onsemi KSA931YTA

Overview

KSA931YTA from ON Semiconductor is a PNP epitaxial silicon transistor designed for low-frequency amplification and medium-speed switching applications, with VCBO = −80 V, VCEO = −60 V, IC = −700 mA, PC = 1 W, and hFE = 120–240 (Class Y). It serves as a complement to the NPN KSC2331 in push-pull amplifier stages and power control circuits.

For engineers reviewing the KSA931YTA datasheet, pinout, applications, or equivalent options, key selection criteria include its TO-92L package, −0.7 V VCE(sat) at −500 mA/−50 mA drive, −1.2 V VBE(sat), 100 MHz fT, and guaranteed hFE classification per Fairchild/ON Semi specification Rev. A2.

Technical Context

The KSA931YTA operates as a general-purpose PNP bipolar junction transistor with fixed gain classification (Y = hFE 120–240), optimized for linear amplification and saturated switching in DC-coupled or low-frequency AC signal paths. Its breakdown ratings (VCBO = −80 V, VCEO = −60 V) support operation in moderate-voltage analog rails up to −60 V collector-emitter.

Thermal design relies on its 1 W collector power dissipation rating at 25°C ambient, derating linearly above 25°C per the published power derating curve, and junction temperature limit of 150°C. The device exhibits Cob = 13 pF at VCB = −10 V, supporting stable operation in audio and control-frequency circuits without unintended RF coupling.

Key Specifications

Pinout & Package

Package: TO-92L (lead-form variant of standard TO-92, with longer leads and specific dimensional tolerances per datasheet Rev. A2).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPSA92 and KSA992, the KSA931YTA offers tighter hFE control and optimal balance of voltage rating, saturation performance, and TO-92L manufacturability for mid-power analog and switching roles-making it preferred for cost-sensitive, space-constrained designs requiring production consistency.

Availability

KSA931YTA is available at Aetrix Electronics and suitable for audio preamplifiers, DC motor direction control, power supply error amplifiers, and relay driver interfaces requiring stable component supply and long-term BOM continuity.

Supply support for KSA931YTA 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

ON Semiconductor (formerly Fairchild Semiconductor) is a global semiconductor manufacturer specializing in power management, analog, sensor, and discrete solutions for automotive, industrial, and consumer markets.

The KSA931YTA belongs to ON Semiconductor's legacy general-purpose bipolar transistor product line, engineered for reliability and consistency in linear amplification and medium-speed switching across industrial control and power electronics applications.

FAQ

What is the hFE classification for KSA931YTA?

The KSA931YTA is classified as Class Y, meaning its DC current gain (hFE) is guaranteed between 120 and 240 when measured at VCE = −2 V and IC = −50 mA. This binning ensures predictable base drive requirements and supports consistent performance across production units of the KSA931YTA in both amplification and switching roles.

Is KSA931YTA pin-compatible with other TO-92 PNP transistors like MPSA92?

No-while both KSA931YTA and MPSA92 use TO-92 packages, their pinouts differ: KSA931YTA follows E-C-B (Emitter–Collector–Base) order in TO-92L, whereas MPSA92 uses E-B-C. Using them interchangeably without verifying pin mapping will result in circuit malfunction. Always confirm pinout from official ON Semiconductor documentation for each KSA931YTA unit.

Can KSA931YTA be used in place of KSA931OTA or KSA931RTA?

Yes-KSA931YTA, KSA931OTA, and KSA931RTA are identical in electrical specifications and package; only the hFE bin differs (Y = 120–240, O = 70–140, R = 40–80). Substituting KSA931YTA for lower-gain variants is acceptable if circuit gain margin permits, but may require recalculating base resistors to avoid overdrive or thermal stress in the KSA931YTA.

What is the maximum safe operating temperature for KSA931YTA?

The KSA931YTA has a maximum junction temperature (TJ) of 150°C and a storage temperature range of −55°C to +150°C. For reliable long-term operation, keep the junction temperature below 130°C under continuous load; this requires appropriate PCB copper area, ambient derating, and verification using the published power derating curve in the KSA931YTA datasheet.

Does KSA931YTA support switching speeds suitable for PWM motor control?

The KSA931YTA has an fT of 100 MHz and typical switching times in the hundreds of nanoseconds, making it suitable for PWM motor control up to ~20 kHz-well within audio frequency range. However, it is not optimized for high-frequency SMPS or Class-D audio; for >50 kHz operation, consider faster-switching alternatives while retaining the KSA931YTA for gate-driving or lower-frequency commutation stages.