onsemi KSC2500CTA

Overview

KSC2500CTA from Fairchild Semiconductor is an NPN epitaxial silicon transistor designed for medium-power amplification and low-saturation switching in discrete amplifier stages and power control circuits, with V_CEO = 10 V, I_C = 2 A DC, V_CE(sat) ≤ 0.5 V at I_C = 2 A / I_B = 50 mA, h_FE ≥ 140 at I_C = 0.5 A, and f_T = 150 MHz - used in audio preamp output stages and relay driver interfaces.

For engineers reviewing the KSC2500CTA datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed h_FE classification (Class A: 140–240), TO-92L package thermal limits (P_C = 900 mW), safe operating area under pulsed conditions (I_CP = 5 A, PW ≤ 10 ms), and V_BE(on) behavior across I_C = 0.01–5 A.

Technical Context

This NPN bipolar junction transistor operates with emitter-common configuration and supports linear amplification up to 150 MHz via its current-gain bandwidth product. Its low V_CE(sat) and high h_FE enable efficient Class-A/AB audio output buffering and DC-coupled switching where base drive efficiency matters.

The device features a maximum junction temperature of 150°C and storage range from –55°C to +150°C, with breakdown ratings including BVCBO = 30 V, BVEBO = 6 V, and BVCES = 30 V - confirming suitability for low-voltage, moderate-current interface applications without secondary protection circuitry.

Key Specifications

Pinout & Package

Package: TO-92L - molded plastic case with 3.90 mm lead spacing, 13.50 mm body length, and 1.45 mm max height; optimized for manual insertion and board-level thermal relief.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC337-40 and MPSA14, the KSC2500CTA uniquely delivers 2 A DC current handling with Class A h_FE consistency and 900 mW power dissipation in TO-92L - making it the only option among the three qualified for sustained 1–2 A load switching without forced cooling.

Availability

KSC2500CTA is available at Aetrix Electronics and suitable for audio amplifier output stages, electromechanical relay drivers, constant-current LED regulators, and logic-level translation circuits requiring stable component supply across production lifecycles.

Supply support for KSC2500CTA 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 analog, discrete, and power management ICs before its acquisition by ON Semiconductor in 2016; known for robust, industry-standard bipolar and MOSFET devices.

The KSC2500CTA belongs to Fairchild's legacy medium-power NPN transistor family engineered for cost-sensitive, high-reliability linear and switching applications in consumer audio, industrial controls, and automotive subsystems.

FAQ

What is the maximum continuous collector current rating for KSC2500CTA?

The KSC2500CTA has a maximum continuous collector current (I_C) rating of 2 A at T_A = 25°C. Derating is required above 25°C ambient - approximately 16 mA/°C reduction beyond 25°C per the datasheet's thermal resistance curve. This rating applies strictly under free-air conditions with no heatsink; actual usable current depends on PCB copper area and airflow.

Does KSC2500CTA have a specified h_FE classification, and what does "Class A" mean for this part?

Yes, KSC2500CTA is classified as Class A for h_FE1, meaning its DC current gain falls within 140–240 at V_CE = 1 V and I_C = 0.5 A. This binning ensures tighter gain distribution across units, simplifying bias network design in production amplifiers and eliminating need for post-manufacture h_FE sorting.

What is the safe operating area (SOA) limitation for KSC2500CTA during pulsed operation?

The KSC2500CTA supports pulsed collector current up to 5 A with pulse width ≤ 10 ms and duty cycle ≤ 30%. This SOA limit is defined in the datasheet's Figure 5 and assumes T_J ≤ 150°C. Exceeding these conditions risks second breakdown or permanent degradation even if average power appears within P_C = 900 mW.

Can KSC2500CTA be used in common-base configuration, and what is its Cob value?

Yes, KSC2500CTA can operate in common-base mode, with Cob = 27 pF measured at V_CB = 10 V, f = 1 MHz, and IE = 0. This output capacitance directly impacts high-frequency gain roll-off and stability margins - especially critical in RF amplifier or oscillator designs where neutralization may be required above 30 MHz.

Is KSC2500CTA RoHS compliant, and what is its lead finish?

KSC2500CTA was manufactured prior to RoHS enforcement (Rev. A2, September 2002) and carries a lead (Pb)-containing finish. It is not RoHS-compliant per EU Directive 2011/65/EU. For new designs requiring compliance, consider modern alternatives like ON Semiconductor's NSS20501MR6T1G or Diodes Inc.'s DXT75100Q-13, which offer comparable specs with Pb-free terminations.