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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi KSA733YBU

Name: KSA733YBU
Brand: onsemi
SKU: KSA733YBU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: KSA733YBU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA)

Datasheet:: KSA733YBU.pdf

Description:: TRANS PNP 50V 0.15A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

KSA733YBU from ON Semiconductor is a PNP epitaxial silicon transistor designed for low-frequency amplifier and switching applications, with confirmed V_CEO = −50 V, I_C = −150 mA, P_C = 250 mW, h_FE range of 350–700 (Y-grade), and f_T up to 180 MHz. It features TO-92 package, complementarity to KSC945, and is commonly used in audio preamplifier stages and signal-level switching circuits.

For engineers reviewing the KSA733YBU datasheet, pinout, applications, or equivalent options, key selection criteria include verified DC current gain classification (Y-grade), collector-emitter saturation voltage under defined drive conditions, noise figure at 1 MHz, output capacitance, and thermal limits for continuous operation in discrete analog designs.

Technical Context

This PNP bipolar junction transistor operates in active, saturation, and cutoff regions with defined breakdown voltages (V_CBO = −60 V, V_CEO = −50 V, V_EBO = −5 V) and leakage currents (I_CBO ≤ −100 nA, I_EBO ≤ −100 nA). Its h_FE is specified at V_CE = −6 V and I_C = −1 mA, supporting stable DC biasing in linear amplification.

The device exhibits V_CE(sat) = −0.18 to −0.3 V at I_C = −100 mA / I_B = −10 mA, enabling efficient low-voltage switching, and delivers f_T = 50–180 MHz - sufficient for audio and sub-MHz signal conditioning. Cob = 2.8 pF at V_CB = −10 V confirms suitability for low-noise, low-capacitance node interfacing.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−50 V: Maximum safe collector-emitter reverse bias before breakdown in common-emitter configuration.
I_C	−150 mA: Continuous DC collector current rating; defines maximum signal swing capability in amplifier or switch mode.
h_FE (Y-grade)	350–700: Verified DC current gain range at V_CE = −6 V, I_C = −1 mA; ensures predictable base drive requirements.
f_T	50–180 MHz: Current gain–bandwidth product; supports stable small-signal amplification up to ~100 MHz with gain margin.
V_CE(sat)	−0.18 to −0.3 V at I_C = −100 mA / I_B = −10 mA: Low saturation voltage enables minimal power loss in switching applications.
C_ob	2.8 pF at V_CB = −10 V, f = 1 MHz: Low output capacitance minimizes high-frequency loading and phase shift in amplifier feedback paths.
NF	6.0–20 dB at V_CE = −6 V, I_C = −0.3 mA, f = 1 MHz, R_s = 10 kΩ: Confirmed noise performance for low-level analog signal amplification.

Pinout & Package

Package: TO-92, through-hole, 3-lead plastic case with standardized lead assignment per JEDEC TO-92 outline. Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector (suffix "-C" denotes center-collector variant; KSA733YBU uses standard pinout: 1–E, 2–B, 3–C).

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current exit terminal in PNP operation	Connected to most positive rail in common-emitter amplifier; sets reference for base bias network.
2 (Base)	Control electrode for minority-carrier injection	Receives forward-biased current to modulate collector current; requires current-limiting resistor in discrete biasing.
3 (Collector)	Current entry terminal in PNP operation	Typically tied to load or supply rail; voltage swing here defines output dynamic range in amplifier stage.

Key Features

Feature	Design Value
Y-grade h_FE binning	Guaranteed 350–700 h_FE at test condition, enabling consistent gain matching in multi-stage amplifiers without individual trimming.
Low V_CE(sat)	−0.18 V typical at rated I_C/I_B, reducing conduction loss and self-heating in saturated-switch applications.
Complementary pairing	Designed as direct PNP counterpart to NPN KSC945, simplifying push-pull and differential pair implementation.
Low noise figure	6.0 dB minimum at 1 MHz supports high-fidelity preamplification of weak signals (e.g., microphone, sensor outputs).

Applications

Audio Preamp Stage	Signal-Level Switch
Use Scenario: Amplifying low-amplitude microphone or piezoelectric sensor output prior to ADC sampling. IC Role / Device Role / Timing Role: Discrete PNP transistor configured in common-emitter topology for voltage gain and impedance transformation. Use Value: Y-grade h_FE ensures predictable gain stability across units; low NF preserves SNR in first amplification stage.	Use Scenario: Enabling/disabling a 12 V analog sensor supply rail using microcontroller GPIO. IC Role / Device Role / Timing Role: Saturated PNP switch controlling current path between supply and load. Use Value: V_CE(sat) ≤ −0.3 V minimizes voltage drop and power dissipation (< 30 mW at 100 mA), improving efficiency.
Differential Pair Input	Current Mirror Load
Use Scenario: Forming input stage of discrete op-amp or instrumentation amplifier with matched gain transistors. IC Role / Device Role / Timing Role: One side of complementary emitter-coupled pair with KSC945. Use Value: Matched h_FE binning (Y-grade) and low Cob reduce gain error and improve CMRR at audio frequencies.	Use Scenario: Providing active load in high-gain CE amplifier for improved linearity and bandwidth. IC Role / Device Role / Timing Role: Constant-current sink configured via base bias network. Use Value: High V_CEO (−50 V) allows operation with elevated collector supply rails; low I_CBO ensures stable reference current.

Audio Preamp Stage

Signal-Level Switch

Use Scenario: Amplifying low-amplitude microphone or piezoelectric sensor output prior to ADC sampling.

