onsemi KSA733CYTA

Overview

KSA733CYTA from ON Semiconductor is a PNP epitaxial silicon transistor designed for low-frequency amplification and switching applications, with V_CEO = −50 V, I_C = −150 mA, P_C = 250 mW, h_FE range of 350–700 (Y-class), and TO-92 package. It serves as a complement to the NPN KSC945 in push-pull amplifier stages and discrete logic interfaces.

For engineers reviewing the KSA733CYTA datasheet, pinout, applications, or equivalent options, key selection criteria include its Y-class h_FE binning, −0.18 V typical V_CE(sat) at −100 mA/−10 mA drive, low noise figure (6–20 dB), and TO-92 mechanical compatibility in space-constrained analog signal paths.

Technical Context

The KSA733CYTA operates as a general-purpose PNP bipolar junction transistor with fixed-emitter biasing capability and DC-coupled gain staging. Its h_FE classification (Y) guarantees minimum DC current gain of 350 at V_CE = −6 V and I_C = −1 mA, supporting stable biasing in Class-A audio preamplifiers and level-shifting circuits.

It features low output capacitance (C_ob = 2.8 pF at V_CB = −10 V), enabling use in <10 MHz signal conditioning without significant high-frequency roll-off. The f_T of 50–180 MHz confirms suitability for narrowband RF front-end buffering where linearity and low noise outweigh wideband requirements.

Key Specifications

Pinout & Package

Package: TO-92 (3-lead plastic through-hole), lead configuration: Emitter–Base–Collector (1–2–3), body diameter 3.60 mm max, total length 4.58 mm, lead pitch 1.27 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with KSA733OTA and MPSA92, the KSA733CYTA delivers optimal trade-off between high, binned gain (350–700), low saturation loss, and low-noise performance-making it preferred for precision analog amplification and compact switching where gain consistency and thermal efficiency are critical.

Availability

KSA733CYTA is available at Aetrix Electronics and suitable for audio preamplifier stages, discrete logic level shifters, relay driver circuits, and LED current sink applications requiring stable component supply and long-term manufacturability.

Supply support for KSA733CYTA 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 KSA733CYTA belongs to ON Semiconductor's legacy general-purpose bipolar transistor portfolio, originally developed by Fairchild Semiconductor to serve cost-sensitive, reliability-critical analog and discrete logic applications in industrial controls and consumer electronics.

FAQ

What does the "Y" suffix in KSA733CYTA indicate?

The "Y" in KSA733CYTA denotes the h_FE gain bin: guaranteed 350–700 at V_CE = −6 V and I_C = −1 mA. This binning ensures predictable DC biasing in amplifier and switching circuits without post-manufacturing gain screening. The full part number KSA733CYTA reflects this specific gain classification, distinguishing it from O-, R-, or G-class variants.

Is KSA733CYTA pin-compatible with KSC945?

No-KSA733CYTA (PNP) and KSC945 (NPN) are complementary devices but have opposite polarity and reversed pinouts: KSA733CYTA is E-B-C (1-2-3), while KSC945 is E-C-B (1-2-3). They are intended for matched-pair use in push-pull topologies, not direct substitution. Always verify pin mapping before board layout or replacement.

What is the maximum operating temperature for KSA733CYTA?

The KSA733CYTA has a maximum junction temperature (T_J) of 150°C and storage temperature range of −55°C to +150°C. Derating is required above 25°C ambient: power dissipation must be reduced linearly beyond 25°C at 2.0 mW/°C per the datasheet thermal resistance spec. Thermal design must account for TO-92's inherent limitations in convection cooling.

Can KSA733CYTA be used in RF applications?

KSA733CYTA has an f_T of 50–180 MHz and C_ob of 2.8 pF, making it usable in narrowband RF applications below 10 MHz-such as IF amplifiers or low-frequency oscillator buffers-where low noise and gain stability matter more than wide bandwidth. It is not rated for HF/VHF power amplification or high-speed digital switching.

Does KSA733CYTA require a heatsink in normal operation?

No-KSA733CYTA's 250 mW power dissipation rating and TO-92 package are sufficient for operation at ≤100 mA collector current with ambient temperatures ≤50°C and no forced airflow. Heatsinking is unnecessary unless operating continuously near P_C max with elevated ambient or poor PCB copper area; thermal simulation is advised for sustained >150 mW loads.