onsemi KSD1691OSTU

Overview

KSD1691OSTU from onsemi is an NPN epitaxial silicon power transistor in TO-126-3LD package, rated for 60 V V_CEO, 5 A continuous collector current, and 1.3 W power dissipation at T_A = 25 °C; used in high-current linear and switching applications such as DC motor drivers and power supply output stages.

For engineers reviewing the KSD1691OSTU datasheet, pinout, applications, or equivalent options, key selection criteria include verified V_CE(sat) ≤ 0.3 V at I_C = 2 A/I_B = 0.2 A, h_FE range of 100–400 at I_C = 2 A, and complementary pairing with KSB1151 for push-pull designs.

Technical Context

This device operates as a medium-power NPN bipolar junction transistor optimized for low-saturation switching and linear amplification. Its design emphasizes high DC current gain (h_FE2 = 100–400 at V_CE = 1 V, I_C = 2 A) and low V_CE(sat) (typ. 0.1 V), enabling efficient operation in saturated-switching topologies.

The TO-126-3LD package provides direct case thermal conduction path with 20 W power dissipation capability at T_C = 25 °C, supporting stable operation under sustained load conditions when mounted to heatsinks. Absolute maximum ratings include 60 V collector-base and collector-emitter voltages, and 150 °C junction temperature limit.

Key Specifications

Pinout & Package

Package: TO-126-3LD (Case 340AS), thermally enhanced through-hole package with collector-connected tab for direct heatsink mounting.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN power transistor applications.

Compared with MJD127G and KSD1691GSTU, the KSD1691OSTU offers through-hole manufacturability and mid-range h_FE binning ideal for cost-sensitive, thermally managed switching applications where exact gain matching is secondary to robust saturation performance.

Availability

KSD1691OSTU is available at Aetrix Electronics and suitable for DC motor control, linear regulator pass elements, switched-mode power supply output stages, and high-current relay drivers requiring stable component supply across industrial OEM programs.

Supply support for KSD1691OSTU 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, delivering power, analog, sensor, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The KSD1691OSTU belongs to onsemi's legacy discrete power transistor family, engineered for high-current linear and switching applications where low saturation voltage, thermal robustness, and complementary PNP pairing are essential design requirements.

FAQ

What is the maximum continuous collector current rating for KSD1691OSTU?

The KSD1691OSTU has a maximum continuous collector current (I_C) rating of 5 A at T_A = 25 °C. This rating assumes adequate PCB copper area or heatsinking to maintain junction temperature within 150 °C. At elevated ambient temperatures, derating applies per the published power dissipation curve in the datasheet. The KSD1691OSTU must not exceed this limit in DC or high-duty-cycle applications to ensure reliability.

Is KSD1691OSTU pin-compatible with KSD1691GSTU?

Yes, the KSD1691OSTU and KSD1691GSTU share identical TO-126-3LD packaging, pinout (Emitter-Collector-Base), and mechanical footprint. They differ only in h_FE grading: KSD1691OSTU is h_FE Class O (100–200), while KSD1691GSTU is Class G (200–400). No PCB changes are required when substituting between these variants, though system-level gain stability should be verified.

What is the typical V_CE(sat) of KSD1691OSTU under standard test conditions?

The typical V_CE(sat) of KSD1691OSTU is 0.1 V, measured at I_C = 2 A and I_B = 0.2 A with V_CE = 1 V. The maximum specified value is 0.3 V under those same conditions. This low saturation voltage directly reduces conduction losses in switching applications, making the KSD1691OSTU suitable for high-efficiency power stages where thermal management is critical.

Does KSD1691OSTU have a complementary PNP transistor?

Yes, the KSD1691OSTU is explicitly designed as the NPN complement to the KSB1151 PNP transistor. Both devices share matching voltage ratings (60 V), current capabilities (5 A), and TO-126-3LD packaging, enabling balanced push-pull amplifier stages, H-bridge motor drivers, and complementary output configurations. Their matched characteristics simplify thermal and electrical design in dual-transistor topologies.

What is the junction-to-case thermal resistance (R_θJC) of KSD1691OSTU?

The junction-to-case thermal resistance (R_θJC) for KSD1691OSTU is not explicitly published in the provided datasheet. However, its TO-126-3LD package (Case 340AS) supports 20 W collector dissipation at T_C = 25 °C, implying R_θJC ≈ 1.25 °C/W. For precise thermal modeling, users should refer to onsemi's official thermal characterization data or perform empirical measurement under representative mounting conditions. The KSD1691OSTU requires direct metal tab contact with heatsink for optimal thermal performance.