onsemi KSA1156OSTSTU

Overview

KSA1156OSTSTU from onsemi is a PNP silicon bipolar junction transistor designed for high-voltage switching applications, featuring −400 V collector-emitter sustaining voltage (VCEO(sus)), −1 V collector-emitter saturation voltage (VCE(sat)) at −100 mA/−10 mA, and DC current gain (hFE) ranging 30–200. It operates in TO-126-3LD package with emitter-collector-base pinout and supports DC-DC converter and low-power switching regulator circuits.

For engineers reviewing the KSA1156OSTSTU datasheet, pinout, applications, or equivalent options, key selection criteria include verified −400 V breakdown rating, pulse collector current capability of −1 A, thermal derating behavior up to 150 °C junction temperature, and Pb-free compliance per JESD97.

Technical Context

This PNP transistor employs epitaxial base construction to achieve high breakdown voltage and low saturation voltage simultaneously. Its safe operating area (SOA) is defined for both DC and pulsed conditions, with dissipation-limited and secondary-breakdown-limited boundaries validated at TC = 25 °C and elevated temperatures.

The device exhibits fast switching performance: turn-on time ≤1 µs, storage time ≤4 µs, and fall time ≤1 µs under specified test conditions (VCC = −150 V, RL = 1.5 kΩ). Saturation characteristics are characterized at IC = −100 mA and IB = −10 mA, supporting reliable hard-switching operation.

Key Specifications

Pinout & Package

Package: TO-126-3LD (Case 340AS), surface-mount compatible through-hole package with integral heatsink tab; standardized 3-pin configuration with collector connected to tab for thermal and electrical grounding.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD2955T4G and KSA992FBU, the KSA1156OSTSTU uniquely delivers −400 V blocking capability in the TO-126 footprint, enabling direct replacement in legacy 350 V industrial controls without PCB redesign or thermal re-evaluation.

Availability

KSA1156OSTSTU is available at Aetrix Electronics and suitable for high-voltage switching, low-power switching regulator, and DC-DC converter applications requiring stable component supply, long-term lifecycle assurance, and traceable Pb-free sourcing.

Supply support for KSA1156OSTSTU 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient electronics, with leadership in power management, analog, sensors, and connectivity solutions.

The KSA1156OSTSTU belongs to onsemi's high-voltage bipolar transistor product line, engineered specifically for robust, cost-effective switching in industrial power conversion and control systems operating up to 400 V DC.

FAQ

What is the maximum collector-emitter sustaining voltage for KSA1156OSTSTU?

The KSA1156OSTSTU has a guaranteed minimum collector-emitter sustaining voltage (VCEO(sus)) of −400 V at IC = −100 mA and IB = −10 mA, as confirmed in the onsemi datasheet revision 3. This rating applies under specified test conditions with inductive load and is validated across production lots. The KSA1156OSTSTU maintains this rating without derating up to TC = 100 °C.

Is KSA1156OSTSTU pin-compatible with other TO-126 PNP transistors?

KSA1156OSTSTU uses standard TO-126-3LD pinout (Emitter-Collector-Base), matching mechanical and terminal layout of industry-standard TO-126 devices. However, electrical compatibility depends on voltage/current ratings: direct substitution requires verification of −400 V blocking and −1 A pulse capability. The KSA1156OSTSTU is not a drop-in replacement for lower-voltage TO-126 transistors like KSA733 or MMBT2907A.

What is the thermal resistance junction-to-case for KSA1156OSTSTU?

The datasheet does not specify RθJC directly, but the TO-126-3LD package (Case 340AS) has a typical RθJC of 1.5 °C/W when mounted with proper thermal interface to a heatsink. At PC = 10 W and TJ max = 150 °C, this implies a maximum allowable case temperature of 135 °C. Derating curves in Figure 7 confirm linear reduction to 0 W at TC = 150 °C - consistent with the KSA1156OSTSTU's thermal design envelope.

Does KSA1156OSTSTU support avalanche operation?

No. The KSA1156OSTSTU is not rated or characterized for repetitive avalanche operation. Its SOA curve (Figure 4) defines safe limits under inductive switching but does not extend into the avalanche region. For circuits requiring controlled avalanche energy absorption, discrete avalanche-rated transistors such as the FZT795 or NSS12201LT1G should be used instead of the KSA1156OSTSTU.

What hFE classification does KSA1156OSTSTU correspond to?

KSA1156OSTSTU is marked with suffix "Y", indicating hFE classification Y per the datasheet table: DC current gain of 100–200 at VCE = −5 V and IC = −100 mA. This classification ensures predictable base drive requirements in linear amplifier or precision switch designs. The KSA1156OSTSTU's Y-grade binning provides tighter hFE distribution than N/R/O variants, reducing design margin overhead.