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

onsemi BC557BRL1G

Name: BC557BRL1G
Brand: onsemi
SKU: BC557BRL1G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC557BRL1G

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 Long Body, Formed Leads

Datasheet:: BC557BRL1G.pdf

Description:: TRANS PNP 45V 0.1A TO92

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC557BRL1G from onsemi is a PNP silicon small-signal amplifier transistor in TO-92 package, rated for −45 V V_CEO, −50 V V_CBO, −5.0 V V_EBO, −100 mA I_C, and 625 mW P_D at T_A = 25°C. It delivers h_FE = 220–460 at I_C = −2 mA, V_CE = −5 V, and f_T = 320 MHz, commonly used in low-noise audio preamplifiers and discrete logic-level shifting circuits.

For engineers reviewing the BC557BRL1G datasheet, pinout, applications, or equivalent options, this page provides verified electrical parameters, TO-92 terminal mapping, thermal resistance values (R_JA = 200°C/W), noise figure (NF = 2.0 dB), and validated alternative transistors for biasing, switching, and amplification designs.

Technical Context

The BC557BRL1G operates as a general-purpose PNP bipolar junction transistor optimized for linear amplification and medium-speed switching. Its DC current gain (h_FE) is specified across three test conditions: −10 mA, −2 mA, and −100 mA collector currents, with corresponding V_CE = −5 V and temperature-controlled test environment (T_A = 25°C).

It features low saturation voltage (V_CE(sat) = −0.25 V max at I_C = −10 mA, I_B = −0.5 mA), tight V_BE(on) range (−0.62 to −0.7 V), and stable small-signal gain (h_fe = 260–500 at I_C = −2 mA). Junction-to-ambient thermal resistance is 200°C/W, supporting reliable operation up to +150°C junction temperature.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−45 V - Maximum allowable collector-emitter voltage before breakdown under open-base condition; defines safe operating voltage headroom in PNP common-emitter stages.
h_FE @ I_C = −2 mA	220–460 - Confirmed DC current gain range at low-current bias point; enables predictable base drive sizing for low-power amplifiers and sensor interfaces.
f_T	320 MHz - Transition frequency at I_C = −10 mA, V_CE = −5 V; supports audio-frequency amplification and sub-MHz switching applications.
NF	2.0 dB - Noise figure measured at I_C = −0.2 mA, V_CE = −5 V, R_S = 2 kΩ, 1 kHz; suitable for low-noise preamp stages in microphone and sensor signal chains.
R_JA	200°C/W - Junction-to-ambient thermal resistance in free-air; determines required heatsinking or PCB copper area for continuous 625 mW dissipation at ambient ≤ 25°C.
C_ob	3.0–6.0 pF - Output capacitance at V_CB = −10 V; impacts high-frequency bandwidth limitation and stability in tuned amplifier designs.

Pinout & Package

BC557BRL1G uses the TO-92 (Case 29, Style 17) package with bent leads and Pb-free finish. Dimensions conform to JEDEC TO-226 standard: body height 4.45–5.20 mm, lead pitch 2.54 mm, and maximum lead length 6.35 mm.

Pin/Terminal	Circuit Role	Design Meaning
1 (Collector)	Main current sink terminal	Connected to most negative supply rail in PNP amplifier/switch configurations; carries full load current and requires thermal consideration.
2 (Base)	Control input node	Receives reverse-biased current to turn device ON; requires current-limiting resistor to prevent overdrive and ensure h_FE-based bias stability.
3 (Emitter)	Current source terminal	Typically tied to system ground or positive rail in PNP circuits; serves as reference for V_BE biasing and sets emitter degeneration impedance.

Key Features

Feature	Design Value
Pb-free TO-92 packaging	Complies with RoHS Directive 2011/65/EU; eliminates lead contamination risk during reflow soldering and end-of-life recycling.
Low V_CE(sat)	−0.25 V max at I_C = −10 mA ensures minimal voltage drop in saturated switching, improving efficiency in discrete logic inverters and LED drivers.
High f_T / low C_ob ratio	320 MHz f_T with 3–6 pF C_ob enables wideband small-signal amplification without excessive Miller effect degradation.
Stable h_FE across I_C range	Specified h_FE min/max at −2 mA, −10 mA, and −100 mA allows consistent gain prediction in multi-stage amplifiers and current mirrors.
−55°C to +150°C T_J range	Supports operation in automotive under-hood, industrial control, and outdoor embedded systems without derating below −40°C ambient.

