Diodes Incorporated ZTX757STOB

Overview

ZTX757STOB from Diodes Incorporated is a PNP silicon planar medium-power high-voltage transistor with V_CEO = −300 V, I_C = −0.5 A continuous, P_tot = 1 W at T_amb = 25°C, h_FE ≥ 40 at I_C = −100 mA, and f_T = 30 MHz - used in high-voltage DC-DC converter switching stages and industrial relay drivers.

For engineers reviewing the ZTX757STOB datasheet, ZTX757STOB pinout, ZTX757STOB application, or ZTX757STOB equivalent, key selection criteria include verified −300 V V_CEO rating, guaranteed h_FE ≥ 40 under −100 mA load, TO-92-compatible E-Line package thermal limits, and validated safe operating area up to 10 ms pulse width at 300 V.

Technical Context

This PNP bipolar junction transistor operates in linear or saturated switching mode with fixed base-driven control logic. Its −300 V V_CEO and −200 V V_CBO ratings enable use in flyback snubber circuits and high-side switch configurations where collector swings above ground potential.

Electrical behavior is characterized by V_CE(sat) = −0.5 V at I_C = −100 mA / I_B = −10 mA, V_BE(sat) = −1.0 V under same conditions, and C_obo = 20 pF at V_CB = −20 V - supporting stable high-voltage switching with predictable turn-off timing.

Key Specifications

Pinout & Package

E-Line TO-92-compatible plastic package with standard lead assignment: Emitter (pin 1), Base (pin 2), Collector (pin 3) - leads tinned for solderability, rated for 260°C reflow peak temperature.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZTX756STOB, ZTX757STOB provides critical extra 100 V blocking headroom for 240 V AC-derived rails; versus MJD2955G, it trades current/power capability for compact TO-92 integration and HV robustness - making it optimal for space-constrained, high-voltage discrete switching.

Availability

ZTX757STOB is available at Aetrix Electronics and suitable for industrial relay drivers, high-voltage DC-DC snubbers, telecom −48 V backup switches, and discrete HV linear regulator pass elements requiring stable component supply across extended production cycles.

Supply support for ZTX757STOB 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.

ZTX757STOB belongs to the ZTX series of high-voltage bipolar transistors designed specifically for industrial power control, telecom infrastructure, and ruggedized analog signal conditioning where reliability under voltage stress is paramount.

FAQ

What is the maximum allowable base-emitter reverse voltage for ZTX757STOB?

The absolute maximum V_EB is −5 V, specified as V_(BR)EBO with I_E = −100 µA and I_C = 0. Exceeding this risks permanent degradation of the emitter-base junction. Designers must ensure base drive circuitry clamps reverse voltage - e.g., using a 4.7 V Zener diode from base to emitter - especially in inductive switching applications.

Can ZTX757STOB be used in avalanche mode?

No - ZTX757STOB is not rated or characterized for controlled avalanche operation. Its V_(BR)CEO test condition specifies I_C = −10 mA with base open, and the SOA curve does not extend into second-breakdown region. Intentional avalanche use may cause parametric shift or catastrophic failure; external clamping is required for overvoltage protection.

Is ZTX757STOB RoHS compliant and halogen-free?

Yes - ZTX757STOB meets RoHS Directive 2011/65/EU and is certified halogen-free per IEC 61249-2-21. The E-Line TO-92 package uses matte tin-plated leads and halogen-free molding compound, with full compliance documentation available from Diodes Incorporated's product change notices and material declarations.

How does thermal resistance θ_JA vary between PCB mounting configurations?

θ_JA is 200°C/W on FR-4 with minimal copper (JEDEC standard 1S0P). With 1 in² 2-oz copper pad connected to collector pin, θ_JA improves to ≈85°C/W. No θ_JC is published - junction-to-case thermal path relies on lead conduction, so board-level copper area and via count directly determine real-world thermal performance in continuous operation.