STMicroelectronics LD1117DT50TR

Overview

LD1117DT50TR from STMicroelectronics is a fixed-output 5.0 V, low-dropout linear voltage regulator delivering up to 800 mA output current with 1.0 V typical dropout at 100 mA, ±1 % output voltage tolerance at 25 °C, and 75 dB supply voltage rejection at 120 Hz - used in industrial power rails, embedded microcontroller supply domains, and post-regulation stages after switching converters.

For engineers reviewing the LD1117DT50TR datasheet, LD1117DT50TR pinout, LD1117DT50TR application, or LD1117DT50TR equivalent, this page delivers verified package mapping (SOT-223), confirmed thermal resistance (R_thJA = 110 °C/W), minimum 10 µF stability capacitor requirement, and real-world load regulation performance (≤0.4 % over 10–800 mA) - all critical for LDO selection in space-constrained, thermally sensitive designs.

Technical Context

The LD1117DT50TR employs an NPN pass transistor architecture, enabling high efficiency by routing quiescent current primarily into the load rather than ground - unlike PNP-based regulators. Its internal bandgap reference and error amplifier maintain tight output regulation across line, load, and temperature variations.

It integrates thermal shutdown and current limiting, with guaranteed operation from −40 °C to +125 °C junction temperature. The device requires only a single 10 µF ceramic or tantalum output capacitor for stability and achieves 0.003 % output noise (10 Hz–10 kHz) - making it suitable for noise-sensitive analog and mixed-signal circuits.

Key Specifications

Pinout & Package

LD1117DT50TR is housed in a SOT-223 surface-mount package with exposed thermal pad (TAB) electrically connected to V_OUT. This configuration enables efficient heat transfer to PCB copper while minimizing footprint (6.5 mm × 3.5 mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AMS1117-5.0, LD1117DT50TR offers tighter voltage accuracy and superior thermal performance; versus TLV1117-50, it provides lower output noise at the expense of higher quiescent current - making it optimal for noise-critical industrial power domains.

Availability

LD1117DT50TR is available at Aetrix Electronics and suitable for industrial automation, embedded microcontroller power, and post-regulated dual supply applications requiring stable component supply, long-term manufacturability, and guaranteed parametric consistency across production lots.

Supply support for LD1117DT50TR 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 specializing in power management, microcontrollers, and analog ICs, with manufacturing facilities certified to ISO 9001 and IATF 16949 standards.

The LD1117 series belongs to ST's general-purpose linear regulator product line, designed specifically for cost-effective, robust, and thermally efficient voltage regulation in industrial, consumer, and computing applications.

FAQ

What is the minimum output capacitor required for stability?

The LD1117DT50TR requires a minimum 10 µF output capacitor - ceramic or tantalum - placed as close as possible to the V_OUT and GND pins. Lower values risk oscillation; larger values improve transient response but do not harm stability. ESR should be between 0.1 Ω and 10 Ω for optimal phase margin.

Can LD1117DT50TR replace a 7805 in existing designs?

Yes, LD1117DT50TR is a direct functional replacement for 7805 in SOT-223 footprint designs, offering lower dropout (1.0 V vs. 2.0 V), better accuracy (±1 % vs. ±2 %), and improved PSRR. However, note that its thermal pad is connected to V_OUT, not GND - PCB layout must reflect this difference to avoid short circuits.

What is the maximum allowable input voltage?

The absolute maximum DC input voltage is 15 V per the datasheet. For reliable long-term operation, ST recommends limiting V_IN to ≤12 V when delivering 800 mA, considering power dissipation (P_D = (V_IN − 5 V) × I_OUT) and thermal limits (T_J ≤ 125 °C). At 15 V input and full load, junction temperature exceeds safe limits without significant heatsinking.

Does LD1117DT50TR include reverse-polarity protection?

No, LD1117DT50TR does not integrate reverse-polarity protection. Applying reverse voltage to V_IN relative to GND can cause permanent damage. External protection - such as a series Schottky diode or MOSFET-based ideal diode - must be added if system-level reverse-voltage events are possible.