Diodes Incorporated ZXTR2005ZQ-13

Overview

ZXTR2005ZQ from Diodes Incorporated is a monolithic high-voltage linear regulator integrating an emitter-follower transistor, Zener reference, and 150kΩ current-limiting resistor in a single SOT89 package. It delivers a regulated 5V ±10% output at up to 30mA across 10–100V input, with 45dB PSRR and -40°C to +125°C operating junction range. Used for startup bias in PoE-powered DC-DC converters.

For engineers reviewing the ZXTR2005ZQ datasheet, ZXTR2005ZQ pinout, ZXTR2005ZQ application, or ZXTR2005ZQ equivalent, key selection criteria include its 100V absolute max input rating, integrated quiescent current limiting, thermal resistance of 59°C/W (on 50mm×50mm copper), AEC-Q101 qualification, and SOT89 footprint compatibility with high-voltage auxiliary supply designs.

Technical Context

The ZXTR2005ZQ implements a series linear regulation architecture using an emitter-follower pass transistor driven by an internal Zener-referenced shunt regulator. Regulation is achieved without external feedback components - the 150kΩ internal resistor sets base current and defines quiescent draw.

It operates across a 10V–100V input range while maintaining 5V output within ±10% tolerance, with line regulation of ≤300mV over VIN = 10–72V and load regulation of ≤-400mV from 0.1mA to 100mA. Thermal protection relies on junction-to-ambient dissipation limits (1.7W max) and derating above +25°C ambient.

Key Specifications

Pinout & Package

Package: SOT89 - surface-mount plastic package with exposed VIN pad for thermal conduction; 3-pin outline, 4.5mm × 2.5mm footprint, 1.05mm nominal height.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage linear regulator applications.

Compared with TL783CP and LR8N3G, the ZXTR2005ZQ uniquely combines fixed 5V output, integrated biasing, SOT89 thermal efficiency, and AEC-Q101 compliance - making it optimal for space-constrained, automotive-grade PoE and telecom auxiliary supplies where component count and qualification matter.

Availability

ZXTR2005ZQ-13 is available at Aetrix Electronics and suitable for Power-over-Ethernet (PoE) injectors, telecom line cards, and automotive body control modules requiring stable component supply across extended temperature and high-voltage stress conditions.

Supply support for ZXTR2005ZQ-13 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 communications markets.

The ZXTR2005ZQ belongs to Diodes' high-voltage linear regulator product line, designed specifically to replace multi-component discrete bias networks in PoE, telecom, and automotive auxiliary power applications where simplicity, qualification, and thermal efficiency are critical.

FAQ

What is the minimum input voltage required for regulation?

The ZXTR2005ZQ requires a minimum input voltage of 10V to maintain regulated 5V output. Below 10V, VOUT follows VIN minus ~1.5V (i.e., VOUT ≈ VIN – 1.5V). This threshold is defined by the internal Zener reference and emitter-follower headroom, and is confirmed in the datasheet's "Minimum Value of Input Voltage Required to Maintain Line Regulation" specification.

Can ZXTR2005ZQ drive a 30mA load continuously at 100V input?

No - at VIN = 100V and IOUT = 30mA, power dissipation would be (100V – 5V) × 30mA = 2.85W, exceeding the device's 1.7W maximum rating. Continuous operation at 100V requires IOUT ≤ 17.9mA (1.7W ÷ 95V) on a 50mm×50mm copper pad; derating applies above +25°C ambient per the published curve.

Is an output capacitor required, and what value is recommended?

Yes - a minimum 10µF tantalum or ceramic capacitor is required between VOUT and GND to ensure stability and transient response. The datasheet specifies this for regulation maintenance and recommends adding a 1µF ceramic capacitor at VIN for high-frequency noise suppression. Without the 10µF output cap, output may oscillate or fail to regulate under load steps.

Does the ZXTR2005ZQ require a minimum load current?

Yes - the device requires a minimum load of 10µA on VOUT to maintain regulation. This is due to internal Zener current requirements and emitter-follower biasing. Applications with intermittent or zero-load states (e.g., deep sleep modes) must include a bleed resistor or active load to meet this requirement, as confirmed in the "Typical Application Circuit" section.