Diodes Incorporated AP7343-105FS4-7B

Overview

AP7343-105FS4-7B from Diodes Incorporated is a 300mA, 1.05V fixed-output CMOS low-dropout regulator with ±1% output voltage accuracy, 75dB PSRR at 1kHz, and 60µV_rms output noise (10Hz–100kHz). It operates from 1.7V to 5.25V input, features enable control, thermal shutdown, and short-circuit protection, and is optimized for RF supply rails in compact portable devices.

For engineers reviewing the AP7343-105FS4-7B datasheet, AP7343-105FS4-7B pinout, AP7343-105FS4-7B application, or AP7343-105FS4-7B equivalent, key selection criteria include dropout voltage at 300mA (0.49V typ. for 1.05V output), quiescent current (35µA typ.), EN logic thresholds (0.5V low / 1.3V high), and X2-DFN1010-4 (Type B) thermal performance (R_θJA = 237°C/W).

Technical Context

The AP7343-105FS4-7B integrates a precision voltage reference, error amplifier, current-limit circuit, and NMOS pass transistor in a CMOS process-enabling low R_DS(ON), high PSRR, and fast load transient response. Its internal resistor network fixes V_OUT at 1.05V with ±1% accuracy over temperature and line/load conditions.

Enable functionality is implemented via a dedicated EN pin (Pin 3) with defined logic thresholds (V_EN(H) ≥ 1.3V, V_EN(L) ≤ 0.5V); floating EN is prohibited. Thermal shutdown activates at +150°C with +20°C hysteresis, and short-circuit protection limits output current to ~55mA when V_OUT is shorted to GND.

Key Specifications

Pinout & Package

X2-DFN1010-4 (Type B) package: 1.0mm × 1.0mm, 0.4mm pitch, exposed pad (EP) for thermal dissipation-requires PCB copper area connected to GND for optimal 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-105I/OT and TPS7A0510PDBVR, the AP7343-105FS4-7B uniquely delivers 300mA output with 75dB PSRR and 60µV_rms noise in a 1.0mm × 1.0mm DFN-making it the only viable choice for space-constrained, high-current RF and imaging subsystems requiring simultaneous low noise and high ripple rejection.

Availability

AP7343-105FS4-7B is available at Aetrix Electronics and suitable for smartphone baseband power, RF transceiver bias, camera ISP supplies, and portable media player audio DACs requiring stable component supply, full RoHS/Green compliance, and automotive-grade traceability.

Supply support for AP7343-105FS4-7B 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-with emphasis on high-reliability, low-power solutions.

The AP7343 series belongs to Diodes' high-PSRR, low-noise LDO product line, engineered specifically for noise-sensitive portable electronics including smartphones, tablets, and wireless communication modules.

FAQ

What is the minimum input voltage required for AP7343-105FS4-7B to regulate 1.05V output at 300mA?

The minimum input voltage is determined by dropout: typical 0.49V at 300mA for 1.05V output, so VIN(min) = 1.05V + 0.49V = 1.54V. However, the absolute minimum specified operating VIN is 1.7V per datasheet-ensuring guaranteed regulation, PSRR, and thermal margin across temperature and process variation.

Can the EN pin be left unconnected if always-on operation is desired?

No-EN must never be left floating. For always-on operation, tie EN directly to VIN using a low-impedance connection. Floating EN risks partial turn-on, increased quiescent current, or erratic behavior due to noise coupling; the datasheet explicitly states "must not be floating" and defines valid logic thresholds.

Is AP7343-105FS4-7B qualified for automotive applications?

No-the AP7343-105FS4-7B is an industrial-grade part rated for –40°C to +85°C ambient. Automotive qualification requires the AP7343Q variant, which undergoes AEC-Q100 stress testing and is documented in a separate datasheet (DS37952Q) with extended temperature range and enhanced reliability screening.

What is the recommended output capacitor for optimal transient response at 300mA load steps?

A 1µF X5R/X7R ceramic capacitor placed within 1mm of VOUT and GND pins is recommended. For improved load step recovery (e.g., 1mA→300mA), add a parallel 4.7µF low-ESR ceramic-reducing output voltage deviation from ±40mV to ±15mV per typical load transient waveforms in the datasheet.