Diodes Incorporated AP7315-18FS4-7B

Overview

AP7315-18FS4-7B from Diodes Incorporated is a 150mA low-dropout linear regulator with fixed 1.8V output, ±1% accuracy, 75dB PSRR at 1kHz, 60µVrms output noise (10Hz–100kHz), and 35µA quiescent current. It features enable control, operates from 1.7V to 5.25V input, and targets RF supply rails in compact portable devices.

For engineers reviewing the AP7315-18FS4-7B datasheet, AP7315-18FS4-7B pinout, AP7315-18FS4-7B application, or AP7315-18FS4-7B equivalent, key selection criteria include dropout voltage at 150mA (max 0.34V for 1.7V ≤ VOUT < 2.0V), thermal performance in X2-DFN1010-4 package, EN logic thresholds (0.5V low / 1.3V high), and stability with 0.47µF ceramic output capacitance.

Technical Context

The AP7315-18FS4-7B uses a CMOS-based LDO architecture with integrated voltage reference, error amplifier, and current-limit circuitry. Its non-discharge output stage avoids automatic VOUT discharge during shutdown, preserving downstream capacitor charge.

It delivers regulated 1.8V output across –40°C to +85°C ambient, with line regulation of 0.02%/V and load regulation of 0.5%/A. The enable input supports direct logic-level control without external pull-up, and internal short-circuit protection limits output current to ~55mA under VOUT-to-GND fault.

Key Specifications

Pinout & Package

The AP7315-18FS4-7B is housed in a 1.0mm × 1.0mm, 0.4mm pitch X2-DFN1010-4 package with wettable flank leads and an exposed thermal pad. PCB layout requires connection of the thermal pad to GND plane via multiple vias for optimal thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700-1802E/MB and XC6206P182MR-G, the AP7315-18FS4-7B uniquely balances 150mA capability, 75dB PSRR, and 35µA IQ in a 1.0mm² footprint-making it optimal for RF-biased portable systems needing both performance and size efficiency.

Availability

AP7315-18FS4-7B is available at Aetrix Electronics and suitable for RF supply, camera sensor core, wireless adapter SoC I/O, and portable media player audio codec applications requiring stable component supply, consistent parametric performance, and long-term production continuity.

Supply support for AP7315-18FS4-7B 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 power management, signal integrity, and connectivity solutions for industrial, computing, and consumer markets.

The AP7315 series belongs to Diodes' high-PSRR, low-noise LDO product line, engineered specifically for noise-sensitive RF and imaging subsystems in space-constrained portable electronics.

FAQ

What is the minimum input voltage required for AP7315-18FS4-7B to maintain regulation at full 150mA load?

The minimum input voltage is determined by dropout: at 150mA, max dropout is 0.34V for 1.7V ≤ VOUT < 2.0V. With 1.8V output, VIN must be ≥ 2.14V to sustain regulation. Below this, output voltage sags proportionally per load current and temperature.

Can the thermal pad of the X2-DFN1010-4 package be left unconnected?

No. The thermal pad must be soldered to a GND-connected copper pour using ≥4 thermal vias (0.3mm diameter). Leaving it unconnected degrades thermal resistance by >50%, risking junction temperature exceedance above 85°C ambient at full load.

Does AP7315-18FS4-7B include reverse current blocking?

No. The AP7315-18FS4-7B lacks internal reverse-current protection. If VOUT exceeds VIN (e.g., during hot-swap or backup battery scenarios), current flows backward from VOUT to VIN through the pass device. An external Schottky diode is required for reverse-blocking applications.

Is the EN pin internally pulled up or down?

There is no internal pull-up or pull-down on the EN pin. It must be actively driven to ≥1.3V for enable or ≤0.5V for disable. Leaving EN floating causes undefined output state and potential oscillation due to noise coupling, violating absolute maximum ratings.