Diodes Incorporated AP7353D-28FS4-7

Overview

AP7353D-28FS4-7 from Diodes Incorporated is a 250mA low-dropout linear regulator with fixed 2.8V output, ±1% accuracy, 90dB PSRR at 1kHz (10mA load), 10µV_rms output noise (10Hz–100kHz), and 18µA typical quiescent current. It features an enable input, thermal shutdown, short-circuit protection, and integrated auto-discharge functionality - designed for RF supply rails and noise-sensitive analog circuits in portable electronics.

For engineers reviewing the AP7353D-28FS4-7 datasheet, AP7353D-28FS4-7 pinout, AP7353D-28FS4-7 application, or AP7353D-28FS4-7 equivalent, key selection criteria include dropout voltage at 250mA (71–150mV), EN logic thresholds (0.4V low / 1.2V high), thermal resistance (237°C/W), and compatibility with 1µF ceramic output capacitors in space-constrained wearable designs.

Technical Context

The AP7353D-28FS4-7 implements a CMOS-based LDO architecture with internal voltage reference, error amplifier, current-limit circuit, and thermal shutdown. Its auto-discharge function actively pulls the output to ground when disabled via the EN pin, preventing residual voltage hold-up in battery-powered systems.

This device operates across 2.0V–5.5V input range and delivers stable 2.8V output with <0.02%/V line regulation and <0.004%/mA load regulation (X2-DFN1010-4 package). Fast load transient response (<20µs recovery) and high PSRR up to 90dB at 1kHz support clean power delivery to RF transceivers and high-speed ADCs.

Key Specifications

Pinout & Package

X2-DFN1010-4 (Type B) package: 1.0mm × 1.0mm, 0.65mm pitch, exposed thermal pad (EP), RoHS-compliant NiPdAu finish, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1703T-2802E/MB and XC6210B282MR-G, the AP7353D-28FS4-7 uniquely combines 250mA capability, 18µA IQ, EN control, and auto-discharge in a 1.0mm² footprint - making it optimal for space- and noise-constrained wireless edge devices requiring precise power sequencing.

Availability

AP7353D-28FS4-7 is available at Aetrix Electronics and suitable for smartphone camera modules, Bluetooth LE audio earbuds, wearable biosensors, and industrial LoRaWAN nodes requiring stable component supply with guaranteed long-term manufacturability.

Supply support for AP7353D-28FS4-7 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, with manufacturing certified to IATF 16949 and product definitions aligned to AEC-Q standards.

The AP7353 series belongs to Diodes' high-performance LDO portfolio targeting portable and wearable electronics, emphasizing low noise, high PSRR, and minimal footprint for battery-constrained applications.

FAQ

What is the minimum input voltage required for AP7353D-28FS4-7 to maintain regulation at 250mA?

The minimum input voltage is determined by dropout voltage: at 250mA and 2.8V output, typical dropout is 71mV (max 150mV). Thus, VIN must be ≥2.871V (typical) or ≥2.95V (worst-case) to sustain regulation. Below this, output voltage drops linearly with input.

Does AP7353D-28FS4-7 require an external capacitor on the EN pin for noise immunity?

No external EN capacitor is specified or recommended. The EN pin has defined logic thresholds (0.4V low, 1.2V high) and leakage <±1.0µA. For noisy environments, a 100kΩ pull-up to IN and short PCB trace are sufficient; adding capacitance risks violating turn-on time spec (180µs max).

Can the exposed pad (EP) of AP7353D-28FS4-7 be left unconnected in PCB layout?

No. The EP is thermally critical and must be soldered to a PCB copper area connected to GND. Leaving it unconnected increases θ_JA beyond 237°C/W, risking thermal shutdown at >150mA load in +85°C ambient. Minimum recommended copper area is 25mm² with 4+ thermal vias to inner ground planes.

How does the auto-discharge feature affect power sequencing in multi-rail systems?

When EN is pulled low, the internal 35Ω NMOS connects OUT to GND, discharging output capacitance within microseconds. This prevents back-powering of upstream regulators or latch-up in downstream logic, enabling safe, controlled power-down sequences in systems with multiple voltage domains.