Diodes Incorporated AP7343D-12FS4-7B

Overview

AP7343D-12FS4-7B from Diodes Incorporated is a 300mA, 1.2V fixed-output low-dropout linear regulator with high PSRR (75dB at 1kHz), ultra-low output noise (60µVrms, 10Hz–100kHz), ±1% output voltage accuracy, and enable-controlled shutdown. Packaged in X2-DFN1010-4 (Type B), it delivers stable power to RF supplies and camera modules in space-constrained portable electronics.

For engineers reviewing the AP7343D-12FS4-7B datasheet, AP7343D-12FS4-7B pinout, AP7343D-12FS4-7B application, or AP7343D-12FS4-7B equivalent, key selection criteria include dropout voltage (≤390mV @300mA, VOUT=1.2V), quiescent current (35µA typ), thermal shutdown threshold (+150°C), and EN logic compatibility (VIH ≥1.3V, VIL ≤0.5V).

Technical Context

The AP7343D-12FS4-7B integrates a CMOS-based pass transistor, precision voltage reference, error amplifier, current-limit circuit, and thermal shutdown protection. Its architecture supports fast load transient response (<100µs recovery for 1mA↔300mA steps) and includes an internal discharge FET (enabled by "D" suffix) that actively pulls VOUT to GND during shutdown.

It operates across 1.7V–5.25V input range with guaranteed 300mA output, maintains regulation down to 390mV dropout at 1.2V output, and features built-in short-circuit protection clamping output current to ~60mA under VOUT-to-GND fault conditions.

Key Specifications

Pinout & Package

AP7343D-12FS4-7B uses the X2-DFN1010-4 (Type B) package - a 1.0mm × 1.0mm, 0.4mm pitch, 4-terminal surface-mount package with exposed thermal pad (EP). The EP must be connected to PCB ground 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 MCP1703T-1202E/MB and XC6210B122MR-G, the AP7343D-12FS4-7B uniquely combines 300mA capability, 75dB PSRR, integrated discharge, and 1.0mm² DFN packaging - making it optimal for miniaturized, enable-controlled, noise-sensitive RF and imaging systems.

Availability

AP7343D-12FS4-7B is available at Aetrix Electronics and suitable for smartphone camera modules, RF front-end biasing, wearable health sensor nodes, and portable media player audio codecs requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for AP7343D-12FS4-7B 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 devices, with design centers across Asia, Europe, and the US, serving automotive, industrial, computing, and consumer markets.

The AP7343 series belongs to Diodes' high-performance LDO portfolio, engineered specifically for noise-critical, space-constrained portable electronics requiring precision voltage regulation, fast transient response, and robust protection.

FAQ

What is the maximum allowable input voltage for AP7343D-12FS4-7B?

The absolute maximum input voltage is 6.0V, but recommended operating range is 1.7V to 5.25V. Exceeding 5.25V risks violating safe operating area limits and may trigger thermal shutdown or degrade long-term reliability. Operation above 5.25V is not characterized or guaranteed per datasheet specifications.

Does AP7343D-12FS4-7B require an external discharge resistor?

No - the "D" suffix indicates integrated discharge FET functionality. When EN is pulled low, the internal 30Ω FET actively discharges VOUT to GND, eliminating need for external resistor. This reduces BOM count and PCB area while ensuring predictable shutdown behavior in systems with capacitive loads.

Can AP7343D-12FS4-7B operate with ceramic output capacitors smaller than 1µF?

Yes - the device is stable with ≥0.47µF ceramic capacitors. However, 1µF is recommended for optimal transient response across full 300mA load range. Using <1µF may increase output voltage deviation during large load steps, especially with COUT ESR >10mΩ, as confirmed in ESR vs. IOUT stability graphs (DS37952 p.12).

How does thermal performance differ between X2-DFN1010-4 and SOT25 packages?

X2-DFN1010-4 (Type B) has R_θJA = 237°C/W (JEDEC standard board), while SOT25 achieves 179°C/W. The DFN's exposed pad enables superior heat transfer to PCB ground plane, reducing junction temperature rise by ~25% under identical 300mA load - critical for sustained operation in sealed enclosures or high-ambient environments.