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

onsemi BC558C

Name: BC558C
Brand: onsemi
SKU: BC558C
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC558C

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BC558C.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC558C from onsemi is a PNP epitaxial silicon transistor designed for general-purpose switching and linear amplification in low-power analog and digital circuits. It features V_CEO = −30 V, I_C = −100 mA, h_FE = 420–800 (Class C), V_BE(on) ≈ −660 mV at I_C = −2 mA, and f_T = 150 MHz - enabling use in audio preamplifiers, level shifters, and discrete logic interfaces.

For engineers reviewing the BC558C datasheet, pinout, applications, or equivalent options, key selection considerations include its TO-92-3 package compatibility, complementary pairing with BC548C, low-noise suitability for signal conditioning stages, and Class C h_FE consistency across production lots.

Technical Context

The BC558C operates as a medium-speed, low-voltage PNP bipolar junction transistor optimized for DC-coupled gain stages and saturated switching. Its h_FE classification (420–800) ensures predictable current amplification under I_C = −2 mA to −10 mA bias, while V_CE(sat) ≤ −300 mV at I_C = −10 mA / I_B = −0.5 mA supports efficient on-state conduction.

Thermal design is constrained by R_JA = 250 °C/W and P_D = 500 mW at T_A = 25 °C, with derating of 4.0 mW/°C above ambient. Its Cob = 6 pF at V_CB = −10 V enables stable operation up to mid-VHF frequencies without unintended resonance in common-emitter configurations.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−30 V: Maximum safe collector-emitter reverse voltage before breakdown in common-emitter configuration.
I_C (DC)	−100 mA: Continuous collector current rating defining maximum linear or switching load drive capability.
h_FE (Class C)	420–800: Guaranteed DC current gain range at V_CE = −5 V, I_C = −2 mA - ensures consistent biasing in amplifier designs.
f_T	150 MHz: Unity-gain bandwidth confirming usable small-signal amplification up to ~15 MHz with reasonable gain margin.
V_BE(on)	−660 mV (typ): Base-emitter turn-on voltage at I_C = −2 mA - critical for accurate bias network calculation in emitter-follower or common-emitter stages.
C_ob	6 pF: Output capacitance at V_CB = −10 V - limits high-frequency stability and affects Miller-effect phase shift in gain stages.

Pinout & Package

BC558C is housed in a TO-92-3 plastic package (Case 135AR), with leads arranged in straight or lead-formed configuration. Pin 1 is Collector, Pin 2 is Base, Pin 3 is Emitter - verified per onsemi mechanical drawing 98AON13879G and marking diagram.

Pin/Terminal	Circuit Role	Design Meaning
1 (Collector)	Current sink terminal	Connected to most negative potential in circuit; carries full load current in switching mode or sets Q-point in amplification.
2 (Base)	Control input	Receives forward-biased current to modulate collector current; requires series resistor to limit I_B and ensure saturation or linear operation.
3 (Emitter)	Current source terminal	Typically tied to ground or positive rail in PNP configuration; provides reference for V_BE bias and defines emitter degeneration if resistively decoupled.

Key Features

Feature	Design Value
Complementary pairing	Matched performance with BC548C NPN - enables balanced push-pull output stages and differential amplifiers without gain mismatch.
Low-noise operation	NF = 2–10 dB at 1 kHz (I_C = −200 µA, R_G = 2 kΩ) - suitable for microphone preamps and sensor signal conditioning where SNR matters.
Pb-free & RoHS compliant	Fully compliant with EU RoHS Directive 2011/65/EU and halogen-free/BFR-free construction - meets industrial and consumer environmental compliance requirements.
High h_FE consistency	Class C binning (420–800) reduces need for post-manufacture gain sorting in production assemblies - lowers test cost and improves yield predictability.

Applications

Audio Preamp Stage	Discrete Logic Level Shifter
Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors in battery-powered voice recorders. IC Role / Device Role / Timing Role: PNP small-signal amplifier in common-emitter configuration with emitter degeneration for linearity and thermal stability. Use Value: V_BE(on) ≈ −660 mV and h_FE ≥ 420 enable stable 20–20 kHz gain > 100 with <1% THD at 100 µA quiescent current.	Use Scenario: Translating 5 V TTL logic outputs to −3 V control inputs in legacy analog power supply sequencers. IC Role / Device Role / Timing Role: Saturated PNP switch operating between cutoff and V_CE(sat) ≤ −300 mV to invert and shift logic levels. Use Value: I_C = −100 mA rating and fast f_T = 150 MHz allow clean edge transitions with <50 ns propagation delay into 10 kΩ loads.
LED Driver (Low-Side)	Current Mirror Reference
Use Scenario: Driving indicator LEDs from microcontroller GPIO pins configured as open-drain with pull-up to −5 V rail. IC Role / Device Role / Timing Role: PNP current sink controlling LED anode connection to negative supply, with base driven by MCU output. Use Value: V_CEO = −30 V safely accommodates −5 V rail plus transient spikes; V_CE(sat) ≤ −250 mV minimizes power loss in 20 mA LED paths.	Use Scenario: Building matched current sources in analog front-ends for sensor excitation or DAC output buffering. IC Role / Device Role / Timing Role: One side of a two-transistor current mirror, leveraging h_FE consistency and low I_CBO = −15 nA for stable ratio accuracy. Use Value: ICBO ≤ −15 nA and tight h_FE binning reduce mirror error to <0.5% over temperature, supporting precision 12-bit analog systems.

Audio Preamp Stage

Discrete Logic Level Shifter

Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors in battery-powered voice recorders.

IC Role / Device Role / Timing Role: PNP small-signal amplifier in common-emitter configuration with emitter degeneration for linearity and thermal stability.

