onsemi KSC2335R

Overview

KSC2335R from Fairchild Semiconductor is an NPN epitaxial silicon transistor designed for high-voltage, high-speed switching in industrial power converters and motor control circuits. It features a 400 V V_CEO, 7 A DC collector current, 40 W collector dissipation at T_C=25°C, 1.2 V V_BE(sat) at I_C=3 A/I_B=0.6 A, and 1 µs turn-on time - enabling robust performance in flyback and snubberless inductive load switching.

For engineers reviewing the KSC2335R datasheet, pinout, applications, or equivalent options, key selection criteria include its 450 V V_CEX(sus)1 clamped sustaining voltage, TO-220 package thermal capability, h_FE classification R (20–40 at I_C=1 A), and safe operating area validated up to 100°C case temperature under pulsed conditions.

Technical Context

The KSC2335R employs epitaxial base construction to achieve fast switching with low storage time (t_STG = 2.5 µs) and controlled saturation characteristics. Its rugged reverse-bias SOA supports inductive turn-off with 180 µH clamp and −5 V V_BE(off), while forward-bias SOA is rated for 3 A continuous operation at 150 V with 50 Ω load.

Designed for hard-switched industrial applications, it delivers stable h_FE across I_C = 0.1–3 A (20–40 min), low V_CE(sat) = 1 V, and tight parameter grouping per R-class binning - ensuring predictable gate drive requirements and thermal margin in 50–100 kHz SMPS stages.

Key Specifications

Pinout & Package

Package: TO-220 (3-lead, straight lead, insulated tab). Dimensions conform to JEDEC TO-220AC standard: 15.90 mm × 10.08 mm × 18.95 mm max, with 2.54 mm lead pitch and 3.60 mm mounting hole diameter.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD2955G and BU508A, the KSC2335R provides optimal balance of 400 V rating, TO-220 thermal performance, fast switching, and binned h_FE - making it preferred for cost-sensitive, medium-power industrial switchers where layout space and drive simplicity matter.

Availability

KSC2335R is available at Aetrix Electronics and suitable for industrial motor drives, switch-mode power supplies, inductive load switching, and welding control circuits requiring stable component supply and long-lifecycle support.

Supply support for KSC2335R 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The KSC2335R belongs to Fairchild's high-voltage bipolar transistor product line, engineered specifically for ruggedized industrial switching applications demanding reliable 400 V+ operation and fast transient response.

FAQ

What is the maximum safe operating voltage for KSC2335R in continuous DC mode?

The KSC2335R has a V_CEO rating of 400 V, meaning it can safely block up to 400 V between collector and emitter with the base open. This is the maximum continuous DC voltage applicable in normal operation. Exceeding this value risks avalanche breakdown and permanent device failure. Always maintain design margins - typically ≤80% of V_CEO - especially under temperature or transient stress. The KSC2335R datasheet confirms this rating at T_C=25°C.

Does KSC2335R require a heatsink in typical industrial applications?

Yes, the KSC2335R requires a heatsink when dissipating more than ~5 W continuously, as its 40 W P_C rating applies only at T_C=25°C. In real-world enclosures with ambient temperatures above 40°C and natural convection, thermal resistance rises significantly. For example, at 3 A DC load with 1 V V_CE(sat), power dissipation reaches 3 W - often manageable with minimal heatsinking. But at higher currents or pulsed loads, a properly sized TO-220-compatible heatsink is essential. The KSC2335R thermal data shows derating begins above 25°C case temperature.

How does the R-class hFE binning affect base drive design for KSC2335R?

The R-class designation for KSC2335R specifies an h_FE range of 20–40 at I_C=1 A and V_CE=5 V. This binning ensures predictable base current requirements: for 3 A collector current, designers can target 0.6–1.5 A base drive to guarantee saturation across all units. Without binning, h_FE variation could force overdesign of driver stages. The KSC2335R's tight R-class spec directly simplifies gate/base driver selection and improves production yield consistency.

Can KSC2335R replace BU208A in existing 400 V flyback designs?

The KSC2335R is not a direct replacement for BU208A due to differences in SOA, switching speed, and h_FE behavior. While both are 400 V NPN transistors, BU208A has slower t_ON (~2 µs) and no clamped SOA validation. The KSC2335R's 1 µs t_ON and 450 V V_CEX(sus)1 may improve efficiency but require revalidation of base drive timing and snubber networks. Use KSC2335R only after verifying layout parasitics and thermal limits in the target circuit.

Is KSC2335R suitable for automotive under-hood applications?

No, the KSC2335R is not qualified for automotive under-hood use. Its datasheet specifies industrial use only, with storage temperature ranging from −55°C to +150°C but no AEC-Q101 qualification, PPAP documentation, or guaranteed operation above 125°C junction temperature. Automotive applications demand extended temperature validation, enhanced ESD robustness, and failure-in-time (FIT) data - none of which are provided for the KSC2335R. For such environments, consider AEC-Q101-certified alternatives instead of the KSC2335R.