Diodes Incorporated ZXTR2012K-13

Overview

ZXTR2012K from Diodes Incorporated is a monolithic high-voltage linear regulator transistor integrating a zener diode, emitter-follower transistor, and 150kΩ current-limiting resistor in a single TO252-3L (DPAK) package. It delivers a nominal 12V ±10% regulated output at up to 15mA continuous load, supports input voltages from 15V to 100V, and is engineered for startup supply regulation in PoE-powered DC-DC converters.

For engineers reviewing the ZXTR2012K datasheet, ZXTR2012K pinout, ZXTR2012K application, or ZXTR2012K equivalent, key selection criteria include its 100V absolute max input rating, integrated 150kΩ bias resistor, 12V output tolerance, thermal resistance of 44°C/W (on 50mm×50mm copper), and AEC-Q101 qualification for automotive-grade reliability.

Technical Context

The ZXTR2012K implements a series linear regulator using an emitter-follower topology with internal zener-based reference and fixed 150kΩ base-bias resistor - eliminating external components required by discrete solutions. Its regulation mechanism relies on V_BE tracking and zener voltage stability across temperature.

It operates within a -40°C to +125°C junction temperature range, features 4000V HBM ESD robustness, and maintains regulation only when input voltage stays between 15V and 100V; below 15V, output follows VIN minus ~1.5V. Output requires ≥10µA minimum load and 10µF bypass capacitance for stability.

Key Specifications

Pinout & Package

Package: TO252-3L (DPAK), surface-mount, with exposed VIN pad for thermal conduction and mechanical anchoring. Molded green compound, matte tin-plated leads, UL 94V-0 rated.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZXTR2012K, ZXTR2008K offers identical integration and reliability at 8V output, while TL783CP trades simplicity and qualification for flexibility - making ZXTR2012K optimal for fixed 12V PoE and telecom applications demanding minimal BOM and automotive-grade robustness.

Availability

ZXTR2012K is available at Aetrix Electronics and suitable for Power-over-Ethernet (PoE) startup supplies, telecom line card biasing, and industrial DC-DC auxiliary power rails requiring stable component supply, long-term lifecycle assurance, and AEC-Q101-compliant reliability.

Supply support for ZXTR2012K 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 devices for industrial, automotive, and communications markets.

The ZXTR series targets high-voltage linear regulation in space-constrained, thermally demanding applications - designed specifically to replace multi-component discrete regulators in PoE, telecom, and industrial power subsystems.

FAQ

What is the minimum load required for stable regulation?

The ZXTR2012K requires a minimum load of 10µA on VOUT to maintain regulation. Below this threshold, output voltage may rise above 12V due to insufficient base current for the internal transistor. A 10µF ceramic capacitor to GND is also mandatory for transient stability and noise suppression.

Can ZXTR2012K operate with input voltages below 15V?

Yes, but regulation is lost below 15V input. When VIN < 15V, VOUT follows VIN minus approximately 1.5V (V_BE drop), behaving as a simple emitter follower. For regulated 12V output, VIN must remain within 15V to 100V per datasheet specifications.

How does the internal 150kΩ resistor affect design?

The integrated 150kΩ resistor sets the base bias current, determining quiescent current (240–590 µA). This eliminates external bias components, simplifies layout, and ensures predictable startup behavior directly from 48V PoE inputs - no scaling resistors or voltage dividers are needed.

Is thermal pad connection mandatory for rated power handling?

Yes. The exposed VIN pad is electrically and thermally connected to the input terminal. To achieve the rated 2.3W power dissipation and 44°C/W R_θJA, it must be soldered to ≥50mm² of 1oz copper on a single-sided FR4 PCB. Without this, thermal resistance rises to 90°C/W, severely limiting usable output current.