Diodes Incorporated ZXTR2012Z-7

Overview

ZXTR2012Z-7 from Diodes Incorporated is a monolithic high-voltage linear regulator transistor integrating an emitter-follower transistor, 12V Zener reference, and 150kΩ current-limiting resistor in a single SOT89 package. It delivers a regulated 12V ±10% output at up to 30mA with input voltage range of 15V–100V, and is used as startup bias supply in isolated DC-DC converters.

For engineers reviewing the ZXTR2012Z-7 datasheet, ZXTR2012Z-7 pinout, ZXTR2012Z-7 application, or ZXTR2012Z-7 equivalent, key selection criteria include its 100V absolute max input rating, integrated quiescent current limiting, thermal performance on 15mm² copper, and compatibility with PoE auxiliary power rails requiring robust startup regulation under wide VIN transients.

Technical Context

The ZXTR2012Z-7 implements a series linear regulator using an emitter-follower topology with internal Zener-based reference and fixed 150kΩ base resistor. Regulation occurs only when VIN ≥ 15V; below that, VOUT follows VIN minus ~1.5V saturation drop.

It operates across -40°C to +125°C junction temperature, with thermal resistance RθJA = 112°C/W on minimal 15mm² copper and RθJC = 15.7°C/W to case. Safe operating area supports 47mA continuous output at VIN = 48V and 880mA pulsed (100µs) at same input.

Key Specifications

Pinout & Package

Package: SOT89 - surface-mount plastic package with exposed VIN pad for thermal conduction; dimensions 4.5 × 2.5 × 1.5 mm; RoHS-compliant matte tin plating; weight 0.052 g.

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 ZXTR2012Z-7 uniquely balances fixed 12V regulation, 47mA output, 150kΩ self-biasing, and SOT89 thermal performance - making it optimal for cost-sensitive, space-constrained startup supplies in PoE and telecom where 30mA load and 100V surge tolerance are primary requirements.

Availability

ZXTR2012Z-7 is available at Aetrix Electronics and suitable for Power over Ethernet (PoE), telecommunications infrastructure, and industrial DC-DC converter startup applications requiring stable component supply, long-lifecycle availability, and AEC-Q101 reliability validation.

Supply support for ZXTR2012Z-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 industrial, automotive, and communications markets.

The ZXTR2012Z-7 belongs to Diodes' high-voltage linear regulator transistor family, designed specifically to replace multi-component discrete bias networks in HV startup and auxiliary supply circuits where space, reliability, and surge immunity are critical.

FAQ

What is the minimum input voltage required for regulation?

The ZXTR2012Z-7 requires VIN ≥ 15V to maintain regulated 12V output. Below 15V, VOUT tracks VIN minus ~1.5V saturation drop. This threshold is defined by internal Zener and transistor VBE characteristics, not adjustable externally. Operation at VIN < 15V yields unregulated output but remains within absolute maximum ratings.

Can ZXTR2012Z-7 be used with negative input supplies like –48V telecom rails?

Yes - the device functions with VIN referenced to GND, so a –48V rail can be applied to VIN with GND tied to –48V system ground, yielding +12V relative to that reference. The internal structure tolerates reverse polarity on VOUT, but VOUT must not exceed VIN + 12V or 18V absolute. Proper grounding and decoupling are essential.

What capacitor values are recommended on VIN and VOUT pins?

A 1µF ceramic capacitor is recommended between VIN and GND to suppress high-frequency noise and transient spikes. A minimum 10µF low-ESR electrolytic or tantalum capacitor is required between VOUT and GND to ensure stability and transient response; smaller ceramics (<100nF) may be added in parallel for high-frequency filtering.

Is external current limiting needed for short-circuit protection?

No - the internal 150kΩ resistor limits base current, inherently restricting output current to safe levels under short-circuit conditions. At VIN = 48V, maximum theoretical short-circuit current is ~320µA (48V / 150kΩ), well below destructive thresholds. No external foldback or shutdown circuitry is required.