Diodes Incorporated AP7354D-185FS4-7

Overview

AP7354D-185FS4-7 from Diodes Incorporated is a 150mA ultra-low quiescent current LDO regulator with fixed 1.85V output, ±1% accuracy at +25°C, 0.25µA typical quiescent current, and integrated active output discharge. It operates from 2.0V to 5.5V input and is designed for power management in space-constrained, battery-powered wearable and IoT sensor modules.

For engineers reviewing the AP7354D-185FS4-7 datasheet, AP7354D-185FS4-7 pinout, AP7354D-185FS4-7 application, or AP7354D-185FS4-7 equivalent, key selection criteria include dropout voltage at 150mA (0.32V typ), EN pin logic thresholds (0.4V low / 1.0V high), thermal resistance in X2-DFN1010-4 (295°C/W), and discharge resistance (35Ω).

Technical Context

The AP7354D integrates a precision voltage reference, error amplifier, current-limit circuit, and enable control logic to regulate output voltage with high DC accuracy and fast transient response. Its architecture supports stable operation with 0.1µF ceramic input/output capacitors and includes internal protection against short-circuit, overtemperature, and latch-up per JESD 78 Class I.

This device implements active output discharge via an internal NMOS switch tied to the EN pin, enabling rapid VOUT ramp-down during shutdown-critical for sequencing-sensitive systems. The X2-DFN1010-4 (Type B) package provides minimal footprint (1.0mm × 1.0mm) and optimized thermal performance for high-density PCB layouts.

Key Specifications

Pinout & Package

X2-DFN1010-4 (Type B) package: 1.0mm × 1.0mm body, 0.65mm pitch, no exposed pad; RoHS-compliant NiPdAu-plated terminals solderable per MIL-STD-202 Method 208.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1703T-1852E/MB and XC6219B185MR-G, the AP7354D-185FS4-7 uniquely combines 150mA drive, 0.25µA IQ, and integrated discharge in a 1.0mm × 1.0mm DFN-enabling smaller, longer-life, and more robustly sequenced designs.

Availability

AP7354D-185FS4-7 is available at Aetrix Electronics and suitable for wearable electronics, IoT sensor modules, and wireless communication devices requiring stable component supply with extended battery life and minimal PCB footprint.

Supply support for AP7354D-185FS4-7 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 solutions for power management, signal integrity, and connectivity applications.

The AP7354 series targets ultra-low-power portable electronics, delivering high-accuracy, low-noise regulation with minimal quiescent consumption for battery longevity and miniaturization.

FAQ

What is the minimum input voltage required for AP7354D-185FS4-7 to maintain regulation?

The AP7354D-185FS4-7 maintains regulation down to VIN = VOUT + dropout voltage. At 150mA load and +25°C, dropout is 0.32V typical, so minimum VIN is 2.17V. Over temperature and process variation, worst-case dropout reaches 0.58V, requiring ≥2.43V input for guaranteed 1.85V output.

Does AP7354D-185FS4-7 require external capacitors, and what values are recommended?

Yes: a 0.1µF ceramic capacitor is required between VIN and GND, and another 0.1µF ceramic capacitor between VOUT and GND. X5R or X7R dielectrics are recommended for stable capacitance and low ESR across -40°C to +85°C. Placement must be adjacent to respective pins with short, low-inductance traces.

Can the EN pin be left unconnected, or does it require a defined logic level?

The EN pin must never float. It must be actively driven high (≥1.0V) to enable regulation or pulled low (≤0.4V) to enter shutdown with active discharge. If unused, tie EN directly to VIN to ensure permanent enable-do not connect through a resistor, as leakage could cause unintended shutdown.

How does the active output discharge function impact system-level power sequencing?

The internal 35Ω discharge path pulls VOUT to GND within microseconds after EN goes low, preventing back-powering of upstream regulators or leakage into disabled circuit blocks. This eliminates need for external bleed resistors and ensures deterministic power-down timing in multi-supply systems with strict sequencing requirements.