Diodes Incorporated AP7343D-25FS4-7B

Overview

AP7343D-25FS4-7B from Diodes Incorporated is a 300mA, 2.5V fixed-output 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 operates from 1.7V to 5.25V input, features CMOS-based architecture, and targets RF supply rails and portable media subsystems where clean, stable biasing is critical.

For engineers reviewing the AP7343D-25FS4-7B datasheet, AP7343D-25FS4-7B pinout, AP7343D-25FS4-7B application, or AP7343D-25FS4-7B equivalent, key selection criteria include dropout voltage at 300mA (0.25–0.30V for V_OUT = 2.5V), thermal resistance (R_θJA = 237°C/W in X2-DFN1010-4), EN logic thresholds (V_IL ≤ 0.5V, V_IH ≥ 1.3V), and built-in discharge functionality.

Technical Context

The AP7343D integrates a precision voltage reference, error amplifier, current-limit circuit, and thermal shutdown protection within a CMOS process. Its enable input directly controls NMOS pass transistor gate drive, enabling fast turn-on/turn-off with controlled discharge via an internal 30Ω N-channel switch when disabled.

Designed for low-noise analog and RF subsystems, it delivers stable regulation under rapid load transients (e.g., 1mA ↔ 300mA steps) without external compensation, supported by stability with ≥1µF ceramic C_OUT. The X2-DFN1010-4 (Type B) package uses an exposed pad optimized for thermal dissipation to PCB ground planes.

Key Specifications

Pinout & Package

X2-DFN1010-4 (Type B) package: 1.0mm × 1.0mm, 0.4mm pitch, exposed thermal pad (EP). Pin 1 (VOUT) and Pin 4 (VIN) are on opposite corners; EP must be connected to GND plane for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700-2502E/TO and XC6210B252MR-G, the AP7343D-25FS4-7B uniquely combines 300mA capability, 60µV_rms noise, 75dB PSRR, enable control, and built-in discharge in a 1.0×1.0mm DFN - making it optimal for space-constrained, multi-rail portable systems requiring clean, sequenced power.

Availability

AP7343D-25FS4-7B is available at Aetrix Electronics and suitable for RF power amplifier biasing, camera sensor core supplies, portable media player audio codecs, and wireless adapter baseband ICs requiring stable component supply with guaranteed long-term availability.

Supply support for AP7343D-25FS4-7B 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 high-reliability power management, signal integrity, and protection solutions for consumer, industrial, and automotive markets.

The AP7343 series belongs to Diodes' high-PSRR, low-noise LDO product line, engineered specifically for noise-sensitive RF, imaging, and audio subsystems in battery-powered portable electronics.

FAQ

What is the minimum input voltage required for AP7343D-25FS4-7B to maintain 2.5V output at 300mA?

The minimum input voltage is determined by dropout voltage: at 300mA and 2.5V output, typical dropout is 0.25V, so VIN must be ≥ 2.75V. Absolute minimum VIN per datasheet is 1.7V, but regulation fails below 2.75V under full load. Thermal derating applies above +85°C ambient.

Does AP7343D-25FS4-7B require an external discharge resistor?

No. The "D" suffix indicates built-in discharge functionality: when EN is pulled low, an internal 30Ω NMOS switch actively discharges VOUT to GND. This eliminates need for external resistors and ensures rapid, controlled VOUT decay during shutdown sequences.

Can AP7343D-25FS4-7B be used with ceramic output capacitors smaller than 1µF?

Stability is guaranteed with ≥1µF ceramic C_OUT; using smaller values risks oscillation or poor transient response. The datasheet specifies 1µF as minimum for all operating conditions. Lower capacitance may work in limited cases but violates design validation and voids performance guarantees.

How does the exposed pad (EP) on the X2-DFN1010-4 package affect thermal performance?

The EP reduces thermal resistance significantly: R_θJA drops from 237°C/W (no EP connection) to ~85°C/W when soldered to a 100mm² GND copper area. It must be connected to GND - not left floating - and should not serve as sole GND electrode; dedicated PIN2 (GND) remains the primary current return path.