STMicroelectronics LD1117V50

Overview

LD1117V50 from STMicroelectronics is a fixed-output 5.0 V, low-dropout linear voltage regulator delivering up to 800 mA output current with 1.1 V typical dropout at 800 mA, ±1 % output voltage tolerance at 25 °C, and 75 dB supply voltage rejection at 120 Hz - used in embedded power rails for microcontrollers, sensors, and industrial I/O modules.

For engineers reviewing the LD1117V50 datasheet, LD1117V50 pinout, LD1117V50 application, or LD1117V50 equivalent, this page delivers verified electrical specs, thermal performance data, package-specific layout guidance, and real-world substitution analysis - all grounded in ST's production-grade DocID2572 Rev 38 specification.

Technical Context

The LD1117V50 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 trimming circuitry achieve tight output regulation across temperature and line/load variations.

Stability requires only a 10 µF minimum output capacitor; no input capacitor is mandatory. Thermal shutdown and current limiting are integrated, with junction temperature operation rated from 0 to +125 °C (standard version) or –40 to +125 °C (C-grade variant).

Key Specifications

Pinout & Package

LD1117V50 is available in TO-220, DPAK (TO-252), SOT-223, and SO-8 packages. The tab (exposed pad or metal slug) is electrically connected to V_OUT, serving as both thermal path and output terminal.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM1117MP-5.0/NOPB, LD1117V50 delivers tighter regulation and superior ripple rejection; versus MCP1700T-5002E/MB, it trades ultra-low I_Q for 2.7× higher current capacity and robust thermal design - making it the preferred choice for active 5 V system rails requiring stability under dynamic load.

Availability

LD1117V50 is available at Aetrix Electronics and suitable for industrial control panels, automotive body electronics, medical diagnostics equipment, and point-of-sale terminals requiring stable component supply across long production lifecycles.

Supply support for LD1117V50 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 analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

LD1117V50 belongs to ST's legacy linear regulator product line, engineered for cost-effective, thermally robust, and easy-to-deploy 5 V power conversion in space-constrained and thermally demanding environments.

FAQ

What is the minimum input voltage required for LD1117V50 to maintain regulation at 800 mA?

The minimum input voltage is 6.1 V - calculated as 5.0 V output plus 1.1 V typical dropout voltage at 800 mA. At lower input voltages, the device enters dropout mode and output voltage drops linearly with input. Full regulation is guaranteed only above this threshold under specified thermal conditions.

Can LD1117V50 be used with ceramic output capacitors?

Yes - ST specifies stability with ≥10 µF ceramic, tantalum, or aluminum electrolytic capacitors. Ceramic types are recommended for low ESR and compact layout; ensure capacitance remains ≥10 µF after DC bias derating, especially with X5R/X7R dielectrics.

Does LD1117V50 require an input bypass capacitor?

No input capacitor is mandatory per the datasheet, but ST recommends a 10 µF aluminum or tantalum capacitor close to the IN pin when the input source impedance exceeds 1 Ω or when long traces exist - to prevent oscillation and improve transient response during load steps.

How does thermal performance differ between TO-220 and DPAK packages?

TO-220 has R_thJA = 50 °C/W, while DPAK (TO-252) is rated at 100 °C/W - meaning TO-220 dissipates heat twice as effectively in still air. For 800 mA at 1.1 V dropout (0.88 W dissipation), TO-220 rises ~44 °C above ambient; DPAK rises ~88 °C - necessitating PCB copper pour or forced airflow for DPAK in high-ambient environments.