onsemi KSA931YBU

Overview

KSA931YBU from ON Semiconductor is a PNP epitaxial silicon transistor designed for low-frequency amplification and medium-speed switching applications, with V_CBO = −80 V, V_CEO = −60 V, I_C = −700 mA, P_C = 1 W, and h_FE range of 120–240 (Class Y), housed in a TO-92L package.

For engineers reviewing the KSA931YBU datasheet, pinout, applications, or equivalent options, this device serves as a complement to the NPN KSC2331 in dual-transistor amplifier stages, relay drivers, and power supply control circuits where robust PNP gain and saturation performance are required.

Technical Context

The KSA931YBU operates as a general-purpose PNP bipolar junction transistor with fixed emitter-base and collector-base junction structures optimized for linear amplification and saturated switching. Its DC current gain (h_FE) is specified at V_CE = −2 V and I_C = −50 mA, and its safe operating area supports pulsed operation up to 200 ms at T_A = 25°C.

It features low V_CE(sat) (−0.3 V to −0.7 V at I_C = −500 mA, I_B = −50 mA) and V_BE(sat) (−0.9 V to −1.2 V under same conditions), enabling efficient current sourcing in grounded-load configurations. Cob = 13 pF at V_CB = −10 V ensures stable behavior in audio-frequency signal paths.

Key Specifications

Pinout & Package

Package: TO-92L - 3-lead through-hole plastic package with 2.54 mm lead pitch, 4.90 mm body length, and 1.70 mm body width; optimized for manual assembly and board-level reliability in non-high-frequency layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD2955G and KSA992FBU, the KSA931YBU uniquely balances medium-voltage tolerance (−60 V), medium-current capability (−700 mA), and high-gain consistency (120–240) in the compact TO-92L form factor-making it optimal for cost-sensitive, space-limited industrial control and audio signal conditioning where both voltage headroom and gain predictability are required.

Availability

KSA931YBU is available at Aetrix Electronics and suitable for audio preamplifiers, relay drivers, DC power supply control, and industrial sensor interfaces requiring stable component supply and long-term manufacturing continuity.

Supply support for KSA931YBU 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 is a global semiconductor manufacturer specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The KSA931YBU belongs to ON Semiconductor's general-purpose bipolar transistor product line, engineered for reliable low-frequency amplification and medium-speed switching in cost-sensitive industrial and consumer electronics.

FAQ

What is the maximum collector-emitter voltage rating for KSA931YBU?

The KSA931YBU has a maximum collector-emitter voltage (V_CEO) rating of −60 V at T_A = 25°C. This rating applies under open-base conditions and defines the upper limit of reverse voltage the transistor can block in common-emitter configurations. Exceeding this value risks avalanche breakdown and permanent device failure. Derating is required above 25°C ambient per the power derating curve in the datasheet.

How does the h_FE classification "Y" affect KSA931YBU design usage?

The "Y" suffix in KSA931YBU indicates a factory-binned h_FE range of 120–240 measured at V_CE = −2 V and I_C = −50 mA. This tight gain grouping allows designers to size base resistors with higher confidence and reduces unit-to-unit variation in amplifier gain or switch turn-on time. It is distinct from "R" (40–80) and "O" (70–140) variants, making KSA931YBU preferred for applications demanding predictable current amplification.

Can KSA931YBU be used as a direct replacement for KSA931RBU or KSA931OBU?

No, KSA931YBU is not a direct replacement for KSA931RBU or KSA931OBU due to differing h_FE ranges: R = 40–80, O = 70–140, Y = 120–240. Substituting without circuit revalidation may cause insufficient base drive (in R/O versions) or excessive base current (in Y version), leading to thermal stress or unstable bias points. Always verify h_FE-dependent calculations when swapping between KSA931 variants.

What is the safe operating area (SOA) limitation for KSA931YBU in pulsed applications?

The KSA931YBU SOA supports single-pulse operation up to 200 ms at T_A = 25°C, with maximum I_C decreasing as V_CE increases. For example, at V_CE = −30 V, the absolute maximum pulsed I_C is approximately −350 mA. Continuous DC operation is limited to −700 mA only at V_CE ≤ −2 V; higher V_CE requires proportional current reduction to stay within the 1 W power envelope.

Is KSA931YBU RoHS compliant and halogen-free?

Yes, KSA931YBU is RoHS compliant and halogen-free per ON Semiconductor's product change notices and material declarations. The device meets EU Directive 2011/65/EU and subsequent amendments, with lead content below 1000 ppm and bromine/chlorine content below 900 ppm per homogeneous material. Full compliance documentation is available via ON Semiconductor's Quality & Environmental page.