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

onsemi BC558CTA

Name: BC558CTA
Brand: onsemi
SKU: BC558CTA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC558CTA

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC558CTA.pdf

Description:: TRANS PNP 30V 0.1A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC558CTA from onsemi is a PNP epitaxial silicon transistor designed for general-purpose switching and linear amplification in low-to-medium power circuits. It features V_CEO = −30 V, I_C = −100 mA, h_FE = 420–800 (Class C), V_CE(sat) ≤ −650 mV at I_C = −100 mA, and operates up to 150 °C junction temperature - commonly used in discrete logic inverters, LED drivers, and signal-level audio preamplifiers.

For engineers reviewing the BC558CTA datasheet, pinout, applications, or equivalent options, key selection criteria include its TO-92-3 package compatibility, Class C DC current gain range, −30 V collector-emitter breakdown rating, low-noise capability relative to BC556/BC557 variants, and complementarity with BC546–BC550 NPN series in push-pull stages.

Technical Context

The BC558CTA is a discrete PNP bipolar junction transistor optimized for linear amplification and saturated switching. Its h_FE classification (C: 420–800) ensures consistent current gain across production lots under V_CE = −5 V and I_C = −2 mA conditions, while its −30 V V_CEO rating defines safe operation in low-voltage negative-rail applications.

Thermal performance is characterized by R_JA = 250 °C/W and 500 mW maximum dissipation at 25 °C, derating at 4.0 mW/°C above ambient - requiring minimal heatsinking in PCB-mounted TO-92 configurations. Its f_T = 150 MHz supports audio-frequency amplification and fast-switching digital interfaces up to ~10 MHz.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−30 V: Maximum allowable collector-emitter voltage before breakdown in common-emitter configuration.
I_C (DC)	−100 mA: Continuous collector current limit defining safe linear or switching operation without thermal runaway.
h_FE (Class C)	420–800: Guaranteed DC current gain range at V_CE = −5 V, I_C = −2 mA - enables predictable biasing in amplifier designs.
V_CE(sat)	≤ −650 mV at I_C = −100 mA, I_B = −5 mA: Low saturation voltage ensures minimal power loss in switching applications.
f_T	150 MHz: Current gain bandwidth product indicating usable small-signal amplification up to mid-VHF frequencies.
C_ob	6 pF at V_CB = −10 V: Output capacitance affecting high-frequency response and stability in RF-coupled stages.

Pinout & Package

BC558CTA is housed in a TO-92-3 plastic package (Case 135AR), lead-formed for through-hole mounting. Dimensions: 4.83 mm × 4.76 mm × 3.6 mm. Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter - verified per onsemi mechanical drawing 98AON13879G.

Pin/Terminal	Circuit Role	Design Meaning
1 (Collector)	Main current sink terminal	Connected to negative supply rail or load return path; handles full output current in common-emitter switches.
2 (Base)	Control input node	Receives forward-biased current to drive transistor into active or saturation region; requires current-limiting resistor in most designs.
3 (Emitter)	Current source reference	Typically tied to ground or positive rail in PNP configurations; establishes reference for V_BE biasing and emitter-follower output.

Key Features

Feature	Design Value
Complementary pairing	Designed as direct PNP counterpart to BC546–BC550 NPN transistors - enables matched push-pull, differential pair, and complementary symmetry circuits.
Low-noise amplification	Specified NF = 2–10 dB at 1 kHz (V_CE = −5 V, I_C = −200 µA, R_G = 2 kΩ), supporting clean signal amplification in sensor front-ends and audio preamps.
Pb-free & RoHS compliance	Meets EU RoHS Directive 2011/65/EU and halogen-free/BFR-free requirements - suitable for environmentally regulated industrial and consumer products.
High-temperature operation	Rated for continuous operation up to T_J = 150 °C - supports reliability in enclosed or thermally constrained environments without forced cooling.

