Diodes Incorporated AP7343D-21W5-7

Overview

AP7343D-21W5-7 from Diodes Incorporated is a 300mA low-dropout linear regulator with fixed 2.1V output, ±1% accuracy, 75dB PSRR at 1kHz, 60µV_rms output noise (10Hz–100kHz), and 35µA quiescent current. It features CMOS-based architecture, enable control, thermal shutdown, and short-circuit protection-designed for RF supply rails in space-constrained portable electronics.

For engineers reviewing the AP7343D-21W5-7 datasheet, AP7343D-21W5-7 pinout, AP7343D-21W5-7 application, or AP7343D-21W5-7 equivalent, key selection criteria include dropout voltage at 300mA (0.30V typ. for 2.1V V_OUT), EN logic thresholds (0.5V low / 1.3V high), thermal resistance (179°C/W in SOT25), and discharge functionality enabled by the "D" suffix.

Technical Context

The AP7343D-21W5-7 integrates a precision voltage reference, error amplifier, current-limit circuit, and NMOS pass transistor with built-in auto-discharge path. Its CMOS process enables ultra-low quiescent current (35µA) while maintaining fast load transient response (<100µs recovery with 1µF C_OUT) and stable operation down to 0.47µF ceramic input capacitance.

It operates across 1.7V–5.25V input range and delivers regulated 2.1V output with ±1% initial accuracy and ±30ppm/°C temperature coefficient. The device includes thermal shutdown at +150°C with +20°C hysteresis and fold-back short-circuit current limiting (~55mA).

Key Specifications

Pinout & Package

AP7343D-21W5-7 is packaged in SOT25 (5-pin, 2.9mm × 1.6mm × 1.1mm), featuring an exposed thermal pad (EP) for enhanced heat dissipation. The package supports reflow soldering per J-STD-020 and achieves 179°C/W junction-to-ambient thermal resistance on standard JEDEC High-K board.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP7343D-21W5-7, AP7361D-21SAG-7 trades board area for headroom in current and thermal performance, while MCP1700T-2102E/TT sacrifices noise suppression and integrated safety features for lower unit cost-making AP7343D-21W5-7 optimal for compact, noise-sensitive RF and imaging applications requiring guaranteed discharge behavior.

Availability

AP7343D-21W5-7 is available at Aetrix Electronics and suitable for RF power amplifier supplies, camera ISP cores, Bluetooth baseband ICs, and wearable sensor hub MCUs requiring stable component supply, automotive-grade traceability, and long-term lifecycle support.

Supply support for AP7343D-21W5-7 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-PSRR, low-noise LDO portfolio, engineered specifically for noise-sensitive portable electronics where RF performance, battery life, and PCB area are critical design constraints.

FAQ

What is the purpose of the "D" suffix in AP7343D-21W5-7?

The "D" denotes integrated auto-discharge functionality: when the EN pin is pulled low, an internal 30Ω NMOS switch connects VOUT to GND, actively discharging output capacitance within microseconds. This prevents back-powering of upstream circuits or latch-up in multi-rail systems-critical for reliable power sequencing in smartphones and wearables.

Can AP7343D-21W5-7 operate with input voltage below 2.1V?

No-it requires VIN ≥ VOUT + dropout voltage. At 300mA load and 2.1V output, minimum VIN is 2.4V (2.1V + 0.30V typ. dropout). Below this, regulation fails and VOUT drops linearly with VIN. For sub-2.1V operation, consider AP7343 variants with lower VOUT (e.g., 1.8V or 1.2V) or ultra-low-dropout alternatives.

Is the exposed pad (EP) in SOT25 electrically connected to GND?

No-the EP is thermally conductive but electrically isolated. It must be soldered to a large GND copper pour for heat dissipation, yet should never serve as the primary GND connection. The dedicated Pin 2 (GND) remains the sole electrical ground reference; using EP as GND risks violating internal isolation and degrading thermal performance.

How does AP7343D-21W5-7 handle short-circuit conditions?

Under VOUT-to-GND short, the device activates fold-back current limiting, clamping output current to ~55mA. Simultaneously, thermal shutdown triggers at +150°C junction temperature with +20°C hysteresis. These dual protections prevent permanent damage during sustained faults and allow automatic recovery once fault clears and temperature falls below +130°C.