Diodes Incorporated AP1117K33L-13

Overview

AP1117K33L-13 from Diodes Incorporated is a 1A low-dropout linear regulator with fixed 3.3V output, TO263-3 package, 1.4V max dropout at 1A, ±2% output voltage accuracy, and integrated thermal shutdown and current limiting. It delivers stable 3.3V supply for high-speed bus termination, VGA card power, and PC peripheral logic rails.

For engineers reviewing the AP1117K33L-13 datasheet, AP1117K33L-13 pinout, AP1117K33L-13 application, or AP1117K33L-13 equivalent, key selection criteria include dropout voltage at full load, thermal resistance (θJC = 3.5°C/W), minimum required output capacitance (4.7µF ceramic), junction temperature range (0°C to +125°C), and TO263 thermal pad layout compliance.

Technical Context

The AP1117K33L-13 implements a bandgap-referenced error amplifier driving an NPN pass transistor, with internal 1.25V reference and fixed-resistor feedback network for 3.3V output. Dropout regulation is maintained down to 1.3V differential (VIN ≥ VOUT + 1.3V) across 0°C–125°C junction temperature.

It features fast transient response (<200µs settling time under 100mA–1A load steps), 70dB ripple rejection at 180Hz, and built-in protection: foldback current limiting (1.1A typical) and thermal shutdown triggered at ~150°C junction temperature.

Key Specifications

Pinout & Package

AP1117K33L-13 uses the TO263-3 (D²PAK) surface-mount package with exposed thermal tab (pin 3). The tab is electrically connected to VOUT and serves as primary heat path to PCB copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LD1117S33TR and TLV1117-33CDR, AP1117K33L-13 offers superior thermal handling (3.5°C/W θJC), higher guaranteed current (1A), and tighter output tolerance (±2%), making it optimal for thermally demanding, high-reliability 3.3V rail generation.

Availability

AP1117K33L-13 is available at Aetrix Electronics and suitable for PC peripheral power, VGA card core supply, and industrial communication modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for AP1117K33L-13 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 semiconductor manufacturer specializing in discrete, analog, and mixed-signal devices, with emphasis on power management, signal integrity, and protection solutions.

The AP1117 series belongs to Diodes' high-reliability linear regulator product line, engineered specifically for stable, low-noise, thermally robust local power delivery in computing, communications, and industrial electronics.

FAQ

What is the minimum input voltage required for AP1117K33L-13 to regulate at full 1A load?

The device requires VIN ≥ VOUT + 1.4V to maintain regulation at 1A, so minimum input is 4.7V. At lower differentials, output voltage drops proportionally per the dropout curve-e.g., at 1.2V differential, output falls to ~3.1V. Input must also stay within absolute max rating (≤18V).

Can AP1117K33L-13 be used with ceramic capacitors only, and what ESR range is acceptable?

Yes-it is explicitly qualified for MLCCs. A minimum 4.7µF X7R ceramic capacitor (ESR ≤0.5Ω) is required on the output. Y5V dielectrics are prohibited due to capacitance drift; aluminum electrolytics require ≥47µF and benefit from parallel 1µF MLCC.

How does the thermal shutdown behavior manifest during overload conditions?

When junction temperature reaches ~150°C, the internal thermal limiter disables the pass transistor, dropping VOUT to near zero. After die cooling by ~20°C, regulation resumes automatically. This hiccup mode prevents permanent damage but causes intermittent output loss during sustained overloads.

Is the TO263 thermal tab electrically isolated, and how should it be connected on the PCB?

No-the tab is internally bonded to VOUT and is not isolated. It must be soldered to a dedicated VOUT copper pour with ≥25 mm² area for thermal conduction. Do not connect it to ground or any other net; incorrect routing risks short-circuit or thermal failure.