Diodes Incorporated AP7343D-15FS4-7B

Overview

AP7343D-15FS4-7B from Diodes Incorporated is a 300mA, 1.5V 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. Packaged in X2-DFN1010-4 (Type B), it delivers stable power to RF supplies, camera modules, and portable media subsystems where low quiescent current (35µA) and fast load transient response are critical.

For engineers reviewing the AP7343D-15FS4-7B datasheet, AP7343D-15FS4-7B pinout, AP7343D-15FS4-7B application, or AP7343D-15FS4-7B equivalent, this page provides verified functional context, validated pin-level circuit roles, confirmed thermal and noise performance metrics, and real-world design implications for battery-powered handheld systems.

Technical Context

The AP7343D-15FS4-7B integrates a CMOS-based error amplifier, precision voltage reference, current-limit circuit, and thermal shutdown protection. Its enable input (EN) directly controls NMOS pass transistor conduction, supporting active-high logic control with defined thresholds (V_IL ≤ 0.5V, V_IH ≥ 1.3V).

This variant includes an internal discharge FET (enabled by "D" suffix), actively pulling VOUT to GND during shutdown to prevent floating rail conditions-critical for multi-rail sequencing in smartphones and wireless adapters. Dropout voltage is 0.46V max at 300mA for 1.5V output in the X2-DFN1010-4 package.

Key Specifications

Pinout & Package

X2-DFN1010-4 (Type B) package: 1.0mm × 1.0mm, 0.4mm pitch, exposed thermal pad (EP) - optimized for ultra-dense mobile PCBs. EP must be connected to GND via multiple vias for thermal dissipation; not used as primary GND electrode.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP7343D-15FS4-7B, AP7361D-15FS4-7B trades lower noise and tighter accuracy for higher current capacity, while MCP1826T-1502E/DB sacrifices discharge capability and noise performance for broader vendor availability and lower unit cost-making AP7343D-15FS4-7B optimal for compact, noise-critical, sequenced-power applications.

Availability

AP7343D-15FS4-7B is available at Aetrix Electronics and suitable for smartphone camera modules, RF power amplifier biasing, and portable media player audio codecs requiring stable component supply, guaranteed RoHS/Green compliance, and automotive-grade traceability (via AP7343Q variant).

Supply support for AP7343D-15FS4-7B 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 targets ultra-low-noise, high-PSRR power delivery in space-constrained portable electronics-designed specifically for RF, imaging, and audio subsystems demanding sub-100µV_rms noise and precise voltage regulation.

FAQ

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

The exposed pad is a thermal dissipation feature-not an electrical terminal. It must be soldered to a GND-connected copper pour using ≥4 thermal vias to achieve the specified R_θJB = 85.7°C/W. Leaving it unconnected raises junction temperature by up to 40°C at 300mA, risking thermal shutdown.

Does the "D" in AP7343D-15FS4-7B affect electrical performance beyond discharge functionality?

No-the "D" suffix denotes inclusion of an internal discharge FET only. All electrical specifications-including output accuracy, PSRR, noise, dropout, and quiescent current-are identical to non-D variants. The discharge path activates solely when EN = low and adds <1µA standby current.

Can AP7343D-15FS4-7B operate with input voltage below 1.7V?

No-1.7V is the absolute minimum input voltage per datasheet. At 1.5V input, the device fails to regulate: output collapses to ~0.8V at 100mA load due to insufficient headroom for the pass transistor's R_DS(ON) and error amplifier headroom.

Is a minimum output capacitance required for stability, and what type is recommended?

Yes-1µF X5R/X7R ceramic capacitor is the minimum stable value. Lower capacitance (e.g., 0.47µF) risks oscillation under load transients. Capacitor ESR must be <10mΩ; tantalum or aluminum electrolytics are unstable and not recommended.