Diodes Incorporated ZTX718STOB

Overview

ZTX718STOB from Diodes Incorporated (formerly Zetex) is a PNP silicon planar medium-power high-gain bipolar junction transistor used as a power MOSFET gate driver in complementary pair configurations with ZTX618. It delivers 2.5 A continuous collector current, -20 V V_CEO, and h_FE ≥ 300 at I_C = -10 mA, supporting robust switching in industrial DC-DC converters and motor control stages.

For engineers reviewing the ZTX718STOB datasheet, ZTX718STOB pinout, ZTX718STOB application, or ZTX718STOB equivalent, key selection criteria include verified V_CE(sat) ≤ -145 mV at I_C = -1.5 A/I_B = -50 mA, f_T = 150 MHz, safe operating area up to -6 A pulsed, thermal resistance R_th(j–amb) = 116 °C/W on 1 in² PCB copper, and TO-92 compatible E-line package compatibility.

Technical Context

The ZTX718STOB operates as a medium-power PNP BJT optimized for fast-switching gate drive applications. Its design emphasizes low V_CE(sat) (-145 mV typical at I_C = -1.5 A), high h_FE (up to 475 at I_C = -10 mA), and stable gain across 10 mA–6 A pulsed range - enabling efficient current sourcing into MOSFET gates without external amplification.

Thermal performance is defined by two R_th(j–amb) ratings: 175 °C/W (free air) and 116 °C/W (1 in² PCB copper), confirming its reliance on board-level copper for sustained 1 W dissipation. The device supports operation from -55 °C to +200 °C junction temperature, with breakdown voltages rated at -20 V V_CEO, -20 V V_CBO, and -5 V V_EBO.

Key Specifications

Pinout & Package

Package: TO-92 compatible E-line plastic package with standard lead configuration (Emitter-Base-Collector, left-to-right when flat side faces viewer).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP medium-power BJT applications.

Compared with MJD2955G and BCP53-16, ZTX718STOB uniquely balances high h_FE, low V_CE(sat), and TO-92 compatibility - making it optimal for cost-sensitive, fast-switching gate drive where thermal budget is managed via PCB copper, not heatsinks.

Availability

ZTX718STOB is available at Aetrix Electronics and suitable for motor control gate drivers, DC-DC converter PWM stages, and industrial PLC output modules requiring stable component supply, long-lifecycle availability, and consistent parametric performance across production batches.

Supply support for ZTX718STOB 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 acquired Zetex Semiconductors in 2008 and maintains its portfolio of high-performance discrete transistors and analog ICs for industrial, automotive, and computing markets.

The ZTX series was developed specifically for high-reliability, medium-power switching applications demanding predictable gain, low saturation voltage, and rugged thermal behavior in compact through-hole packages.

FAQ

What is the maximum safe pulsed collector current for ZTX718STOB?

The absolute maximum pulsed collector current (I_CM) is -6 A, measured under pulsed conditions with 300 µs pulse width and ≤2% duty cycle. This rating assumes proper PCB copper area (≥1 in²) and ambient temperature ≤25 °C. Exceeding this value risks second breakdown or bond wire failure.

Can ZTX718STOB be used in place of ZTX718 without modification?

Yes - ZTX718STOB is a direct replacement for ZTX718, sharing identical electrical specifications, TO-92 E-line pinout (E-B-C), and thermal characteristics. The "STOB" suffix denotes tape-and-reel packaging per Diodes Incorporated's current ordering nomenclature; no circuit or layout changes are needed.

Is ZTX718STOB suitable for linear regulator applications?

No - while it can operate in linear mode, ZTX718STOB is optimized for switching use with specified t_on/t_off, safe operating area curves, and pulsed current ratings. Its low V_CE(sat) and high h_FE do not compensate for lack of SOA derating data for continuous linear operation above 500 mW.

What is the recommended minimum PCB copper area for 1 W continuous operation?

For 1 W continuous power dissipation at T_amb = 25 °C, the datasheet specifies a minimum 1 in² (6.45 cm²) copper area on the PCB. This achieves the 116 °C/W R_th(j–amb) rating. Reducing copper area increases junction temperature proportionally and requires derating per the published thermal curve.