Diodes Incorporated ZTX968STOB

Overview

ZTX968STOB from Diodes Incorporated is a PNP silicon planar medium-power high-current transistor rated for −4.5 A continuous collector current, −12 V V_CEO, and 1.2 W power dissipation at T_amb = 25°C, with V_CE(sat) as low as −100 mV at I_C = −2 A / I_B = −50 mA. It operates across −55°C to +200°C and is used in industrial DC-DC converter output stages and high-side switch circuits requiring robust thermal performance.

For engineers reviewing the ZTX968STOB datasheet, ZTX968STOB pinout, ZTX968STOB application, or ZTX968STOB equivalent, key selection criteria include verified PNP polarity, TO-92-compatible E-Line package footprint, guaranteed −20 A peak pulse rating, and h_FE ≥ 300 at I_C = −10 mA - critical for reliable base-drive sizing in switching regulators.

Technical Context

This device is a medium-power discrete PNP bipolar junction transistor optimized for linear and switching operation in high-current, medium-voltage applications. Its design emphasizes low V_CE(sat) (−100 mV typ. at −2 A), high h_FE (450 typ. at −500 mA), and stable gain across temperature (h_FE ≥ 150 at −5 A).

The ZTX968STOB features a rugged silicon planar structure with a maximum junction temperature of +200°C and thermal resistance R_th(j–amb) = 150°C/W on standard PCB mounting. Its f_T of 80 MHz supports fast switching in PWM-driven loads up to several hundred kHz.

Key Specifications

Pinout & Package

Package: E-Line TO-92-compatible plastic case (3-333 outline), lead-form compatible with standard TO-92 sockets and automated insertion equipment. Mounting requires ≥1 inch² copper area for full 1.2 W rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD2955G and ZTX951, the ZTX968STOB uniquely balances TO-92 form factor, −4.5 A capability, and sub-200 mV saturation - making it optimal for compact, medium-power PNP switching where thermal mass and layout density constrain alternatives.

Availability

ZTX968STOB is available at Aetrix Electronics and suitable for industrial DC-DC converters, high-side load switches, and overcurrent protection stages requiring stable component supply, long-lifecycle support, and traceable manufacturing origin.

Supply support for ZTX968STOB 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 Europe.

The ZTX series targets medium-power discrete applications demanding reliability, wide temperature operation, and SPICE-model-supported design - especially in industrial power management and ruggedized control systems.

FAQ

Is ZTX968STOB RoHS compliant and halogen-free?

Yes. ZTX968STOB meets RoHS Directive 2011/65/EU and is certified halogen-free per IEC 61249-2-21. The device uses matte tin-plated leads and green molding compound, with full compliance documentation available through Diodes Incorporated's Quality Portal.

What is the recommended PCB layout for achieving 1.2 W power dissipation?

To achieve the full 1.2 W rating, use ≥1 inch² of 2-ounce copper connected directly to the emitter pad, with thermal vias to inner/ground planes. Avoid narrow traces between pins; maintain ≥0.5 mm clearance to adjacent components for airflow and thermal isolation.

Can ZTX968STOB replace ZTX951 in existing designs?

Only with validation. While both are TO-92 PNP transistors, ZTX968STOB has higher I_C (−4.5 A vs. −2 A) and lower V_CE(sat), but lower V_CEO (−12 V vs. −60 V). Swapping requires checking flyback voltage margins and recalculating base drive for increased h_FE variation.

Does the SPICE model include thermal coupling and temperature-dependent parameters?

Yes. The official Diodes SPICE model for ZTX968STOB includes junction-to-case thermal impedance, temperature-dependent h_FE, V_BE, and saturation characteristics, validated against measured data across −55°C to +150°C. Model files are downloadable from Diodes' website under "Design Resources".