Diodes Incorporated AP7315D-285FS4-7B

Overview

AP7315D-285FS4-7B from Diodes Incorporated is a 2.85V fixed-output, 150mA low-dropout linear regulator with high PSRR (75dB at 1kHz), ultra-low output noise (60µV_rms, 10Hz–100kHz), ±1% output voltage accuracy, and enable-controlled shutdown. It features CMOS-based architecture, 35µA quiescent current, and operates from 1.7V to 5.25V input - optimized for RF supply rails in compact portable devices.

For engineers reviewing the AP7315D-285FS4-7B datasheet, AP7315D-285FS4-7B pinout, AP7315D-285FS4-7B application, or AP7315D-285FS4-7B equivalent, key selection criteria include dropout voltage at 150mA (210mV typical), thermal performance in X2-DFN1010-4, EN logic thresholds (0.5V low / 1.3V high), and discharge functionality for fast VOUT decay during shutdown.

Technical Context

The AP7315D variant integrates an internal NMOS pass transistor with auto-discharge circuitry that actively pulls VOUT to GND when EN is low, eliminating external discharge resistors. Its error amplifier uses a precision bandgap reference and achieves ±30ppm/°C temperature coefficient over –40°C to +85°C.

Designed for noise-sensitive analog and RF subsystems, it maintains stability with 0.47µF ceramic CIN/COUT and delivers 75dB ripple rejection up to 10kHz. The device employs fold-back current limiting (55mA short-circuit clamp) and thermal shutdown protection, with power dissipation limited to 400mW on JEDEC High-K board.

Key Specifications

Pinout & Package

X2-DFN1010-4 (1.0mm × 1.0mm, 0.4mm pitch) package with exposed thermal pad; requires PCB copper pour connected to GND for optimal thermal dissipation (θ_JA ≈ 220°C/W on 2-layer JEDEC board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-285E/TT and XC6219B285MR-G, the AP7315D-285FS4-7B uniquely balances 35µA IQ, 210mV dropout, and integrated discharge in a 1.0mm² DFN - making it optimal for space-constrained, noise-sensitive, and fast-sequencing designs.

Availability

AP7315D-285FS4-7B is available at Aetrix Electronics and suitable for RF power amplifier bias, camera module core supply, and wireless audio codec supply requiring stable component supply, tight voltage tolerance, and low-noise regulation.

Supply support for AP7315D-285FS4-7B 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 semiconductor company specializing in discrete, analog, and mixed-signal solutions for power management, signal integrity, and connectivity applications.

The AP7315 series belongs to Diodes' high-PSRR, low-noise LDO product line, engineered specifically for noise-critical portable electronics including smartphones, wearables, and wireless infrastructure.

FAQ

What is the purpose of the thermal pad on the X2-DFN1010-4 package?

The thermal pad is a non-electrical feature designed solely for heat dissipation. It must be soldered to a large PCB copper area connected to GND to reduce junction-to-ambient thermal resistance. It should never serve as the primary GND signal path, as doing so risks compromising both thermal performance and signal integrity.

Does AP7315D-285FS4-7B require an external discharge resistor?

No. The "D" suffix denotes integrated auto-discharge functionality: when EN is pulled low, an internal 30Ω NMOS switch actively discharges VOUT to GND. This eliminates the need for external resistors, reduces BOM count, and ensures sub-10µs VOUT decay - critical for precise power sequencing in multi-rail systems.

Can AP7315D-285FS4-7B operate with input voltage below 2.85V?

Yes - down to 1.7V minimum input. However, regulation is only maintained while VIN ≥ VOUT + dropout voltage. At 150mA load, dropout is 210mV typical, so minimum functional VIN is ~3.06V. Below that, output drops linearly; the device remains safe but ceases regulation.

How does the AP7315D variant differ from the standard AP7315 in layout requirements?

The AP7315D adds no new pins or layout constraints beyond the base AP7315. Both share identical pinout, thermal pad requirements, and decoupling recommendations. The discharge circuitry is fully internal and does not alter PCB routing, capacitor placement, or grounding strategy - simplifying migration from non-D to D variants.