Diodes Incorporated ZTX576

Overview

ZTX576 from Zetex Semiconductors (now Diodes Incorporated) is a PNP silicon planar medium-power high-voltage transistor with V_CEO = −200 V, I_C = −1 A continuous, P_tot = 1 W at T_amb = 25°C, and f_T = 100 MHz - used in high-voltage DC-DC converter switching stages and industrial relay drivers.

For engineers reviewing the ZTX576 datasheet, ZTX576 pinout, ZTX576 application, or ZTX576 equivalent, key selection considerations include its −200 V V_CEO rating, −1 A I_C capability, TO-92-compatible E-Line package, h_FE range of 50–300 at −10 mA, and verified switching performance under pulsed conditions (300 µs, ≤2% duty cycle).

Technical Context

The ZTX576 is a discrete PNP bipolar junction transistor optimized for medium-power linear and switching applications requiring high breakdown voltage and stable gain across collector currents from −10 mA to −300 mA. Its h_FE maintains ≥50 at −10 mA and remains usable up to −300 mA, with V_CE(sat) = −0.3 V at −100 mA/−10 mA drive.

Designed for operation up to +200°C junction temperature, it supports robust thermal cycling in industrial controls. The device exhibits f_T = 100 MHz at −50 mA and −10 V, confirming suitability for moderate-speed switching (e.g., <500 kHz PWM), with documented turn-on/off times in the nanosecond-to-microsecond range under defined pulse conditions.

Key Specifications

Pinout & Package

Package: E-Line TO-92 compatible (3-lead plastic package, lead pitch 1.27 mm, body height ~4.5 mm). Pin identification follows standard TO-92 orientation: viewing flat side with leads down, left-to-right is Emitter (E), Base (B), Collector (C).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP high-voltage switching transistor applications.

Compared with BCV61 and BD139, the ZTX576 uniquely balances −200 V breakdown, −1 A current, TO-92 compatibility, and 100 MHz f_T, making it optimal for compact, high-voltage switching where both voltage margin and moderate speed are required.

Availability

ZTX576 is available at Aetrix Electronics and suitable for industrial relay drivers, high-voltage DC-DC converters, motor control interfaces, and overvoltage protection circuits requiring stable component supply and long-term manufacturability.

Supply support for ZTX576 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

Zetex Semiconductors, acquired by Diodes Incorporated in 2008, specialized in high-performance discrete semiconductors for industrial, automotive, and power management applications.

The ZTX series was developed specifically for medium-power, high-voltage bipolar switching and amplification tasks where TO-92 compatibility, guaranteed gain, and rugged voltage ratings were critical - especially in legacy industrial control designs.

FAQ

Is ZTX576 RoHS compliant?

Yes, ZTX576 is RoHS compliant per Diodes Incorporated's product change notice PCN-2012-001, which confirmed lead-free termination and halogen-free molding compound for all ZTX-series devices manufactured after Q2 2012. Legacy date codes may reflect pre-RoHS production, but current stock meets RoHS 2011/65/EU requirements.

Can ZTX576 replace ZTX550 in existing designs?

No - ZTX550 is an NPN transistor (V_CEO = +150 V), while ZTX576 is PNP (V_CEO = −200 V). Their polarity, biasing, and circuit topology are incompatible. Direct replacement would require schematic-level redesign, including inversion of supply connections and base drive logic.

What is the maximum safe continuous collector current at 70°C ambient?

At T_amb = 70°C, derating begins at 11.4 mW/°C above 25°C. With 1 W P_tot at 25°C, maximum allowable power at 70°C is 0.543 W. Using V_CE(sat) ≈ −0.35 V at −500 mA, max continuous I_C is approximately −650 mA - confirmed by Safe Operating Area curves in the original Zetex datasheet ZTX576 3-205.

Does ZTX576 support avalanche energy rating?

No - the ZTX576 datasheet does not specify single-pulse avalanche energy (E_AS) or repetitive avalanche ratings. It is not characterized or guaranteed for unclamped inductive switching. Designers must implement external clamping (e.g., TVS diode or RCD snubber) when switching inductive loads to avoid secondary breakdown.