IC Role / Device Role / Timing Role: Discrete PNP transistor configured in common-emitter topology for voltage gain and impedance transformation.

Use Value: Y-grade h_FE ensures predictable gain stability across units; low NF preserves SNR in first amplification stage.

Use Scenario: Enabling/disabling a 12 V analog sensor supply rail using microcontroller GPIO.

IC Role / Device Role / Timing Role: Saturated PNP switch controlling current path between supply and load.

Use Value: V_CE(sat) ≤ −0.3 V minimizes voltage drop and power dissipation (< 30 mW at 100 mA), improving efficiency.

Differential Pair Input

Current Mirror Load

Use Scenario: Forming input stage of discrete op-amp or instrumentation amplifier with matched gain transistors.

IC Role / Device Role / Timing Role: One side of complementary emitter-coupled pair with KSC945.

Use Value: Matched h_FE binning (Y-grade) and low Cob reduce gain error and improve CMRR at audio frequencies.

Use Scenario: Providing active load in high-gain CE amplifier for improved linearity and bandwidth.

IC Role / Device Role / Timing Role: Constant-current sink configured via base bias network.

Use Value: High V_CEO (−50 V) allows operation with elevated collector supply rails; low I_CBO ensures stable reference current.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MPSA92	V_CEO = −300 V, h_FE = 50–250 (unbinned), P_C = 625 mW, TO-92	Higher voltage rating but lower and unbinned h_FE; less suitable for gain-critical low-noise preamps.	Select when higher breakdown voltage is required and gain consistency is secondary.
BC557B	V_CEO = −45 V, h_FE = 200–450 (B-grade), P_C = 500 mW, TO-92	Lower max h_FE, higher power rating, slightly reduced V_CEO; broader h_FE spread affects bias stability.	Prefer when higher power dissipation is needed and Y-grade gain tightness is not mandatory.

Compared with MPSA92 and BC557B, KSA733YBU offers tighter h_FE control (350–700), lower noise, and optimized f_T for audio-frequency amplification - making it preferable where gain predictability and signal fidelity are prioritized over extreme voltage or power handling.

Availability

KSA733YBU is available at Aetrix Electronics and suitable for audio preamplifier design, discrete switching circuits, and differential pair implementations requiring stable component supply and consistent Y-grade h_FE performance.

Supply support for KSA733YBU 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, and discrete components for automotive, industrial, and consumer applications.

KSA733YBU belongs to ON Semiconductor's legacy Fairchild discrete transistor portfolio, engineered specifically for cost-sensitive, high-reliability low-frequency analog signal conditioning and general-purpose switching.

FAQ

What is the pin configuration of KSA733YBU?

KSA733YBU uses the standard TO-92 pinout: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector. This matches the JEDEC TO-92 outline and is explicitly confirmed in the Fairchild KSA733 datasheet Rev. A2. The suffix "Y" denotes h_FE binning (350–700), not pinout variation. No center-collector ("-C") variant applies to KSA733YBU.

What does the "Y" suffix mean in KSA733YBU?

The "Y" suffix in KSA733YBU specifies the h_FE (DC current gain) bin: 350–700 at V_CE = −6 V and I_C = −1 mA. This grading ensures tighter gain distribution than standard "R", "O", or "G" bins, supporting repeatable biasing in production amplifier designs without manual selection.

Is KSA733YBU a direct replacement for KSA733Y?

Yes - KSA733YBU is the updated ON Semiconductor part number for the legacy Fairchild KSA733Y. Per ON Semiconductor's Fairchild integration notice, underscores were replaced with dashes; "KSA733Y_BU" became "KSA733YBU". Electrical specs, package, and binning remain identical, and KSA733YBU is the currently orderable version.

What is the maximum operating temperature for KSA733YBU?

KSA733YBU 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 linearly reduced by 2.0 mW/°C above 25°C to maintain T_J ≤ 150°C, based on its 250 mW rated P_C and thermal resistance characteristics.

How does KSA733YBU compare to its NPN complement KSC945?

KSA733YBU and KSC945 form a matched complementary pair: same TO-92 package, symmetric voltage ratings (KSC945: V_CEO = +50 V), and closely aligned h_FE ranges (KSC945Y: 350–700). This enables balanced push-pull output stages, differential amplifiers, and current mirrors where PNP/NPN symmetry improves linearity and reduces distortion in KSA733YBU-based designs.

KSA733YBU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA)

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 150 mA

Voltage - Collector Emitter Breakdown (Max):: 50 V

Vce Saturation (Max) @ Ib, Ic:: 300mV @ 10mA, 100mA

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 120 @ 1mA, 6V

Power - Max:: 250 mW

Frequency - Transition:: 180MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

KSA733YBU FAQ

1.How can I place an order for KSA733YBU through Aetrix?

Please submit a Request for Quotation (RFQ) for KSA733YBU on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for KSA733YBU reliable?

The price and inventory of KSA733YBU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSA733YBU is usually 5 days.

3.What payment methods are accepted for KSA733YBU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSA733YBU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for KSA733YBU?

KSA733YBU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your KSA733YBU order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for KSA733YBU?

For technical support, including KSA733YBU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSA733YBU requirements.

6.How does Aetrix verify that KSA733YBU is sourced from the original manufacturer or authorized distributors?

All KSA733YBU products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that KSA733YBU meets industry standards.

7.What is the process for return or replacement of KSA733YBU?

All KSA733YBU units undergo pre-shipment inspection (PSI). If there is an issue with KSA733YBU, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The KSA733YBU part is unused and in its original packaging.

Return procedure for KSA733YBU:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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