Diodes Incorporated AP7368D-18RS4-7

Overview

AP7368D-18RS4-7 from Diodes Incorporated is a 500mA/1A low-noise RF LDO regulator in X1-DFN1612-8 (Type B) package, delivering fixed 1.8V output with ±1% accuracy, 80dB PSRR at 1kHz, and 16µV_rms output noise (10Hz–100kHz). It features dual current-limit selection (via LCON pin), 110µA quiescent current, and thermal shutdown at +150°C - deployed in RF power supply rails for smartphones and wireless adapters.

For engineers reviewing the AP7368D-18RS4-7 datasheet, AP7368D-18RS4-7 pinout, AP7368D-18RS4-7 application, or AP7368D-18RS4-7 equivalent, key selection criteria include output noise performance under RF-sensitive loads, LCON-configurable current limit for dynamic power scaling, dropout voltage at 1.8V output, and thermal resistance (θ_JA = 55.5°C/W) in ultra-compact DFN packaging.

Technical Context

The AP7368D-18RS4-7 integrates a CMOS-based error amplifier, precision voltage reference, foldback short-circuit protection, and enable-controlled N-channel auto-discharge path. Its architecture supports fast load transient response (<500ns rise/fall on EN) and stable operation with 1µF ceramic input/output capacitors.

Current limit is selected by LCON logic level: "H" enables 1A peak output with 110mA short-circuit clamp; "L" configures 500mA output with 60mA foldback. The device operates across 1.7V–5.5V input range and maintains ±30ppm/°C output voltage temperature coefficient over –40°C to +85°C ambient.

Key Specifications

Pinout & Package

X1-DFN1612-8 (Type B) package: 1.6mm × 1.2mm footprint, 0.4mm pitch, exposed thermal pad (EP) recommended to connect to GND plane for θ_JA = 55.5°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise RF LDO applications.

Compared with XC6216D182MR-G and RT9080-18GJ5, the AP7368D-18RS4-7 uniquely combines 1A/500mA configurability, industry-leading 16µV_rms noise, and foldback short-circuit protection - making it optimal for RF-critical, thermally constrained, and dynamically loaded portable systems.

Availability

AP7368D-18RS4-7 is available at Aetrix Electronics and suitable for smartphone RF power rails, wireless adapter baseband supplies, portable camera image sensor biasing, and Bluetooth LE audio DAC applications requiring stable component supply across production ramps and long-lifecycle designs.

Supply support for AP7368D-18RS4-7 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 automotive markets.

The AP7368 belongs to Diodes' RF-optimized LDO product line, engineered specifically for noise-sensitive wireless communication subsystems where PSRR, output noise, and fast transient response are critical design parameters.

FAQ

What is the minimum input voltage required for AP7368D-18RS4-7 to maintain 1.8V output at 500mA?

The dropout voltage is 95mV typical at 1.8V/500mA, so minimum input voltage is 1.895V. Per datasheet specifications, the device operates down to 1.7V input, but regulation is guaranteed only when VIN ≥ VOUT + dropout - thus 1.895V is the practical minimum for full-load 1.8V regulation.

Can the LCON pin be left floating, or does it require a defined logic level?

LCON must not be left floating. It requires a defined logic level: pull-up to VDD for 1A mode or pull-down to GND for 500mA mode. Floating LCON may cause undefined current-limit behavior and potential instability due to internal leakage paths and noise susceptibility.

Is the exposed pad (EP) electrically connected, and how should it be handled in PCB layout?

The EP is not electrically connected - it is a thermal pad only. In PCB layout, it must be soldered to a large GND copper pour for thermal dissipation. Do not use it as a functional GND electrode; instead, connect dedicated GND pins (Pin 5) to the same plane to minimize ground loop impedance.

Does AP7368D-18RS4-7 include reverse polarity or reverse current protection?

No. The AP7368D-18RS4-7 lacks integrated reverse-polarity or reverse-current protection. If input reversal or backfeed from output is possible, external protection (e.g., series Schottky diode or ideal diode controller) must be added per application requirements.