onsemi KSA940H2

Overview

KSA940H2 from onsemi is a PNP epitaxial silicon transistor designed as a vertical deflection output power amplifier in CRT display systems, with −150 V V_CEO, −1.5 A I_C, 25 W P_C (T_C=25°C), h_FE = 40–140 at −500 mA, and TO-220-3LD package. It serves as the complement to KSC2073 in push-pull horizontal/vertical deflection stages.

For engineers reviewing the KSA940H2 datasheet, pinout, applications, or equivalent options, key selection criteria include safe operating area (SOA) compliance at high-voltage switching, DC current gain stability under pulse load, V_CE(sat) ≤ −1.5 V at −500 mA/−50 mA drive, and thermal derating above 25°C case temperature.

Technical Context

This device operates in linear amplification and switching modes within CRT deflection yoke driver circuits, requiring robust secondary breakdown immunity and controlled f_T (4 MHz typical) for stable 15.734 kHz horizontal and 60 Hz vertical sweep frequencies. Its −5 V V_EBO rating supports base bias networks with standard resistor-divider configurations.

The KSA940H2 shares identical absolute maximum ratings and electrical characteristics with the base KSA940, including Cob = 55 pF at −10 V V_CB, V_BE(on) = −0.65 to −0.85 V at −500 mA, and junction temperature limit of 150°C - confirming its use in thermally constrained chassis-mounted applications.

Key Specifications

Pinout & Package

Package: TO-220-3LD (Case 340AT), lead-free, through-hole mount with integral metal tab for heatsinking. Pin 1 = Base, Pin 2 = Collector (tab-connected), Pin 3 = Emitter.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP vertical deflection amplifier applications.

Compared with MJD127G and KSA940TU, the KSA940H2 provides full −150 V ruggedness and 25 W thermal capacity in a through-hole TO-220 format, making it uniquely suitable for legacy CRT service and high-reliability analog video designs where voltage margin and heatsink compatibility are critical.

Availability

KSA940H2 is available at Aetrix Electronics and suitable for CRT television repair, analog oscilloscope maintenance, and industrial monitor refurbishment requiring stable component supply and long-term obsolescence support.

Supply support for KSA940H2 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 specializing in energy-efficient power management, analog, sensors, and logic devices for automotive, industrial, and consumer markets.

The KSA940H2 belongs to onsemi's legacy bipolar power transistor product line, engineered specifically for high-voltage, medium-power analog video deflection and linear regulation applications in CRT-based systems.

FAQ

Is KSA940H2 a direct replacement for the original KSA940 in CRT TV repair?

Yes, the KSA940H2 is functionally identical to the base KSA940, sharing all absolute maximum ratings, electrical characteristics, TO-220-3LD package, and pinout. The "H2" suffix denotes a tape-and-reel packaging variant compliant with modern SMT handling - no circuit or layout changes are needed when replacing legacy KSA940 units in CRT vertical output stages.

What is the safe operating area (SOA) limit for KSA940H2 at 100°C case temperature?

Per the KSA940 datasheet Figure 4 (Safe Operating Area), the KSA940H2 maintains a DC SOA boundary of approximately 60 V × 0.4 A at T_C = 100°C. Derating follows the linear curve shown in Figure 5, where P_C reduces from 25 W at 25°C to ~12.5 W at 100°C - ensuring reliable operation under sustained thermal stress in enclosed TV chassis.

Can KSA940H2 be used in parallel with another KSA940H2 for higher current capability?

No - the KSA940H2 lacks built-in emitter ballasting resistors and exhibits positive thermal feedback, making current sharing unstable without external emitter resistors (≥0.22 Ω each). Parallel operation is not recommended unless individual current-limiting resistors and matched h_FE bins are implemented, as unbalanced conduction may cause thermal runaway in the KSA940H2 pair.

Does KSA940H2 require a heatsink in typical CRT vertical output applications?

Yes, the KSA940H2 must be mounted to a heatsink rated ≥2.5°C/W to maintain T_J ≤ 150°C under worst-case 25 W dissipation. In practice, a 10–15 cm² aluminum finned heatsink with thermal grease is standard for CRT vertical output stages using the KSA940H2, especially given its TO-220-3LD metal tab connection to collector.

What is the maximum frequency response supported by KSA940H2 in small-signal amplification?

The KSA940H2 has a current-gain bandwidth product (f_T) of 4 MHz typical at −500 mA and −10 V V_CE. In small-signal common-emitter configuration, usable bandwidth is limited to <1 MHz due to decreasing h_FE and rising output capacitance; it is optimized for 15.734 kHz horizontal and 60 Hz vertical deflection, not RF or audio amplification.