Diodes Incorporated AZ39151D5-ADJTRE1

Overview

AZ39151D5-ADJTRE1 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 is optimized for PC add-in cards and SMPS post-regulation where minimal voltage overhead and low ground current are critical.

For engineers reviewing the AZ39151D5-ADJTRE1 datasheet, AZ39151D5-ADJTRE1 pinout, AZ39151D5-ADJTRE1 application, or AZ39151D5-ADJTRE1 equivalent, key selection criteria include dropout performance at 1.5A, thermal resistance (θ_JA = 100°C/W), adjustable output range, reverse-battery protection, and TO-252-5 package compatibility with high-current PCB layouts.

Technical Context

The AZ39151D5-ADJTRE1 implements a precision bandgap reference and error amplifier driving a PNP pass transistor, enabling fast transient response and stable operation with 10µF ceramic output capacitance. Its internal current and thermal limiting protect against overload and junction overheating up to +125°C.

Reverse-battery and reverse-lead insertion protection are implemented via integrated diode structures on VIN and EN pins, eliminating need for external blocking diodes. The ADJ pin senses feedback from an external resistor divider, setting V_OUT = 1.25V × (1 + R1/R2), with guaranteed regulation across –40°C to +125°C.

Key Specifications

Pinout & Package

Package: TO-252-5 (DPAK-5), thermally enhanced surface-mount package with exposed tab internally connected to GND for improved heat dissipation and EMI shielding.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1826T-ADJE/DC and TPS7A8300RGRT, the AZ39151D5-ADJTRE1 offers balanced performance: superior reverse-protection and accuracy versus Microchip's part, and simpler thermal management and lower BOM cost than TI's QFN solution - making it optimal for mid-tier consumer electronics with space-constrained, high-reliability requirements.

Availability

AZ39151D5-ADJTRE1 is available at Aetrix Electronics and suitable for PC add-in cards, SMPS post-regulators, LCD TV backlight supplies, and set-top box AV processing requiring stable component supply, RoHS-compliant packaging, and tape-and-reel delivery for automated assembly.

Supply support for AZ39151D5-ADJTRE1 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 targets high-current, low-voltage point-of-load regulation, emphasizing ultra-low dropout, thermal resilience, and integrated protection features for space-constrained board-level power design.

FAQ

What is the minimum recommended output capacitor for stable operation?

The datasheet specifies a minimum 10µF ceramic capacitor at the VOUT pin for stability across all operating conditions. Using X5R or X7R dielectrics with ≤100mΩ ESR ensures phase margin remains above 45°, preventing oscillation during load transients. Lower values risk instability, especially with long PCB traces or high ESR electrolytics.

Can the AZ39151D5-ADJTRE1 be used with input voltages below 2.0V?

No. The device requires a minimum input voltage of V_OUT(NOMINAL) + 375mV to maintain regulation. For example, when configured for 1.25V output, VIN must be ≥1.625V. Operation below this threshold places the regulator in dropout, where output voltage tracks VIN minus ~375mV and accuracy degrades beyond ±1%.

Does the NC/ADJ pin require a pull-up or pull-down resistor in fixed-output applications?

No. The NC/ADJ pin is left unconnected in fixed-output versions, but this part (AZ39151D5-ADJTRE1) is the adjustable variant - the pin must be connected to the feedback node of an external resistor divider. Leaving it floating causes undefined output voltage and potential regulation failure.

How does the enable pin behave during power-up sequencing?

The EN pin has hysteresis-free TTL/CMOS thresholds: output enables when V_EN rises above 2.25V and disables when V_EN falls below 0.8V. During slow-rising supply ramps, the regulator activates only after VIN exceeds V_OUT + 375mV and EN crosses its high threshold - ensuring controlled start-up without output overshoot or current surge.