Diodes Incorporated AP7343D-11FS4-7B

Overview

AP7343D-11FS4-7B from Diodes Incorporated is a 300mA, 1.1V fixed-output low-dropout linear regulator with high PSRR (75dB at 1kHz), ultra-low output noise (60µVrms), ±1% output voltage accuracy, and enable-controlled shutdown. It employs CMOS process technology and integrates current limiting, thermal shutdown, and an internal resistor network for stable fixed-voltage regulation. This LDO powers sensitive RF supplies and camera modules in space-constrained portable electronics.

For engineers reviewing the AP7343D-11FS4-7B datasheet, AP7343D-11FS4-7B pinout, AP7343D-11FS4-7B application, or AP7343D-11FS4-7B equivalent, key selection criteria include its 1.7V–5.25V input range, 35µA quiescent current, 0.39V typical dropout at 300mA (1.1V output), X2-DFN1010-4 (Type B) package footprint, and built-in discharge function for rapid VOUT decay during shutdown.

Technical Context

The AP7343D-11FS4-7B implements a CMOS-based LDO architecture with a precision voltage reference, error amplifier, and N-channel pass transistor. Its enable input (EN) provides active-high control with defined logic thresholds (0–0.5V low, 1.3–5.25V high) and <1.0µA leakage, enabling precise power sequencing.

It features integrated short-circuit protection (≈55mA fold-back limit), thermal shutdown at +150°C with +20°C hysteresis, and stability with 1µF ceramic output capacitors. The built-in discharge path (enabled by the "D" suffix) uses a 30Ω on-resistance NMOS to actively pull VOUT to GND when EN is low, eliminating external discharge circuitry.

Key Specifications

Pinout & Package

X2-DFN1010-4 (Type B) is a 1.0mm × 1.0mm, 0.4mm pitch, 4-terminal surface-mount package with exposed thermal pad (EP). Optimized for minimal PCB area and high thermal efficiency (R_θJA = 237°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700-1102E/TO and XC6210B112MR-G, the AP7343D-11FS4-7B uniquely combines 300mA capability, 75dB PSRR, 60µVrms noise, and integrated discharge in a 1.0mm² DFN-making it optimal for next-gen compact RF and imaging subsystems demanding full feature integration.

Availability

AP7343D-11FS4-7B is available at Aetrix Electronics and suitable for RF power amplifier bias, CMOS image sensor core supply, low-power microcontroller core rails, and wireless communication SoC I/O supply requiring stable component supply across high-mix production runs.

Supply support for AP7343D-11FS4-7B 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 ICs for power management, signal integrity, and connectivity applications.

The AP7343 series belongs to Diodes' high-performance LDO portfolio, engineered specifically for battery-powered portable electronics requiring ultra-low noise, high PSRR, and minimal footprint.

FAQ

What is the purpose of the exposed pad (EP) on the X2-DFN1010-4 package?

The exposed pad serves primarily as a thermal conduction path-not a functional ground electrode. It must be soldered to a large PCB copper area connected to the system GND plane to achieve optimal thermal performance (R_θJB = 85.7°C/W). Using it solely as the GND connection without adequate copper area degrades thermal resistance and risks overheating.

Does the AP7343D-11FS4-7B require an external discharge resistor?

No. The "D" suffix denotes integrated discharge functionality: an internal 30Ω NMOS connects VOUT to GND when EN is low, collapsing output voltage in under 1ms. This eliminates the need for external resistors or FETs, saving board space and reducing BOM count in portable designs.

How does the AP7343D-11FS4-7B maintain stability with only 1µF output capacitance?

Its CMOS-based control loop and internal compensation are optimized for ceramic capacitors with ESR <10mΩ. Stability is guaranteed across 1µF–10µF output capacitance values, provided the capacitor is placed within 2mm of VOUT and GND pins and uses X5R/X7R dielectric with low parasitic inductance.

Can the AP7343D-11FS4-7B operate from a 1.8V input when regulating 1.1V output?

Yes. With a typical dropout voltage of 0.39V at 300mA, the device regulates stably down to VIN = 1.49V. At 1.8V input, it delivers full 300mA with margin, making it suitable for partial-discharge battery operation in single-cell Li-ion systems (2.8–4.2V nominal, down to ~2.5V).