Diodes Incorporated AP1117E50G-U

Overview

AP1117E50G-U from Diodes Incorporated is a 1A low-dropout linear regulator in fixed 5.0V output mode, housed in SOT223 package. It delivers stable 5.0V supply with ≤1.4V dropout at full load, supports 6.4–18V input range, and features built-in thermal shutdown and current limiting - deployed in PC peripherals, VGA cards, and 3.3V/5V logic power rails.

For engineers reviewing the AP1117E50G-U datasheet, AP1117E50G-U pinout, AP1117E50G-U application, or AP1117E50G-U equivalent, key selection criteria include dropout voltage at 1A load, thermal resistance (θJA = 107°C/W), output stability with 4.7µF MLCC, junction temperature range (0°C to +125°C), and SOT223 thermal pad layout compliance.

Technical Context

The AP1117E50G-U implements a bandgap-referenced error amplifier driving a PNP pass transistor, enabling fast transient response and <1% load regulation across 0–1A. Its internal 1.25V reference and fixed resistor network set VOUT = 5.00V ±1% at 10mA, with line regulation ≤0.2% over VIN = 6.5–12V.

Thermal protection activates at ~150°C junction temperature, cycling output off/on during overload; quiescent current is 5–10mA minimum load requirement. Stability is ensured with output capacitor ESR between 0.15Ω and 0.5Ω, compatible with X7R MLCCs (not Y5V).

Key Specifications

Pinout & Package

SOT223 package with exposed thermal tab electrically connected to VOUT; 3-pin configuration optimized for surface-mount thermal dissipation on PCB copper pours.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1117E50G-U, AP1117E33G-U offers identical thermal and transient performance at 3.3V, while TLV1117-50CDCYR provides lower dropout and higher accuracy at the cost of reduced current guarantee and higher IQ - guiding selection based on input headroom and precision needs.

Availability

AP1117E50G-U is available at Aetrix Electronics and suitable for PC peripheral power, VGA card logic supply, and industrial communication modules requiring stable component supply with lead-free compliance and SOT223 thermal management.

Supply support for AP1117E50G-U 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management and signal integrity solutions for industrial, computing, and consumer markets.

The AP1117 series targets cost-sensitive, thermally constrained applications needing robust 1A LDOs with extended temperature capability and MLCC compatibility - bridging legacy '1117 functionality with improved stability and green packaging.

FAQ

What is the minimum input voltage required for AP1117E50G-U to regulate at 5.0V?

The AP1117E50G-U requires a minimum input voltage of 6.4V to maintain regulation at 5.0V output under full 1A load, based on its guaranteed 1.4V maximum dropout voltage. At lighter loads, VIN may be reduced further - e.g., 6.2V suffices at 500mA - but 6.4V ensures specification compliance across temperature and process variation.

Can AP1117E50G-U operate with a 4.7µF X5R ceramic capacitor on the output?

Yes, AP1117E50G-U is explicitly qualified for stability with 4.7µF X7R MLCCs; X5R is acceptable if ESR remains within 0.15–0.5Ω and capacitance does not fall below 3.5µF at bias. Avoid Y5V due to excessive capacitance loss under DC bias, which risks instability and oscillation.

Is thermal pad connection mandatory for AP1117E50G-U in SOT223?

Yes - the exposed thermal tab (pin 2/VOUT) must be soldered to a ≥5mm×5mm copper pour on the PCB to achieve the specified θJA = 107°C/W. Omitting this connection raises thermal resistance significantly, risking thermal shutdown at currents well below 1A, especially in still-air environments.

Does AP1117E50G-U require an input capacitor, and what value is recommended?

Yes - a minimum 4.7µF input capacitor with ESR ≤0.5Ω is required for stability and transient response. Ceramic or solid tantalum types are preferred; aluminum electrolytic is acceptable only if ≥47µF and paralleled with a 1µF MLCC to ensure low impedance at high frequencies.