Diodes Incorporated ZTX758STOB

Overview

ZTX758STOB from Diodes Incorporated is a PNP medium-power high-voltage transistor in E-Line (TO-92 compatible) package, rated for -400V V_CEO, -0.5A continuous collector current, and 1W power dissipation at +25°C ambient. It operates up to +200°C junction temperature and features low saturation voltage of -250mV at -50mA/-5mA drive, supporting high-reliability industrial switching and flyback converter applications.

For engineers reviewing the ZTX758STOB datasheet, ZTX758STOB pinout, ZTX758STOB application, or ZTX758STOB equivalent, key selection criteria include verified -400V breakdown rating, AEC-Q101 qualification, thermal resistance of 175°C/W (min pad layout), and confirmed E-Line mechanical compatibility with TO-92 footprints.

Technical Context

This PNP bipolar junction transistor is optimized for high-voltage linear and switching operation in demanding environments. Its -400V V_CEO and -400V V_CBO ratings enable use in off-line AC/DC primary-side circuits and relay drivers requiring robust voltage blocking. The device delivers h_FE = 50 at -1mA and drops to 40 at -200mA, supporting stable gain across its operating range.

Thermal design is enabled by dual derating profiles: 1.5W at 116°C/W (25mm² copper pad) and 1W at 175°C/W (minimum pad). Turn-on time is 140ns and turn-off time is 2000ns under specified pulse conditions, indicating suitability for moderate-speed switching below 100kHz.

Key Specifications

Pinout & Package

E-Line (TO-92 compatible) plastic package with matte tin-plated leads; 0.159g weight; UL 94V-0 flammability rating; flat face marking "ZTX758", rounded face marking "C E B".

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZTX757, ZTX758STOB provides 100V higher blocking capability critical for universal-input power supplies; versus MJD2955T4G, it trades current capacity for compact E-Line packaging and superior voltage resilience in space-constrained designs.

Availability

ZTX758STOB is available at Aetrix Electronics and suitable for industrial relay drivers, flyback converter switches, high-voltage linear regulators, and automotive body control modules requiring stable component supply across extended temperature and voltage ranges.

Supply support for ZTX758STOB 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 and manufacturing operations across Asia and the Americas.

The ZTX series targets high-reliability medium-power bipolar transistors for industrial, automotive, and power conversion applications where voltage resilience, thermal robustness, and AEC-Q101 compliance are essential.

FAQ

What is the correct pinout orientation for ZTX758STOB when viewed from the flat face?

When viewing the flat face with the leads pointing downward and the marking "ZTX758" visible, the left-to-right pin order is Emitter (E), Collector (C), Base (B). This matches the official Diodes Incorporated pin-out diagram and differs from standard TO-92 PNP orientation, requiring verification before PCB layout.

Does ZTX758STOB support operation above 150°C ambient temperature?

Yes - ZTX758STOB is rated for junction temperatures up to +200°C and has an operating storage range of -55°C to +200°C. At 100°C ambient, it can dissipate ~0.57W (derated from 1W using 175°C/W R_θJA), making it suitable for under-hood automotive or enclosed industrial environments.

Is ZTX758STOB pin-compatible with legacy TO-92 PNP transistors like BC557?

No - although packaged in E-Line (TO-92 compatible), ZTX758STOB uses E-C-B pinout (flat face view), whereas BC557 uses E-B-C. Direct replacement would cause circuit failure due to reversed collector/emitter connections; PCB layout and schematic must be updated accordingly.

What is the minimum base current required to saturate ZTX758STOB at I_C = -100mA?

Per datasheet, V_CE(sat) = -500mV is guaranteed at I_C = -100mA with I_B = -10mA. To ensure reliable saturation across process variation and temperature, a design target of I_B ≥ -15mA is recommended, corresponding to h_FE(sat) ≈ 6.7 under those conditions.