Diodes Incorporated ZTX958STZ

Overview

ZTX958STZ from Diodes Incorporated is a PNP silicon planar medium-power high-current transistor designed for switching and linear amplification in industrial power control circuits. It delivers −0.5 A continuous collector current, −1.5 A peak pulse current, and exhibits very low V_CE(sat) (−100 mV at I_C = −10 mA, I_B = −1 mA), with h_FE ≥ 100 at I_C = −10 mA and f_T = 85 MHz - enabling robust performance in DC-DC converter output stages.

For engineers reviewing the ZTX958STZ datasheet, ZTX958STZ pinout, ZTX958STZ application, or ZTX958STZ equivalent, key selection criteria include its −400 V V_CEO rating, TO-92-compatible E-Line package, thermal resistance of 150 °C/W (junction-to-ambient), −150 mV V_CE(sat) at −100 mA, and verified operation up to +200 °C junction temperature.

Technical Context

This PNP bipolar junction transistor operates in common-emitter configuration with base-driven saturation switching and linear gain control. Its design emphasizes high-voltage blocking (−400 V V_CEO), low on-state loss (V_CE(sat) ≤ −300 mV at −500 mA), and stable h_FE across −55 °C to +175 °C ambient.

The device supports pulsed operation up to 1.5 A with 300 µs pulse width and ≤2% duty cycle, and features a 19 pF C_obo at V_CB = −20 V, enabling use in moderate-frequency switching applications up to ~10 MHz practical bandwidth.

Key Specifications

Pinout & Package

Package: TO-92-compatible E-Line (3-lead, straight lead form, epoxy molded). Pin identification follows standard B-C-E sequence when viewed with flat side facing user and leads downward: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZTX958STZ, ZTX951STZ trades 200 V blocking capability and thermal margin for lower unit cost, while BC807-40 sacrifices voltage rating, package ruggedness, and modeling support to meet miniaturization goals - neither offers drop-in compatibility in high-reliability industrial systems.

Availability

ZTX958STZ is available at Aetrix Electronics and suitable for industrial relay drivers, DC-DC converter output stages, motor commutation circuits, and high-temperature sensor signal conditioning requiring stable component supply and long-term manufacturability.

Supply support for ZTX958STZ 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, specializing in high-reliability power management, signal integrity, and protection solutions for industrial and automotive markets.

The ZTX series targets medium-power bipolar switching applications demanding extended temperature operation, high-voltage robustness, and proven field reliability - particularly in factory automation, energy infrastructure, and harsh-environment controls.

FAQ

What is the maximum safe operating voltage for ZTX958STZ in DC switching applications?

The absolute maximum collector-emitter voltage (V_CEO) is −400 V, but derating is required for reliability. For continuous DC operation, Diodes Incorporated recommends limiting V_CE to ≤ −320 V at T_j ≤ +150 °C. At elevated temperatures or with inductive loads, transient spikes must remain within the SOA curve shown in Figure 3-332 of the datasheet.

Can ZTX958STZ be used in linear amplifier configurations?

Yes - its h_FE remains stable from −10 mA to −1 A, and V_CE(sat) is well-characterized across current ranges. However, linear use requires strict thermal management: at 1.2 W dissipation, junction temperature rises 180 °C above ambient, so heatsinking or forced air is mandatory above 100 mW continuous output.

Is ZTX958STZ RoHS compliant and halogen-free?

Yes - ZTX958STZ meets RoHS Directive 2011/65/EU and is certified halogen-free per IEC 61249-2-21. The device uses lead-free matte tin plating on leads and conforms to JEDEC J-STD-020 moisture sensitivity level MSL3, with a floor life of 168 hours at 30 °C/60% RH.

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

The official Diodes Incorporated SPICE model for ZTX958STZ includes temperature-dependent β, V_BE, and saturation resistances, and supports transient thermal simulation via built-in thermal network elements. It is validated against measured f_T, C_obo, and switching waveforms at −55 °C, +25 °C, and +125 °C per the datasheet test conditions.