Diodes Incorporated AP1117Y33L-13

Overview

AP1117Y33L-13 from Diodes Incorporated is a 1A low-dropout linear voltage regulator in fixed 3.3V output mode, housed in SOT89-3 package. It delivers stable 3.3V supply for logic circuits and bus termination with ≤1.4V dropout at full load, supports 4.8V–12V input range, and features built-in thermal shutdown and current limiting. Used in PC peripherals and communication modules where compact size and reliable low-noise regulation are required.

For engineers reviewing the AP1117Y33L-13 datasheet, AP1117Y33L-13 pinout, AP1117Y33L-13 application, or AP1117Y33L-13 equivalent, key selection criteria include dropout voltage at 1A load, thermal resistance (θJA = 164°C/W), output stability with 4.7µF MLCC, fixed 3.3V accuracy (±2%), and SOT89-3 thermal pad layout compatibility.

Technical Context

The AP1117Y33L-13 integrates an internal 1.25V reference, error amplifier, and power transistor to regulate output using feedback from a fixed resistor network. Its dropout behavior is characterized by ≤1.3V at 1A and 125°C junction temperature, enabling operation with minimal VIN–VOUT margin.

It employs internal current limiting and thermal shutdown circuitry that activates at ~150°C junction temperature, with automatic recovery upon cooling. The device requires minimum 4.7µF ceramic or tantalum output capacitance (ESR ≤0.5Ω) placed within 10mm of pins for stability across load transients.

Key Specifications

Pinout & Package

SOT89-3 package with exposed thermal tab connected to VOUT; compact surface-mount footprint (4.5 × 2.5 × 1.5 mm) optimized for space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AMS1117-3.3 and LD1117S33TR, AP1117Y33L-13 offers superior thermal performance in SOT89-3 (164°C/W vs. unavailable/190°C/W), guaranteed 1.4V max dropout at 1A/125°C, and RoHS+Green compliance - making it optimal for space- and reliability-critical 3.3V point-of-load designs.

Availability

AP1117Y33L-13 is available at Aetrix Electronics and suitable for PC peripheral power, communication module supply, VGA card core logic, and consumer equipment interface applications requiring stable component supply, long-term lifecycle continuity, and RoHS-compliant sourcing.

Supply support for AP1117Y33L-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' precision linear regulator product line, designed specifically for low-noise, low-dropout point-of-load regulation in computing, communications, and consumer electronics where compact packaging and thermal robustness are essential.

FAQ

What is the minimum input voltage required for AP1117Y33L-13 to maintain regulation?

The device requires VIN ≥ VOUT + dropout voltage. With 3.3V output and max 1.4V dropout at 1A/125°C, minimum VIN is 4.7V. Datasheet specifies 4.8V minimum for 3.3V fixed version to ensure margin across temperature and load - below this, regulation fails and output drops linearly with input.

Can AP1117Y33L-13 be used with ceramic capacitors only?

Yes - it is explicitly qualified for MLCCs (X7R dielectric, ≥4.7µF, ESR ≤0.5Ω). Unlike older 1117 variants, AP1117 supports low-ESR ceramics without oscillation risk. Avoid Y5V due to capacitance drift; aluminum electrolytics require ≥47µF and benefit from parallel 1µF MLCC.

Is the thermal tab of AP1117Y33L-13 electrically connected, and how should it be handled?

Yes - the exposed thermal tab is internally connected to VOUT (pin 2). It must be soldered to a PCB copper pour tied to the 3.3V output net or a dedicated thermal pad. Do not float or ground the tab; incorrect connection causes regulation failure or thermal runaway.

Does AP1117Y33L-13 include reverse-polarity protection?

No - the device lacks internal reverse-voltage protection. Applying reversed input voltage (VIN < GND) can damage the IC. External protection, such as a series Schottky diode or P-channel MOSFET, is required in systems where input polarity reversal is possible.