Applications

LED Driver Circuit	Discrete Logic Inverter
Use Scenario: Driving 20 mA indicator LEDs from microcontroller GPIO pins with open-drain or active-low outputs. IC Role / Device Role / Timing Role: PNP switch configured in common-emitter mode, sinking current from LED anode to ground when base is pulled low. Use Value: V_CE(sat) ≤ −650 mV ensures <150 mW dissipation at 20 mA, minimizing self-heating and enabling reliable long-term LED control without external drivers.	Use Scenario: Implementing TTL-compatible NOT gates in legacy analog-digital hybrid systems where IC-level logic is unavailable or cost-prohibitive. IC Role / Device Role / Timing Role: Single-transistor inverter with resistive base bias and collector pull-up, delivering rail-to-rail logic swing with propagation delay <100 ns. Use Value: h_FE ≥ 420 guarantees sufficient drive strength for fan-out of ≥4 standard TTL loads while maintaining noise margins >0.4 V.
Audio Pre-amplifier Stage	Power Supply Enable Switch
Use Scenario: First-stage amplification of microphone or piezoelectric sensor signals in battery-powered portable audio recorders. IC Role / Device Role / Timing Role: Common-emitter amplifier biased in Class A, using emitter degeneration for linearity and thermal stability. Use Value: Low NF (2–10 dB) and f_T = 150 MHz preserve signal integrity up to 20 kHz with <0.5% THD+N at 1 V_PP output into 10 kΩ load.	Use Scenario: Enabling/disabling 5 V or 3.3 V subsystems (e.g., sensors, radios) via MCU-controlled enable lines in embedded power management. IC Role / Device Role / Timing Role: High-side PNP switch controlling V_CC delivery to downstream circuitry, with base driven through current-limiting resistor. Use Value: −30 V V_CEO provides 2× margin over 12 V system rails, and I_C = −100 mA supports typical subsystem loads up to 50 mA with safety headroom.

LED Driver Circuit

Discrete Logic Inverter

Use Scenario: Driving 20 mA indicator LEDs from microcontroller GPIO pins with open-drain or active-low outputs.

IC Role / Device Role / Timing Role: PNP switch configured in common-emitter mode, sinking current from LED anode to ground when base is pulled low.

Use Value: V_CE(sat) ≤ −650 mV ensures <150 mW dissipation at 20 mA, minimizing self-heating and enabling reliable long-term LED control without external drivers.

Use Scenario: Implementing TTL-compatible NOT gates in legacy analog-digital hybrid systems where IC-level logic is unavailable or cost-prohibitive.

IC Role / Device Role / Timing Role: Single-transistor inverter with resistive base bias and collector pull-up, delivering rail-to-rail logic swing with propagation delay <100 ns.

Use Value: h_FE ≥ 420 guarantees sufficient drive strength for fan-out of ≥4 standard TTL loads while maintaining noise margins >0.4 V.

Audio Pre-amplifier Stage

Power Supply Enable Switch

Use Scenario: First-stage amplification of microphone or piezoelectric sensor signals in battery-powered portable audio recorders.

IC Role / Device Role / Timing Role: Common-emitter amplifier biased in Class A, using emitter degeneration for linearity and thermal stability.

Use Value: Low NF (2–10 dB) and f_T = 150 MHz preserve signal integrity up to 20 kHz with <0.5% THD+N at 1 V_PP output into 10 kΩ load.

Use Scenario: Enabling/disabling 5 V or 3.3 V subsystems (e.g., sensors, radios) via MCU-controlled enable lines in embedded power management.

IC Role / Device Role / Timing Role: High-side PNP switch controlling V_CC delivery to downstream circuitry, with base driven through current-limiting resistor.

Use Value: −30 V V_CEO provides 2× margin over 12 V system rails, and I_C = −100 mA supports typical subsystem loads up to 50 mA with safety headroom.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC558BTA	h_FE = 200–450 (Class B); otherwise identical absolute ratings, pinout, and package.	Suitable where moderate gain consistency suffices; lower h_FE reduces risk of unintended oscillation in high-gain feedback loops.	Select BC558BTA when tighter h_FE tolerance is unnecessary and cost optimization is prioritized.
BC557BTA	V_CEO = −45 V, V_CBO = −50 V; h_FE = 200–450; same TO-92-3 package and pinout.	Preferred in higher-voltage rails (e.g., −40 V supplies) where BC558CTA's −30 V rating is insufficient.	Choose BC557BTA when operating beyond −30 V collector-emitter stress but retaining same footprint and bias network.