Use Value: V_BE(on) ≈ −660 mV and h_FE ≥ 420 enable stable 20–20 kHz gain > 100 with <1% THD at 100 µA quiescent current.

Use Scenario: Translating 5 V TTL logic outputs to −3 V control inputs in legacy analog power supply sequencers.

IC Role / Device Role / Timing Role: Saturated PNP switch operating between cutoff and V_CE(sat) ≤ −300 mV to invert and shift logic levels.

Use Value: I_C = −100 mA rating and fast f_T = 150 MHz allow clean edge transitions with <50 ns propagation delay into 10 kΩ loads.

LED Driver (Low-Side)

Current Mirror Reference

Use Scenario: Driving indicator LEDs from microcontroller GPIO pins configured as open-drain with pull-up to −5 V rail.

IC Role / Device Role / Timing Role: PNP current sink controlling LED anode connection to negative supply, with base driven by MCU output.

Use Value: V_CEO = −30 V safely accommodates −5 V rail plus transient spikes; V_CE(sat) ≤ −250 mV minimizes power loss in 20 mA LED paths.

Use Scenario: Building matched current sources in analog front-ends for sensor excitation or DAC output buffering.

IC Role / Device Role / Timing Role: One side of a two-transistor current mirror, leveraging h_FE consistency and low I_CBO = −15 nA for stable ratio accuracy.

Use Value: ICBO ≤ −15 nA and tight h_FE binning reduce mirror error to <0.5% over temperature, supporting precision 12-bit analog systems.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC557C	V_CEO = −45 V (vs. −30 V); same h_FE Class C, identical TO-92-3 package and pinout.	Higher voltage headroom allows use in −40 V supply rails or with larger safety margins in industrial controls.	Select BC557C when V_CEO derating is required beyond −30 V; otherwise BC558C offers tighter V_CE(sat) at low I_C.
MMBT558	SOT-23 surface-mount package; same electrical specs but lower P_D = 350 mW and higher R_JA = 300 °C/W.	Enables PCB space reduction and automated assembly but requires thermal relief pads for >50 mA continuous operation.	Choose MMBT558 only for space-constrained boards where reflow compatibility and footprint size outweigh thermal trade-offs.

Compared with BC557C and MMBT558, the BC558C delivers optimal balance of voltage rating, gain consistency, and thermal performance in through-hole prototyping and low-volume industrial assemblies - especially where manual soldering or legacy board layouts constrain package choice.

Availability

BC558C is available at Aetrix Electronics and suitable for audio preamplifiers, discrete logic level shifters, and LED driver circuits requiring stable component supply, long-term obsolescence management, and RoHS-compliant sourcing.

Supply support for BC558C 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 management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The BC558C belongs to onsemi's legacy BC5xx PNP/NPN transistor family - engineered for reliability, manufacturability, and broad compatibility in discrete analog signal chains and power interface circuits.

FAQ

What is the maximum collector-emitter voltage rating for BC558C?

The BC558C has a guaranteed V_CEO rating of −30 V at T_A = 25 °C. This specifies the maximum reverse voltage that can be applied between collector and emitter with the base open before breakdown occurs. Exceeding this value risks permanent device damage, and derating is recommended for operation above 25 °C ambient or under pulsed conditions. The BC558C datasheet confirms this parameter in the Absolute Maximum Ratings table.

Is BC558C pin-compatible with BC557C and BC556B?

Yes, BC558C shares identical TO-92-3 package (Case 135AR), pin assignment (Collector-Base-Emitter), and mechanical dimensions with BC557C and BC556B. All three use Pin 1 = Collector, Pin 2 = Base, Pin 3 = Emitter. However, their V_CEO and V_CBO ratings differ: BC556B = −65 V, BC557C = −45 V, BC558C = −30 V - so substitution requires verification of voltage stress in the target circuit.

What h_FE range does BC558C guarantee, and how is it binned?

The BC558C is binned to h_FE Class C, guaranteeing a DC current gain of 420 to 800 when measured at V_CE = −5 V and I_C = −2 mA. This classification is laser-marked as "C" on the device body and confirmed in the h_FE Classification table of the onsemi BC556–BC560 datasheet. It enables predictable biasing without post-production gain sorting.

Can BC558C be used as a direct replacement for BC558B in existing designs?

Yes, BC558C is a functional upgrade to BC558B with identical package, pinout, and absolute maximum ratings - but offers higher guaranteed h_FE (420–800 vs. 200–450 for Class B). No PCB or schematic changes are needed; improved gain may reduce base drive requirements or improve noise performance in amplifier stages using BC558C.

Does BC558C meet modern environmental compliance standards?

Yes, BC558C 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 official onsemi datasheet and verified via material declarations. It supports compliance for industrial, medical, and consumer products sold in regulated markets.

BC558C 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):: 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

BC558C FAQ

1.How can I place an order for BC558C through Aetrix?

Please submit a Request for Quotation (RFQ) for BC558C 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 BC558C reliable?

The price and inventory of BC558C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC558C is usually 5 days.

3.What payment methods are accepted for BC558C?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC558C transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC558C?

BC558C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC558C 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 BC558C?

For technical support, including BC558C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC558C requirements.

6.How does Aetrix verify that BC558C is sourced from the original manufacturer or authorized distributors?

All BC558C 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 BC558C meets industry standards.

7.What is the process for return or replacement of BC558C?

All BC558C units undergo pre-shipment inspection (PSI). If there is an issue with BC558C, 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 BC558C part is unused and in its original packaging.

Return procedure for BC558C:

1.Submit a request within 90 days.

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

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