Diodes Incorporated ZTX560STOB

Overview

ZTX560STOB from Zetex Semiconductors is a PNP silicon planar high-voltage transistor rated for V_CEO = −500 V, V_CBO = −500 V, and continuous I_C = −150 mA, with h_FE = 100–300 (at I_C = −1 mA to −100 mA), V_CE(sat) = −0.2 V to −0.5 V, and f_T = 60 MHz - used in high-voltage DC-DC converter switching stages.

For engineers reviewing the ZTX560STOB datasheet, ZTX560STOB pinout, ZTX560STOB application, or ZTX560STOB equivalent, key selection criteria include verified high-voltage blocking capability, low saturation voltage under pulsed load conditions, h_FE consistency across collector current range, and TO-92 compatible leadframe geometry.

Technical Context

This PNP bipolar junction transistor employs a planar silicon structure optimized for high-voltage breakdown stability and controlled minority-carrier lifetime. Its V_BR(CEO) and V_BR(CBO) are both rated at −500 V under specified test conditions (I_C = −10 mA and −100 µA respectively), confirming symmetrical high-voltage tolerance.

Switching performance is characterized by t_on = 110 ns and t_off = 1.5 µs under V_CE = −100 V, I_C = −50 mA, and base drive of −5 mA / +10 mA pulses, with C_obo = 8 pF at V_CB = −20 V - indicating suitability for medium-frequency hard-switched topologies.

Key Specifications

Pinout & Package

Package: TO-92 (plastic, 3-lead, through-hole). Dimensions conform to standard TO-92 outline: body height 4.37–4.77 mm, lead pitch 2.16–2.41 mm, lead length ≥13.00 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZTX550STOB and MPSA92, ZTX560STOB delivers the highest voltage rating (−500 V), lowest V_CE(sat), and widest h_FE range - making it the sole option for new 400–500 V discrete PNP switching or linear regulation designs requiring single-device implementation.

Availability

ZTX560STOB is available at Aetrix Electronics and suitable for industrial HV power supplies, capacitor discharge ignition modules, photomultiplier tube bias circuits, and electrostatic precipitator drivers requiring stable component supply and long-term obsolescence management.

Supply support for ZTX560STOB 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 plc (now part of Diodes Incorporated) was a UK-based designer of high-performance analog and discrete semiconductors, focused on precision, high-voltage, and high-speed devices.

ZTX560STOB belongs to the ZTX series of high-voltage bipolar transistors engineered specifically for robustness in industrial power conversion, ignition, and scientific instrumentation where reliability under sustained high-voltage stress is critical.

FAQ

What is the maximum allowable junction temperature for ZTX560STOB?

The ZTX560STOB has an absolute maximum junction temperature (T_j) of +150°C, with storage temperature range extending from −55°C to +150°C. Derating of P_tot = 1 W begins above 25°C ambient per the thermal resistance curve in the original datasheet; heatsinking is recommended for sustained I_C > 100 mA at elevated ambient temperatures.

Is ZTX560STOB suitable for linear regulator applications?

Yes - its −500 V V_CEO, low −0.2 V V_CE(sat) at moderate current, and stable h_FE across I_C = −1 mA to −100 mA make it appropriate for negative-output linear regulators and HV pre-regulators. Thermal design must account for P_D = V_CE × I_C, especially when dropping >200 V at >50 mA.

Does ZTX560STOB have a documented avalanche rating?

No official avalanche energy (E_AS) or ruggedness rating is published in the Zetex ZTX560 datasheet. The device is characterized for safe operating area (SOA) under DC and pulsed conditions up to I_CM = −500 mA, but designers must avoid operation beyond the SOA boundary defined by V_CE, I_C, and time limits without external clamping.

Can ZTX560STOB be used in place of MPSA92 in existing designs?

ZTX560STOB is pin-compatible with MPSA92 in TO-92 packages and shares identical pinout (E-B-C), but its −500 V rating exceeds MPSA92's −300 V limit. Substitution is electrically safe only if the circuit's maximum V_CE does not exceed −300 V; otherwise, ZTX560STOB provides headroom but may require base drive adjustment due to higher h_FE.