Diodes Incorporated ZTX956STZ

Overview

ZTX956STZ 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 −2 A continuous collector current, −200 V V_CEO, −150 mV V_CE(sat) at −2 A/−400 mA drive, and 100–300 h_FE across 10 mA–2 A, enabling robust operation in DC-DC converter output stages and motor driver H-bridge high-side switches.

For engineers reviewing the ZTX956STZ datasheet, ZTX956STZ pinout, ZTX956STZ application, or ZTX956STZ equivalent, key selection criteria include verified −200 V blocking capability, low −150 mV saturation voltage under full load, thermal resistance of 50 °C/W (junction-to-case), Spice model availability, and TO-92-compatible E-Line package compatibility with legacy PCB footprints.

Technical Context

The ZTX956STZ is a PNP bipolar junction transistor optimized for medium-power switching where high breakdown voltage and low saturation loss are critical. Its −220 V V_CBO, −200 V V_CEO, and −6 V V_EBO support operation in high-voltage DC rails up to −200 V, while its f_T of 110 MHz enables fast turn-on/turn-off transitions in pulse-width modulated loads.

Thermal performance is defined by R_th(j-case) = 50 °C/W and R_th(j-amb) = 150 °C/W, with safe operating area validated for single-pulse and DC conditions up to +175 °C junction temperature. Saturation behavior is characterized across −55 °C to +175 °C, with V_CE(sat) remaining ≤ −250 mV at −2 A/−400 mA drive even at elevated temperatures.

Key Specifications

Pinout & Package

Package: E-Line TO-92 compatible (3-lead, plastic, through-hole), pin assignment confirmed per Diodes Incorporated datasheet issue 3 (June 1994) and mechanical drawing 3-324: Emitter (E), Base (B), Collector (C) - left-to-right when viewing flat side with leads down.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZTX956STZ, ZTX951 trades voltage headroom for cost and ZTX956STZ's −200 V rating remains unmatched in TO-92; MJD2955T4G offers higher current but sacrifices voltage capability and package compatibility-making ZTX956STZ uniquely balanced for medium-power, high-voltage, through-hole designs.

Availability

ZTX956STZ is available at Aetrix Electronics and suitable for industrial motor control, telecom DC-DC converters, relay interface modules, and analog power regulation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ZTX956STZ 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 components for industrial, automotive, and computing applications.

The ZTX956STZ belongs to Diodes' legacy high-voltage bipolar transistor product line, engineered specifically for ruggedized switching in harsh-environment power interfaces where TO-92 compatibility, thermal resilience, and voltage margin are design-critical.

FAQ

What is the maximum safe operating voltage for ZTX956STZ in DC applications?

The ZTX956STZ is rated for −200 V V_CEO and −220 V V_CBO at T_amb = 25 °C. For continuous DC operation, voltage must remain ≤−200 V with appropriate safety margin (typically ≥20%) to avoid degradation. Derating is required above +25 °C ambient per the published thermal curve.

Does ZTX956STZ require a heatsink in 1.2 W continuous operation?

At 1.2 W dissipation and T_amb = 25 °C, junction temperature rise is ΔT = 1.2 W × 150 °C/W = 180 °C - exceeding the +200 °C absolute max. A heatsink is mandatory. With case-to-heatsink thermal resistance ≤10 °C/W, R_th(j-amb) drops below 60 °C/W, keeping T_j < 150 °C at 1.2 W.

Can ZTX956STZ be used in linear amplifier configurations?

Yes - its h_FE stability (100–300) across 10 mA–2 A and low distortion characteristics support Class-A and AB linear amplification. However, V_CE(sat) and thermal limits constrain usable output swing; it is best suited for low-frequency (<1 MHz), medium-power audio or sensor signal buffering where voltage gain >20 is required.

Is the Spice model for ZTX956STZ publicly accessible?

Yes - Diodes Incorporated provides an industry-standard SPICE model (PSPICE-compatible) for ZTX956STZ on its official product page and through authorized distributor portals. The model includes temperature-dependent parameters, junction capacitance, and accurate saturation behavior validated against measured DC and transient data.