Diodes Incorporated AP1118S15L-13

Overview

AP1118S15L-13 from Anachip Corp. is a 1A positive low-dropout linear regulator with fixed 1.5V output, TTL/CMOS-compatible enable function, and guaranteed ≤1.4V dropout at full load. It delivers stable voltage for low-voltage logic supplies in VGA cards and PC peripherals, supporting input voltages up to 18V while maintaining regulation down to VIN = VOUT + 1.3V.

For engineers reviewing the AP1118S15L-13 datasheet, AP1118S15L-13 pinout, AP1118S15L-13 application, or AP1118S15L-13 equivalent, this device is selected for high-speed bus termination, 3.3V/1.5V logic rail generation, and applications requiring fast transient response, thermal shutdown protection, and noise rejection >60dB at 120Hz.

Technical Context

The AP1118S15L-13 employs a PNP pass transistor architecture with internal current limiting and thermal shutdown circuitry. Its enable pin features an internal ~100kΩ pull-down resistor, ensuring default-on operation when left floating or driven low.

It achieves 0.008–0.04%/W thermal regulation and maintains ±1.5% output voltage accuracy over temperature (0°C to 125°C) and load (10mA to 1A), with line regulation of 0.2% across VIN = VOUT+1.5V to 18V.

Key Specifications

Pinout & Package

SOP-8L package: 8-pin surface-mount plastic IC with exposed thermal pad (pin 5 connected to VOUT tab); footprint per JEDEC MS-012, recommended land pattern includes thermal pad soldering for thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP1117-1.5V and LD1117S15TR, AP1118S15L-13 uniquely combines 1A capability, enable control, and SOP-8L thermal pad integration-making it the only option among the three that supports both power sequencing and compact surface-mount thermal management in space-constrained graphics modules.

Availability

AP1118S15L-13 is available at Aetrix Electronics and suitable for VGA graphics card power, PC peripheral interface, CD-ROM drive logic, and industrial bus termination requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for AP1118S15L-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

Anachip Corp. is a Taiwan-based analog and mixed-signal IC designer founded in 1996, specializing in power management, interface, and timing solutions for consumer and industrial markets.

The AP1118 product line targets cost-sensitive, high-volume applications requiring robust LDO performance with integrated protection-specifically designed for PC peripherals, optical drives, and embedded graphics subsystems where reliability and thermal resilience are critical.

FAQ

What is the minimum input voltage required for AP1118S15L-13 to regulate at full 1A load?

The device requires VIN ≥ VOUT + 1.3V to maintain regulation under full load, so minimum input is 2.8V. At 1A, dropout is guaranteed ≤1.4V, meaning 2.9V input ensures stable 1.5V output. Below this threshold, output collapses linearly with input.

Can the EN pin be left unconnected, and what is its default state?

Yes-the EN pin has an internal ~100kΩ pull-down resistor, so it defaults to logic low (enabled) when floating. No external pull-down is needed. Driving it high (>1.6V) disables the output, sinking only 80µA.

Is the exposed thermal pad on SOP-8L electrically connected, and how should it be handled?

Yes-the exposed pad (pin 5) is internally connected to VOUT and serves as the primary thermal path. It must be soldered to a large copper pour tied to the VOUT net; omitting this reduces θ_JA effectiveness and risks thermal shutdown at >0.7A continuous load.

Does AP1118S15L-13 require an input capacitor, and what value is recommended?

While not strictly mandatory, a ≥1µF ceramic capacitor at VIN improves line transient response and prevents oscillation under fast input voltage changes. Datasheet testing used 1µF input + 10µF output (tantalum); for best noise rejection, pair with 10µF X7R ceramic at VIN.