Diodes Incorporated AP7343D-29FS4-7B

Overview

AP7343D-29FS4-7B from Diodes Incorporated is a 300mA, 2.9V 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. Fabricated on a CMOS process, it delivers stable power to RF supplies and camera modules in space-constrained portable electronics using its X2-DFN1010-4 (Type B) package.

For engineers reviewing the AP7343D-29FS4-7B datasheet, AP7343D-29FS4-7B pinout, AP7343D-29FS4-7B application, or AP7343D-29FS4-7B equivalent, key selection criteria include dropout voltage (≤290mV at 300mA for V_OUT = 2.9V), quiescent current (35µA typ.), thermal shutdown threshold (+150°C), and compatibility with 1µF ceramic input/output capacitors.

Technical Context

The AP7343D-29FS4-7B integrates a precision voltage reference, error amplifier, current-limit circuit, and thermal shutdown protection within a single CMOS LDO architecture. Its enable (EN) pin provides precise on/off control with defined logic thresholds (V_IL ≤ 0.5V, V_IH ≥ 1.3V), and the built-in discharge function actively pulls V_OUT to GND during shutdown-critical for systems requiring rapid rail collapse.

This variant features the X2-DFN1010-4 (Type B) package with an exposed pad (EP) optimized for thermal dissipation (R_θJA = 237°C/W), and supports operation across –40°C to +85°C ambient. It maintains regulation down to 1.7V input and sustains 300mA output current with <30mV load regulation over full load range.

Key Specifications

Pinout & Package

X2-DFN1010-4 (Type B) package: 1.0mm × 1.0mm, 0.4mm pitch, 4 active terminals + exposed thermal pad (EP). EP must be connected to PCB ground plane for optimal thermal performance (R_θJB = 85.7°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1703T-2902E/MB and XC6219B292MR-G, the AP7343D-29FS4-7B offers superior PSRR, integrated discharge, tighter output accuracy, and a 40% smaller footprint-making it optimal for ultra-compact, battery-sensitive RF and imaging subsystems where rail collapse timing and noise immunity are design-critical.

Availability

AP7343D-29FS4-7B is available at Aetrix Electronics and suitable for RF power amplifier biasing, CMOS image sensor core supply, portable media player audio codec power, and wireless adapter baseband IC applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for AP7343D-29FS4-7B 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 AP7343 series belongs to Diodes' high-performance LDO portfolio, designed specifically for noise-sensitive, battery-powered portable electronics requiring ultra-low quiescent current, high PSRR, and compact packaging.

FAQ

What is the maximum input voltage rating for AP7343D-29FS4-7B?

The absolute maximum input voltage (VIN) is 6.0V per the datasheet Absolute Maximum Ratings table. However, recommended operating conditions specify VIN up to 5.25V. Exceeding 5.25V may not damage the device immediately but risks violating thermal limits and degrading long-term reliability-especially under 300mA load in the X2-DFN1010-4 package.

Does AP7343D-29FS4-7B require an external discharge resistor?

No. The "D" suffix denotes the integrated discharge FET variant, which actively pulls VOUT to GND when EN is low. This eliminates the need for an external bleed resistor, reducing BOM count and PCB area while ensuring predictable, sub-millisecond rail decay-essential for systems with strict power sequencing requirements.

Can AP7343D-29FS4-7B operate with only a 0.47µF input capacitor?

Yes-the datasheet specifies a minimum 0.47µF ceramic capacitor between VIN and GND. For optimal line transient response and stability, especially with fast-switching loads like RF PAs, a 1µF X5R/X7R ceramic placed within 2mm of the VIN/GND pins is strongly recommended per Application Information guidelines.

How does the exposed pad (EP) affect thermal performance?

The EP is a thermal conduction path-not an electrical terminal. When soldered to ≥25mm² of PCB copper tied to GND, it reduces R_θJA from 237°C/W to ~120°C/W in typical 2-layer boards. Leaving it unconnected or floating increases junction temperature by up to 45°C at 300mA, risking thermal shutdown or accelerated parametric drift.