STMicroelectronics LDFPT-TR

Overview

LDFPT-TR from STMicroelectronics is a 1 A adjustable low-dropout linear regulator in DFN6 (3x3) package, operating from 2.6 V to 16 V input and delivering output voltages down to 0.8 V with ±1% precision at 25 °C. It features logic-controlled shutdown (EN), Power Good (PG) open-drain output, 500 mV max dropout at 1 A, and internal thermal/current protection - designed for powering low-voltage microprocessors and memory in space-constrained portable systems.

For engineers reviewing the LDFPT-TR datasheet, LDFPT-TR pinout, LDFPT-TR application, or LDFPT-TR equivalent, key selection criteria include its 0.8 V adjustable output capability, 200 µA typical quiescent current at full load, fast transient response, and dual-package availability (DFN6-2x2/3x3) with exposed thermal pad grounding.

Technical Context

The LDFPT-TR implements an error amplifier-based feedback loop with adjustable reference voltage (0.8 V typ.) and internal pass transistor, enabling precise output regulation across line (2.6–16 V) and load (10 mA–1 A) variations. Its PG pin provides open-drain status signaling referenced to 0.92×V_ADJ (rising) and 0.8×V_ADJ (falling), while EN supports active-high logic control with 0.8 V low threshold and 2 V high threshold.

Thermal management relies on junction-to-ambient R_thJA = 55 °C/W (DFN6-3x3), supported by an exposed GND pad. Stability requires ceramic C_IN ≥ 1 µF and C_OUT ≥ 2.2 µF with ESR in specified range; dropout voltage remains ≤500 mV over –40 °C to 125 °C junction temperature.

Key Specifications

Pinout & Package

Package: DFN6 (3x3 mm, 0.9 mm height) with exposed thermal pad connected to GND. Pin 1–6 arranged in single-row configuration; exposed pad must be soldered to PCB GND plane for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLD1113-33TR and LP5907MFX-3.3/NOPB, LDFPT-TR uniquely combines adjustability, PG signaling, and robust thermal performance in DFN6-3x3 - making it optimal for systems requiring flexible voltage scaling, power sequencing, and 1 A sustained loads.

Availability

LDFPT-TR is available at Aetrix Electronics and suitable for laptop motherboard designs, battery-powered medical sensors, and industrial PLC I/O modules requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for LDFPT-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 products for automotive, industrial, power, and embedded markets with emphasis on energy efficiency and reliability.

LDFPT-TR belongs to ST's LDF family of very low-dropout linear regulators, engineered specifically for high-precision, low-noise power delivery in portable and thermally constrained applications where headroom and quiescent current are critical.

FAQ

What is the minimum input voltage required for LDFPT-TR to regulate 0.8 V output?

The minimum input voltage is 2.6 V per datasheet specification. At 0.8 V output, the device requires sufficient headroom above dropout (≤500 mV at 1 A), so VIN must be ≥1.3 V. However, absolute minimum VIN is fixed at 2.6 V regardless of VOUT - this ensures internal circuitry biasing and reference stability across temperature and process variation.

Can the PG pin drive a microcontroller interrupt directly?

Yes - the PG pin is an open-drain output rated for 6 mA sink current. With a 10–47 kΩ pull-up to a compatible logic rail (e.g., 3.3 V), it delivers clean TTL/CMOS-compatible edges. The rising threshold at 0.92×V_ADJ and falling at 0.8×V_ADJ provide hysteresis to prevent chatter during marginal output conditions.

Is external compensation required for stability with ceramic output capacitors?

No - the LDFPT-TR is internally compensated for use with ceramic capacitors ≥2.2 µF and ESR between 5 mΩ and 100 mΩ. The datasheet's Figure 16 (stability plane) confirms unconditional stability within this range; no series RC network or additional components are needed for standard applications.

How does thermal performance differ between DFN6-2x2 and DFN6-3x3 packages?

DFN6-3x3 offers lower thermal resistance: R_thJA = 55 °C/W vs. 65 °C/W for DFN6-2x2. This translates to ~18% higher power dissipation capability at the same ambient temperature. For 1 A loads near maximum dropout (500 mV), DFN6-3x3 allows ~10 °C lower junction temperature - critical for extended operation in sealed enclosures or high-temperature industrial settings.