Diodes Incorporated ZTX757STZ

Overview

ZTX757STZ from Diodes Incorporated is a PNP silicon planar medium-power high-voltage bipolar junction transistor (BJT) designed for switching and linear amplification in high-voltage DC-DC converters, relay drivers, and industrial control interfaces. It delivers −300 V V_CEO, −0.5 A continuous collector current, 1 W power dissipation at 25°C, and h_FE ≥ 40 at −100 mA/−5 V, operating reliably from −55°C to +200°C.

For engineers reviewing the ZTX757STZ datasheet, ZTX757STZ pinout, ZTX757STZ application, or ZTX757STZ equivalent, key selection criteria include verified high-voltage blocking capability (−300 V V_CEO), low saturation voltage (−0.5 V at −100 mA/−10 mA), stable gain across temperature, TO-92 mechanical compatibility, and safe operating area compliance for pulsed industrial loads.

Technical Context

This PNP BJT operates with emitter-grounded configuration in common-emitter topology, supporting active-region amplification and saturated-switching modes. Its −300 V V_CEO rating enables use in off-line auxiliary supplies and HV bias rails where breakdown margin exceeds −250 V system requirements.

Thermal design relies on its 200°C maximum junction temperature and 1 W P_tot at T_amb = 25°C, with derating to zero at 150°C ambient. Transition frequency f_T = 30 MHz and output capacitance C_obo = 20 pF support moderate-speed switching (<500 kHz) in flyback snubber circuits and solenoid drivers.

Key Specifications

Pinout & Package

Supplied in E-Line TO-92 compatible package (JEDEC TO-92 variant), molded plastic case with axial leads. Standard lead assignment: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector (viewed from flat side, leads down).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZTX757STZ, ZTX756STZ trades 100 V blocking for identical cost and fit; MJD2955G offers tenfold current capacity but fails at one-quarter the voltage-neither is pin-compatible, and both require layout and thermal redesign.

Availability

ZTX757STZ is available at Aetrix Electronics and suitable for industrial relay drivers, off-line auxiliary power supplies, high-voltage bias generators, and HVAC solenoid control requiring stable component supply across extended temperature and voltage ranges.

Supply support for ZTX757STZ 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, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and the Philippines.

ZTX757STZ belongs to the ZTX series of high-voltage bipolar transistors developed for industrial power interface and control applications where reliability under sustained voltage stress is critical.

FAQ

Is ZTX757STZ RoHS compliant and halogen-free?

Yes, ZTX757STZ meets RoHS Directive 2011/65/EU and is certified halogen-free per IEC 61249-2-21. The TO-92 package uses matte tin-plated leads and environmentally compliant molding compound, with full material declarations available upon request.

What is the maximum safe continuous collector current at 100°C ambient?

At T_amb = 100°C, the device's power derating curve reduces P_tot to approximately 0.5 W. With V_CE(sat) ≈ −0.5 V, the corresponding safe continuous I_C is ~1 A-but absolute maximum I_C remains −0.5 A per datasheet limit, so actual use must not exceed −0.5 A regardless of temperature.

Can ZTX757STZ be used in avalanche mode?

No-ZTX757STZ is not characterized or rated for repetitive avalanche operation. Its safe operating area (SOA) chart specifies only forward-biased second breakdown limits; operation beyond V_CEO risks irreversible junction failure without guaranteed energy absorption capability.

Does the "STZ" suffix indicate tape-and-reel packaging?

Yes, the "STZ" suffix denotes standard tape-and-reel packaging per EIA-481-D: 2,000 units per reel, 12 mm tape width, 8 mm pocket pitch. This format supports automated pick-and-place assembly and is distinct from bulk (ZTX757) or ammo-pack (ZTX757AZ) variants.