Diodes Incorporated AP7343D-36FS4-7B

Overview

AP7343D-36FS4-7B from Diodes Incorporated is a 300mA, 3.6V fixed-output low-dropout (LDO) regulator in X2-DFN1010-4 (Type B) package, featuring ±1% output voltage accuracy, 75dB PSRR at 1kHz, 60µV_rms output noise (10Hz–100kHz), and 35µA quiescent current. It integrates enable control, thermal shutdown, and short-circuit protection, and is optimized for RF supply rails in compact portable electronics.

For engineers reviewing the AP7343D-36FS4-7B datasheet, AP7343D-36FS4-7B pinout, AP7343D-36FS4-7B application, or AP7343D-36FS4-7B equivalent, key selection criteria include dropout voltage at 300mA (0.22–0.29V), EN logic thresholds (0.5V low / 1.3V high), discharge functionality (enabled by 'D' suffix), and thermal resistance (R_θJA = 237°C/W).

Technical Context

The AP7343D-36FS4-7B uses a CMOS-based architecture with integrated voltage reference, error amplifier, and current-limit circuitry. Its enable input directly controls NMOS pass transistor gate bias, enabling fast turn-on/turn-off transitions (<200µs) and supporting dynamic power sequencing in multi-rail systems.

It incorporates auto-discharge functionality via an internal 30Ω N-channel switch between VOUT and GND when EN is low, ensuring rapid output voltage decay to prevent back-powering of downstream circuitry. Thermal shutdown activates at +150°C with +20°C hysteresis, and short-circuit current is clamped to ~55mA.

Key Specifications

Pinout & Package

X2-DFN1010-4 (Type B) package: 1.0mm × 1.0mm, 0.4mm pitch, exposed thermal pad (EP) - connect to GND 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 MCP1703-3302E/MB and XC6210B362MR-G, the AP7343D-36FS4-7B uniquely combines 3.6V output, 300mA capability, sub-40µA quiescent current, and integrated discharge-making it optimal for space-constrained, battery-powered RF and imaging subsystems requiring controlled power sequencing.

Availability

AP7343D-36FS4-7B is available at Aetrix Electronics and suitable for RF power amplifier biasing, camera module core regulation, wireless adapter SoC core rails, and portable media player audio codec supplies requiring stable component supply across production volumes.

Supply support for AP7343D-36FS4-7B 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-PSRR, low-noise LDO product line, designed specifically for noise-sensitive portable communication equipment including smartphones, tablets, and wireless infrastructure modules.

FAQ

What is the purpose of the exposed pad (EP) on the AP7343D-36FS4-7B?

The exposed pad is a thermal interface-not an electrical terminal-and must be soldered to a PCB copper pour connected to GND for heat dissipation. It reduces junction-to-board thermal resistance to 85.7°C/W but must not serve as the sole GND connection; dedicated PIN2 (GND) remains the primary current return path.

Does the 'D' in AP7343D-36FS4-7B indicate a different package or electrical specification?

The 'D' suffix denotes built-in auto-discharge functionality: when EN is pulled low, an internal 30Ω NMOS switch connects VOUT to GND, discharging the output capacitor rapidly. Electrical specs-including 3.6V output, 300mA rating, and 75dB PSRR-are identical to non-D variants; only discharge behavior differs.

Can AP7343D-36FS4-7B operate with input voltage below 3.6V?

Yes-it supports VIN as low as 1.7V and maintains regulation down to VIN = VOUT + dropout voltage. At 300mA load and 3.6V output, minimum VIN is 3.82V (3.6V + 0.22V). Below that, output drops linearly; operation below 3.6V input is valid only if dropout margin is maintained.

How does the AP7343D-36FS4-7B handle short-circuit conditions?

Under VOUT-to-GND short, the device limits output current to ~55mA via foldback protection and activates thermal shutdown if junction temperature exceeds +150°C. Recovery is automatic after fault removal and cooldown; no latch-up occurs, and EN retains full control over restart timing.