Diodes Incorporated AP7343D-27FS4-7B

Overview

AP7343D-27FS4-7B from Diodes Incorporated is a 300mA, 2.7V 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 - optimized for RF supply rails in compact portable devices.

For engineers reviewing the AP7343D-27FS4-7B datasheet, AP7343D-27FS4-7B pinout, AP7343D-27FS4-7B application, or AP7343D-27FS4-7B equivalent, key selection criteria include dropout voltage ≤290mV at 300mA (for V_OUT = 2.7V), enable-controlled shutdown with <1.0µA standby current, thermal shutdown at +150°C, and compatibility with 1µF ceramic input/output capacitors.

Technical Context

The AP7343D-27FS4-7B implements a CMOS-based LDO architecture with integrated voltage reference, error amplifier, current limit, and thermal shutdown circuitry. Its enable input (EN) provides precise on/off control with logic-compatible thresholds (V_IL ≤ 0.5V, V_IH ≥ 1.3V), and the "D" suffix denotes built-in output discharge functionality during shutdown.

This variant delivers fixed 2.7V output via internal resistor network, supports input voltages from 1.7V to 5.25V, and maintains regulation under load transients up to 300mA with <30mV load regulation error. The X2-DFN1010-4 (Type B) package includes an exposed pad for enhanced thermal dissipation (R_θJA = 237°C/W).

Key Specifications

Pinout & Package

X2-DFN1010-4 (Type B) package: 1.0mm × 1.0mm, 0.4mm pitch, exposed thermal pad (EP) - requires connection 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 MCP1700T-2702E/MB and XC6210B272MR-G, the AP7343D-27FS4-7B uniquely balances 300mA drive, integrated discharge, and industry-leading PSRR/noise trade-off in the smallest 1.0×1.0mm DFN footprint - making it optimal for space-constrained RF and imaging subsystems requiring robust sequencing and clean power.

Availability

AP7343D-27FS4-7B is available at Aetrix Electronics and suitable for RF power amplifier supplies, camera ISP rails, wireless communication modules, and portable medical sensor nodes requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for AP7343D-27FS4-7B 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, engineered specifically for noise-sensitive RF, imaging, and portable consumer electronics where small size, precision regulation, and fast transient response are critical.

FAQ

What is the purpose of the exposed pad (EP) on the AP7343D-27FS4-7B?

The exposed pad serves exclusively as a thermal conduction path - not an electrical terminal. It must be soldered to a dedicated GND copper pour (minimum 25mm²) to achieve the specified R_θJA = 237°C/W. Using it as a signal ground or leaving it unconnected degrades thermal performance by >40°C junction rise at full load.

Does the AP7343D-27FS4-7B require an external discharge FET?

No. The "D" suffix confirms integrated discharge functionality: when EN is pulled low, an internal ~30Ω NMOS switch actively pulls VOUT to GND, discharging output capacitance in <100µs (typical). This eliminates need for external components in power-rail sequencing applications.

Can the AP7343D-27FS4-7B operate with only 1µF output capacitance?

Yes - the device is internally compensated and stable with ≥1µF ceramic output capacitors (X5R/X7R, ≤10mΩ ESR). Larger values (e.g., 4.7µF) improve load transient response but are not required for stability. Avoid tantalum or aluminum electrolytics due to ESR/aging effects.

How does the AP7343D-27FS4-7B handle short-circuit conditions?

Under VOUT-to-GND short, the device activates fold-back current limiting, clamping output current to ~55mA (typical) while maintaining thermal shutdown protection at +150°C. This prevents damage during accidental shorts and allows safe auto-recovery once fault is removed.