Diodes Incorporated AZ39151D5-ADJTRG1

Overview

AZ39151D5-ADJTRG1 from Diodes Incorporated is an adjustable 1.5A ultra-low dropout linear regulator with ±1% output voltage accuracy, 375mV dropout at full load, and TTL/CMOS-compatible enable control. It operates from 1.25V to 13.5V input, delivers stable output down to 1.25V via external resistor divider, and features reversed-battery protection and thermal shutdown-used in PC add-in cards requiring tight regulation under high-current, low-voltage conditions.

For engineers reviewing the AZ39151D5-ADJTRG1 datasheet, AZ39151D5-ADJTRG1 pinout, AZ39151D5-ADJTRG1 application, or AZ39151D5-ADJTRG1 equivalent, key selection criteria include dropout performance at 1.5A, ground current vs. load/junction temperature, ADJ-pin biasing requirements, and TO-252-5 thermal resistance (θ_JA = 100°C/W) for board-level thermal design.

Technical Context

The AZ39151D5-ADJTRG1 implements a PMOS pass transistor architecture enabling ultra-low dropout and fast transient response. Its internal reference is trimmed to ±1% over –40°C to +125°C, and the ADJ pin senses feedback directly from the output node through an external resistive divider.

Protection circuitry includes thermal foldback, current limiting (~2.8A short-circuit), reversed-battery tolerance, and enable-controlled shutdown with <220µA standby current. Ground current remains below 34mA at 1.5A load and varies predictably with junction temperature and VIN–VOUT differential.

Key Specifications

Pinout & Package

Package: TO-252-5 (DPAK-5), thermally enhanced surface-mount package with exposed tab internally connected to GND (Pin 3). Dimensions: 6.65 × 9.90 × 1.27 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1826T-ADJ/DC and TLS850F2TE/V33, the AZ39151D5-ADJTRG1 uniquely combines ultra-low dropout, ±1% accuracy, reversed-battery tolerance, and ADJ flexibility in a single TO-252-5 package-making it optimal for cost-sensitive, high-reliability consumer electronics where input voltage margin is constrained.

Availability

AZ39151D5-ADJTRG1 is available at Aetrix Electronics and suitable for PC add-in card power, SMPS post-regulation, LCD TV logic supplies, and set-top box USB hub regulation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AZ39151D5-ADJTRG1 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-efficiency power management, signal integrity, and protection solutions for consumer, industrial, and computing markets.

The AZ39151 series belongs to Diodes' precision LDO portfolio, engineered specifically for high-current, low-voltage applications where minimal dropout, tight accuracy, and robust fault protection are non-negotiable-such as PC expansion cards and digital video equipment.

FAQ

What is the minimum recommended output capacitor for stable operation?

The datasheet specifies a minimum 10µF ceramic output capacitor with ≤10mΩ ESR for stability across all loads and temperatures. Using lower capacitance or higher-ESR types may cause oscillation or degraded transient response, especially above 1A load steps. X5R or X7R dielectrics are preferred for temperature stability.

Can the ADJ pin be left floating in fixed-output configurations?

No-the ADJ pin must be connected to VOUT in fixed-output versions (e.g., AZ39151D5-3.3TRG1), but for the AZ39151D5-ADJTRG1, it must be externally biased via a resistor divider to set V_OUT. Leaving ADJ floating causes undefined regulation and potential output collapse due to lack of feedback path.

How does thermal performance change with PCB copper area?

θ_JA drops from 100°C/W (standard JEDEC 2S2P test board) to ~45°C/W with ≥400mm² of 2oz copper connected to the exposed tab. This allows full 1.5A operation up to 85°C ambient-verified in Diodes' thermal characterization report DS41513 Rev. 2, page 9.

Is the enable pin internally pulled down when not driven?

No-EN has no internal pull-down. When left open, the input leakage (<4µA) and CMOS threshold ensure reliable shutdown, but for deterministic behavior in noisy environments, a 100kΩ pull-down to GND is recommended per Diodes' layout guidelines in section 8.2 of DS41513.