Compared with BC558BTA and BC557BTA, the BC558CTA offers highest guaranteed h_FE for precision biasing and low-distortion amplification, while BC557BTA extends voltage capability at the expense of gain - enabling trade-offs between linearity, voltage margin, and cost in discrete analog design.

Availability

BC558CTA is available at Aetrix Electronics and suitable for LED driver circuits, discrete logic inverters, audio pre-amplifier stages, and power supply enable switches requiring stable component supply, long-lifecycle support, and RoHS-compliant through-hole transistors.

Supply support for BC558CTA 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, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and IoT applications.

The BC558CTA belongs to onsemi's legacy BC5xx PNP/NPN transistor family, engineered for cost-sensitive, high-reliability discrete analog functions - including signal conditioning, power control, and interface logic in resource-constrained embedded systems.

FAQ

What is the maximum collector-emitter voltage rating for BC558CTA?

The BC558CTA has a maximum collector-emitter voltage (V_CEO) rating of −30 V at T_A = 25 °C. This value is specified in the Absolute Maximum Ratings table of the official onsemi datasheet (Rev. 3, June 2024) and must not be exceeded to prevent device breakdown. Derating applies at elevated ambient temperatures.

Is BC558CTA pin-compatible with other BC5xx series transistors?

Yes, BC558CTA uses the standard TO-92-3 package (Case 135AR) with Collector–Base–Emitter pinout (1–2–3), matching all BC556–BC560 and BC546–BC550 variants. This allows direct physical replacement in existing layouts, though electrical parameters like V_CEO and h_FE differ across the family.

What h_FE classification does BC558CTA have, and how is it tested?

BC558CTA is classified as Class C, with h_FE guaranteed between 420 and 800 when measured at V_CE = −5 V and I_C = −2 mA (TA = 25 °C). This classification is confirmed in the h_FE Classification table on page 2 of the onsemi BC556–BC560 datasheet.

Does BC558CTA meet RoHS and environmental compliance standards?

Yes, BC558CTA is Pb-free, halogen-free/BFR-free, and fully RoHS compliant per EU Directive 2011/65/EU. This is explicitly stated in the Features section of the onsemi datasheet and verified in the Ordering Information table, which lists it as a Pb-free device in TO-92-3 case 135AR.

Can BC558CTA be used in high-frequency amplifier designs?

BC558CTA has an f_T of 150 MHz, making it suitable for audio-frequency amplification and low-speed RF coupling up to ~10 MHz. However, its Cob = 6 pF and gain roll-off characteristics limit use in VHF/UHF or broadband applications - for those, dedicated RF transistors like MMBT918 or BF199 are recommended instead of BC558CTA.

BC558CTA Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Box (TB)

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 100 mA

Voltage - Collector Emitter Breakdown (Max):: 30 V

Vce Saturation (Max) @ Ib, Ic:: 650mV @ 5mA, 100mA

Current - Collector Cutoff (Max):: 15nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 420 @ 2mA, 5V

Power - Max:: 500 mW

Frequency - Transition:: 150MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

BC558CTA FAQ

1.How can I place an order for BC558CTA through Aetrix?

Please submit a Request for Quotation (RFQ) for BC558CTA 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 BC558CTA reliable?

The price and inventory of BC558CTA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC558CTA is usually 5 days.

3.What payment methods are accepted for BC558CTA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC558CTA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC558CTA?

BC558CTA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC558CTA 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 BC558CTA?

For technical support, including BC558CTA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC558CTA requirements.

6.How does Aetrix verify that BC558CTA is sourced from the original manufacturer or authorized distributors?

All BC558CTA 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 BC558CTA meets industry standards.

7.What is the process for return or replacement of BC558CTA?

All BC558CTA units undergo pre-shipment inspection (PSI). If there is an issue with BC558CTA, 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 BC558CTA part is unused and in its original packaging.

Return procedure for BC558CTA:

1.Submit a request within 90 days.

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

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