Diodes Incorporated AP7340D-36FS4-7

Overview

AP7340D-36FS4-7 from Diodes Incorporated is a 3.6V fixed-output, 150mA low-dropout linear regulator with ±1% output voltage accuracy, 75dB PSRR at 1kHz, and 60µV_rms output noise (10Hz–100kHz). It features CMOS-based architecture, enable control, and integrated auto-discharge functionality. Designed for RF supply rails in portable wireless communication devices, it operates from 1.7V to 5.25V input and delivers stable bias under fast load transients.

For engineers reviewing the AP7340D-36FS4-7 datasheet, AP7340D-36FS4-7 pinout, AP7340D-36FS4-7 application, or AP7340D-36FS4-7 equivalent, key selection criteria include dropout voltage (210mV @ 150mA for 3.6V output), quiescent current (35µA typical), EN logic thresholds (0.5V_IL/1.3V_IH), and X2-DFN1010-4 thermal pad layout requirements.

Technical Context

The AP7340D integrates a precision voltage reference, error amplifier, current-limit circuit, and NMOS pass transistor with built-in discharge path (enabled when EN = low). Its CMOS process enables ultra-low quiescent current and high PSRR across 1kHz–100kHz frequencies.

It supports fast transient response via low-ESR ceramic capacitors (0.47µF C_IN/C_OUT) and includes short-circuit protection clamping output current to ~55mA. The thermal pad must be connected to GND or large copper pour for 400mW power dissipation capability.

Key Specifications

Pinout & Package

X2-DFN1010-4 package: 1.0mm × 1.0mm footprint, 0.4mm height, thermal pad on underside for PCB heat sinking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-3602E/TT and XC6219B362MR-G, the AP7340D-36FS4-7 uniquely combines 3.6V fixed output, integrated discharge, 75dB PSRR, and 1.0mm² DFN packaging-making it optimal for space-constrained RF and imaging modules requiring controlled shutdown behavior.

Availability

AP7340D-36FS4-7 is available at Aetrix Electronics and suitable for RF transceiver bias, camera sensor core supply, and wireless adapter module designs requiring stable component supply, tight voltage tolerance, and compact packaging.

Supply support for AP7340D-36FS4-7 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 manufacturer of discrete semiconductors and analog ICs, specializing in high-performance power management, signal integrity, and protection solutions for consumer, industrial, and communications markets.

The AP7340 series belongs to Diodes' high-PSRR, low-noise LDO product line, engineered specifically for noise-sensitive RF, imaging, and portable communication applications demanding minimal footprint and precise voltage regulation.

FAQ

What is the minimum input voltage required for AP7340D-36FS4-7 to maintain regulation at 150mA load?

The minimum input voltage is calculated as V_OUT + V_DROP = 3.6V + 0.21V = 3.81V. This value is confirmed by the Electrical Characteristics table for V_OUT ≥ 2.8V, where dropout voltage is specified as 0.21V (typ) / 0.27V (max) at 150mA. Operation below 3.81V results in loss of regulation and output droop.

Does AP7340D-36FS4-7 require an external pull-up resistor on the EN pin?

No. The EN pin has an internal pull-down; tying it directly to VIN enables the regulator, while grounding it disables it. An external pull-up is unnecessary and may conflict with the internal bias. If left unconnected, the internal pull-down ensures default shutdown-critical for systems requiring fail-safe power sequencing.

How does the auto-discharge feature function, and what is its on-resistance?

When EN is driven low, an internal 30Ω NMOS transistor connects VOUT to GND, discharging output capacitance. Measured on-resistance is 30Ω (typ), enabling rapid discharge of ≤10µF loads within 100µs. This prevents back-powering of upstream circuitry and ensures clean power-down sequencing in multi-rail systems.

Can AP7340D-36FS4-7 be used with ceramic output capacitors smaller than 0.47µF?

No. The datasheet specifies stability with ≥0.47µF ceramic capacitors (X5R/X7R, ≤10mΩ ESR). Using smaller values risks oscillation due to insufficient phase margin, especially under load transients. Layout must place the capacitor within 2mm of VOUT and GND pins to minimize parasitic inductance and ensure stability.