ±2% tolerance automotive-grade low-dropout linear regulator in PPAK-5 package, delivering up to 500 mA output current with 0.45 V dropout at 200 mA and 50 µA quiescent current in shutdown mode. It features logic-controlled inhibit (TTL-compatible pin 2), internal thermal/current limiting, and stable operation with only 2.2 µF output capacitance-designed for engine control units and ADAS power rails requiring AEC-Q100 compliance.

For engineers reviewing the LF50CPT-TR datasheet, LF50CPT-TR pinout, LF50CPT-TR application, or LF50CPT-TR equivalent, key selection criteria include its -40 °C to 125 °C junction temperature range, 80 dB supply voltage rejection at 120 Hz, 0.2 V minimum dropout at 200 mA, and PPAK-5 thermal resistance of 8 °C/W (junction-to-case).

Technical Context

The LF50CPT-TR implements a fixed-output, NPN-based LDO architecture with integrated shutdown control via Pin 2 (INH), enabling system-level power gating. Its internal bandgap reference and error amplifier maintain output regulation across input voltages from 6 V to 16 V and load currents from 0 to 500 mA.

Thermal protection activates at junction temperatures exceeding 165 °C, and current limiting engages at ~1 A. The device achieves stability with ceramic output capacitors as low as 2.2 µF (ESR 0.1–10 Ω), eliminating need for electrolytic or tantalum types.

Key Specifications

Pinout & Package

LF50CPT-TR uses the PPAK-5 surface-mount package (7.8 mm × 4.4 mm × 1.8 mm), with exposed thermal pad electrically connected to GND for enhanced heat dissipation. Thermal resistance is R_thJC = 8 °C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV73350PDBVR, LF50CPT-TR provides automotive qualification and higher output current; compared with TPS7B6950QDCYRQ1, it delivers lower dropout and reduced output capacitance requirements-enabling smaller, cooler, and more cost-effective power stages in AEC-Q100-compliant designs.

Availability

LF50CPT-TR is available at Aetrix Electronics and suitable for engine control units, ADAS domain controllers, body control modules, and infotainment systems requiring stable component supply across automotive production lifecycles.

Supply support for LF50CPT-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, specializing in automotive, industrial, and power management ICs with vertical manufacturing capabilities.

The LFXX series was developed specifically for automotive power management, targeting AEC-Q100-compliant LDO applications in harsh environments where low dropout, low noise, and robust protection are mandatory.

FAQ

What is the maximum input voltage for LF50CPT-TR?

The absolute maximum DC input voltage is 40 V, but the device enters shutdown when input exceeds 18 V. For normal regulation, the recommended operating input range is 6 V to 16 V-ensuring stable 5 V output across automotive battery conditions including cold-crank (6.5 V) and load-dump (up to 35 V, requiring external clamping).

Can LF50CPT-TR be used without the INH pin connected?

Yes. Leaving Pin 2 (INH) open or tying it to IN (Pin 1) forces the device into permanent ON mode. However, doing so forfeits shutdown capability and increases quiescent current from 50 µA to 500 µA-making it unsuitable for battery-sensitive applications like key-off ECU memory retention.

Is an input capacitor required for stability?

A 0.1 µF ceramic input capacitor is specified in the datasheet for high-frequency noise filtering and transient response improvement. While the regulator remains stable without it, omitting CI risks degraded line transient performance and potential oscillation during fast input voltage steps-especially in noisy automotive environments.

How does thermal performance compare between PPAK and DPAK packages?

PPAK-5 has R_thJC = 8 °C/W versus DPAK's 10 °C/W, enabling ~25% higher power dissipation before thermal shutdown. Both share identical R_thJA = 100 °C/W, but PPAK's larger thermal pad improves board-level heat spreading when soldered to ≥2 cm² copper area-critical for sustained 500 mA operation at 125 °C ambient.