Diodes Incorporated ZTX757STOA

Overview

ZTX757STOA from Diodes Incorporated is a PNP silicon planar medium-power high-voltage bipolar junction transistor (BJT) designed for switching and linear amplification in high-voltage DC-DC converters, relay drivers, and industrial control interfaces. It features −300 V V_CEO, −0.5 A continuous collector current, 1 W power dissipation at 25°C, and h_FE ≥ 40 at −100 mA/−5 V, operating reliably from −55°C to +200°C.

For engineers reviewing the ZTX757STOA datasheet, ZTX757STOA pinout, ZTX757STOA application, or ZTX757STOA equivalent, key selection criteria include verified −300 V breakdown rating, saturation voltage under defined drive conditions (V_CE(sat) ≤ −0.5 V @ −100 mA/−10 mA), thermal capability up to +200°C junction temperature, and TO-92 compatible mechanical footprint for legacy board replacement.

Technical Context

This PNP BJT operates with emitter-grounded configuration in common-emitter mode, supporting high-voltage off-state blocking while delivering controlled current gain across −10 mA to −100 mA collector loads. Its f_T of 30 MHz enables moderate-speed switching (t_r/t_f < 1.2 µs @ IC/IB = 10), and C_obo of 20 pF ensures predictable Miller effect behavior in inductive load circuits.

The device uses planar epitaxial construction with gold-doped base region for improved ruggedness and consistent V_(BR)CEO performance. Safe operating area (SOA) curves confirm single-pulse capability up to 300 V × 1 A with 1 ms pulse width, making it suitable for transient-tolerant industrial power stage designs.

Key Specifications

Pinout & Package

Package: TO-92 (E-Line compatible), through-hole, 3-lead plastic package with standard lead spacing and orientation per JEDEC TO-92 outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZTX757STOA, ZTX756STOA trades 100 V headroom for identical cost and form factor, while MJD2955G offers tenfold current capacity at the expense of voltage rating and switching speed-making ZTX757STOA uniquely balanced for medium-current, high-voltage discrete control where TO-92 fit and thermal envelope are constraints.

Availability

ZTX757STOA is available at Aetrix Electronics and suitable for industrial relay drivers, high-voltage DC-DC converters, and automotive HVAC blower control requiring stable component supply and long-term obsolescence resilience.

Supply support for ZTX757STOA 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, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and Malaysia.

The ZTX series targets high-reliability discrete power switching applications, emphasizing voltage robustness, thermal endurance, and legacy footprint compatibility for industrial and automotive subsystems.

FAQ

What is the maximum safe operating voltage for ZTX757STOA in continuous DC applications?

The absolute maximum V_CEO is −300 V, but design practice recommends limiting continuous V_CE to ≤ −240 V to maintain 20% voltage derating margin per IEC 61000-4-5 surge immunity guidelines. At −240 V and −0.5 A, power dissipation remains within the 1 W rating only with adequate heatsinking and ambient below 60°C.

Can ZTX757STOA replace ZTX756STOA without circuit modification?

Yes-ZTX757STOA is pin- and footprint-compatible with ZTX756STOA and shares identical base-emitter and saturation characteristics. However, its −300 V V_CEO allows operation in higher-voltage rails where ZTX756 would risk avalanche breakdown; no schematic or layout changes are needed for drop-in substitution.

What base drive current is required to ensure full saturation at −0.5 A collector current?

With h_FE ≥ 40 at −100 mA and conservatively assuming h_FE = 30 at −500 mA, a base current of −16.7 mA is required for forced β = 30. Using a standard −5 V logic source and 300 Ω base resistor delivers −16.7 mA, ensuring V_CE(sat) stays ≤ −0.5 V with margin.

Is ZTX757STOA suitable for use in Class B audio amplifier output stages?

No-its f_T of 30 MHz and SOA limitations make it unsuitable for linear Class B operation above a few hundred kHz. The device is optimized for switching and pulsed linear modes (e.g., PWM-driven loads), not wideband analog amplification; distortion and thermal instability would occur above 20 kHz with reactive loads.