Diodes Incorporated AP7315DQ-18W5-7

Overview

AP7315DQ-18W5-7 from Diodes Incorporated is an automotive-grade 150mA low-dropout linear regulator with fixed 1.8V output, integrated output discharge function, ±1% output voltage accuracy, 75dB PSRR at 1kHz, and 60µV_rms output noise (10Hz–100kHz). It operates from 1.7V to 5.25V input, supports -40°C to +125°C ambient, and is AEC-Q100 Grade 1 qualified in SOT25 for noise-sensitive automotive power rails.

For engineers reviewing the AP7315DQ-18W5-7 datasheet, AP7315DQ-18W5-7 pinout, AP7315DQ-18W5-7 application, or AP7315DQ-18W5-7 equivalent, this LDO delivers high PSRR, ultra-low quiescent current (35µA typ), fast load transient response, and controlled output discharge-key for automotive infotainment, ADAS POL, RF supply sequencing, and camera sensor biasing where rail stability and shutdown behavior are critical.

Technical Context

The AP7315DQ-18W5-7 uses a CMOS-based LDO architecture with internal N-channel pass transistor and precision bandgap reference. Its enable-controlled operation supports active-high logic (EN threshold: 1.3V min high, 0.5V max low) and includes fold-back short-circuit protection limiting output current to ~55mA during VOUT-to-GND fault.

Unlike the non-discharge AP7315Q variant, the 'D' suffix indicates integrated auto-discharge circuitry (30Ω typical on-resistance) that actively pulls VOUT to GND when EN = low, ensuring rapid output decay and preventing back-powering of downstream circuitry-a requirement in automotive power sequencing and safety-critical shutdown paths.

Key Specifications

Pinout & Package

SOT25 (5-pin small-outline transistor) package with matte tin-plated leads, moisture sensitivity level 1 per J-STD-020, and 0.016g mass. Thermal resistance θ_JA = 179°C/W on JEDEC High-K board.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP7315Q-18W5-7, the AP7315DQ-18W5-7 adds essential discharge functionality for automotive shutdown compliance, while TLD1115DQ-18W5-7 trades off noise performance (85µV_rms) for current monitoring-making the AP7315DQ optimal for noise-sensitive, sequence-critical 1.8V rails.

Availability

AP7315DQ-18W5-7 is available at Aetrix Electronics and suitable for automotive infotainment power supplies, ADAS camera POL rails, RF module biasing, and wireless communication transceiver applications requiring stable component supply across extended temperature and AEC-Q100-compliant production cycles.

Supply support for AP7315DQ-18W5-7 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-reliability power management, signal integrity, and protection solutions for automotive, industrial, and consumer markets.

The AP7315Q/DQ series belongs to Diodes' automotive-qualified LDO portfolio, designed specifically to meet stringent AEC-Q100 Grade 1 requirements for noise-sensitive, always-on, and safety-related power rails in modern vehicles.

FAQ

What is the purpose of the NC pin (Pin 4) on AP7315DQ-18W5-7?

Pin 4 is a no-connect terminal with no internal bond wire or circuit connection. It must remain unconnected-neither tied to GND nor left floating in a way that risks solder bridging. This design choice simplifies die layout and improves yield without affecting electrical performance or thermal characteristics in the SOT25 package.

How does the output discharge function behave during EN deactivation?

When EN is pulled low (<0.5V), the internal 30Ω N-channel FET connects VOUT to GND, discharging external output capacitance. For a 1µF capacitor, VOUT falls from 1.8V to <100mV in <100µs. Discharge current is limited by the FET's on-resistance and does not trigger overcurrent protection, ensuring safe, repeatable shutdown without external components.

Can AP7315DQ-18W5-7 be used with input voltages below 1.8V?

No. The minimum input voltage is 1.7V, but dropout voltage at 150mA is 0.34V-so VIN must be ≥2.14V to maintain regulation at full load. At light loads (<1mA), it can regulate down to VIN = 1.7V, but output accuracy degrades near dropout. For sub-1.8V inputs, a different LDO or buck converter is required.

Is the 60µV_rms output noise measured under load?

Yes-the 60µV_rms noise specification is measured at I_OUT = 30mA, BW = 10Hz–100kHz, with 0.47µF ceramic input/output capacitors. Noise increases slightly at higher loads (e.g., 65µV_rms at 150mA) due to pass transistor thermal effects, but remains within 10% of nominal across full operating range.