Diodes Incorporated ZTX795ASTOA

Overview

ZTX795ASTOA from Zetex Semiconductors (now Diodes Incorporated) is a PNP silicon planar medium-power high-gain bipolar junction transistor rated for −140 V V_CEO, 500 mA continuous collector current, and 1.5 W PCB-mounted power dissipation. It delivers h_FE = 250 at I_C = −0.2 A, V_CE = −2 V, with V_CE(sat) = −0.25 V at I_C = −500 mA / I_B = −50 mA, and is commonly used in linear voltage regulation and high-voltage switching stages.

For engineers reviewing the ZTX795ASTOA datasheet, ZTX795ASTOA pinout, ZTX795ASTOA application, or ZTX795ASTOA equivalent, key selection criteria include verified −140 V breakdown rating, low saturation voltage under high-current drive, thermal resistance of 175 °C/W (junction-to-ambient, PCB-mounted), gain consistency across −10 mA to −300 mA, and TO-92-compatible E-Line package compatibility.

Technical Context

This PNP BJT operates in active, saturation, and cutoff regions with guaranteed V_(BR)CEO = −140 V and V_(BR)CBO = −140 V, enabling use in high-side switching and negative-rail amplification. Its f_T = 100 MHz at I_C = −50 mA supports moderate-speed switching applications up to several tens of MHz.

The device exhibits low V_CE(sat) (−0.25 V typical at −500 mA) and V_BE(sat) (−0.95 V at −500 mA), minimizing conduction loss in power control circuits. Thermal design is supported by R_th(j–amb) = 175 °C/W (PCB mount, 1 in² copper) and R_th(j–case) = 70 °C/W, allowing stable operation from −55 °C to +200 °C junction temperature.

Key Specifications

Pinout & Package

Package: TO-92-compatible E-Line (3-lead, plastic, through-hole). Pin identification follows standard emitter-base-collector (E-B-C) layout as marked on device body and confirmed in Zetex documentation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD2955T4G and BC807-40, ZTX795ASTOA uniquely balances −140 V rating, TO-92 mountability, and 1.5 W PCB power handling-making it optimal for legacy through-hole systems requiring high-voltage robustness without heatsinks.

Availability

ZTX795ASTOA is available at Aetrix Electronics and suitable for linear voltage regulation, high-voltage switching, analog amplifier stages, and power supply protection requiring stable component supply and long-term obsolescence resilience.

Supply support for ZTX795ASTOA 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, acquired by Diodes Incorporated in 2008, specialized in high-performance discrete semiconductors for analog and power applications.

ZTX795ASTOA belongs to the ZTX series of high-voltage PNP transistors designed specifically for industrial power control, telecom infrastructure, and ruggedized analog signal conditioning where reliability at extreme V_CEO and thermal stability are critical.

FAQ

What is the maximum safe operating voltage for ZTX795ASTOA in continuous DC applications?

The absolute maximum V_CEO is −140 V, and V_CBO is also −140 V. For reliable long-term operation, design should limit steady-state collector-emitter voltage to ≤−110 V to maintain sufficient margin against transients and temperature-induced drift, per Zetex application guidance for medium-power BJTs.

Can ZTX795ASTOA be used in switching power supplies above 100 kHz?

Yes - its f_T = 100 MHz and t_on/t_off = 100/1900 ns support operation up to ~500 kHz in hard-switched topologies. However, switching losses increase significantly above 200 kHz due to stored charge and minority-carrier lifetime; soft-switching or synchronous rectification is recommended for higher-frequency designs.

Is ZTX795ASTOA RoHS-compliant and halogen-free?

Yes - as a Diodes Incorporated product (post-acquisition), ZTX795ASTOA meets RoHS Directive 2011/65/EU and is certified halogen-free per IEC 61249-2-21. The TO-92 E-Line package uses lead-free matte tin plating and compliant molding compound, with full material declarations available via Diodes' compliance portal.

How does thermal performance change when mounted on 0.5 in² copper instead of the specified 1 in²?

Derating is nonlinear: reducing copper area from 1 in² to 0.5 in² increases R_th(j–amb) from 175 °C/W to approximately 240 °C/W. At 25 °C ambient, max continuous power drops from 1.5 W to ~1.1 W - requiring either reduced I_C, forced airflow, or derated ambient temperature to avoid exceeding 200 °C T_j.