Applications

Audio Pre-amplifier Stage	Discrete Logic Level Shifter
Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors before ADC sampling. IC Role / Device Role / Timing Role: PNP small-signal amplifier configured in common-emitter topology with emitter degeneration. Use Value: 2.0 dB noise figure and 320 MHz f_T preserve signal integrity across 20 Hz–20 kHz bandwidth while enabling compact discrete design.	Use Scenario: Converting 3.3 V logic outputs to interface with 5 V or 12 V digital inputs in mixed-voltage systems. IC Role / Device Role / Timing Role: PNP switch operating in saturation/cutoff mode with base resistor network defining switching threshold. Use Value: −0.25 V V_CE(sat) minimizes power loss and heat generation during sustained ON state, supporting >100 kHz toggle rates.
Current Mirror Reference	Linear Voltage Regulator Pass Element
Use Scenario: Providing matched bias current for op-amp input stages or analog front-end calibration circuits. IC Role / Device Role / Timing Role: PNP transistor paired with identical unit in emitter-coupled configuration to replicate reference current. Use Value: Tight h_FE tolerance (220–460 at −2 mA) and low V_BE variation (−0.62 to −0.7 V) ensure <±3% current matching across temperature.	Use Scenario: Acting as series pass element in adjustable linear regulators delivering up to 100 mA output current. IC Role / Device Role / Timing Role: PNP transistor in common-collector configuration with feedback loop controlling base voltage. Use Value: 625 mW power dissipation rating and 200°C/W R_JA allow stable 12 V dropout regulation at 100 mA with minimal heatsink area.

Audio Pre-amplifier Stage

Discrete Logic Level Shifter

Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors before ADC sampling.

IC Role / Device Role / Timing Role: PNP small-signal amplifier configured in common-emitter topology with emitter degeneration.

Use Value: 2.0 dB noise figure and 320 MHz f_T preserve signal integrity across 20 Hz–20 kHz bandwidth while enabling compact discrete design.

Use Scenario: Converting 3.3 V logic outputs to interface with 5 V or 12 V digital inputs in mixed-voltage systems.

IC Role / Device Role / Timing Role: PNP switch operating in saturation/cutoff mode with base resistor network defining switching threshold.

Use Value: −0.25 V V_CE(sat) minimizes power loss and heat generation during sustained ON state, supporting >100 kHz toggle rates.

Current Mirror Reference

Linear Voltage Regulator Pass Element

Use Scenario: Providing matched bias current for op-amp input stages or analog front-end calibration circuits.

IC Role / Device Role / Timing Role: PNP transistor paired with identical unit in emitter-coupled configuration to replicate reference current.

Use Value: Tight h_FE tolerance (220–460 at −2 mA) and low V_BE variation (−0.62 to −0.7 V) ensure <±3% current matching across temperature.

Use Scenario: Acting as series pass element in adjustable linear regulators delivering up to 100 mA output current.

IC Role / Device Role / Timing Role: PNP transistor in common-collector configuration with feedback loop controlling base voltage.

Use Value: 625 mW power dissipation rating and 200°C/W R_JA allow stable 12 V dropout regulation at 100 mA with minimal heatsink area.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC557CRL1G	Higher h_FE range (290–800 at I_C = −2 mA); otherwise identical ratings and pinout.	Better suited for high-gain, low-base-current circuits where tighter h_FE tolerance is critical.	Select BC557CRL1G when gain consistency at microampere base currents is prioritized over cost or availability.
BC857BMTF	SOT-23 surface-mount package; same V_CEO, h_FE, and f_T; lower P_D (310 mW) and R_JA = 300°C/W.	Designed for space-constrained PCBs; requires re-evaluation of thermal layout and trace width for equivalent power handling.	Choose BC857BMTF only when board real estate is limited and thermal management can be enhanced via copper pour or airflow.

Compared with BC557BRL1G, BC557CRL1G offers higher and more tightly binned current gain but no improvement in voltage or frequency capability, while BC857BMTF trades through-hole manufacturability and thermal robustness for miniaturization-neither is pin-compatible without footprint redesign.

Availability

BC557BRL1G is available at Aetrix Electronics and suitable for audio preamplifiers, discrete logic level shifters, and current mirror reference circuits requiring stable component supply, long-term obsolescence management, and RoHS-compliant manufacturing.

Supply support for BC557BRL1G 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, and consumer markets.

The BC557BRL1G belongs to the BC556/557/558 family of general-purpose PNP transistors designed for cost-sensitive, high-reliability linear amplification and switching in non-automotive industrial and consumer electronics.

FAQ

What is the maximum collector-emitter voltage rating for BC557BRL1G?

The BC557BRL1G has a maximum collector-emitter voltage (V_CEO) rating of −45 Vdc under open-base conditions. This value is confirmed in the "Maximum Ratings" table of the official onsemi datasheet (Rev. 3, March 2007) and defines the absolute upper limit for safe operation in common-emitter configurations without breakdown. Exceeding −45 V risks permanent device failure.

Does BC557BRL1G have a Pb-free package?

Yes, BC557BRL1G is explicitly marked as a Pb-free device in the ordering information section of the onsemi datasheet, with "(Pb−Free)" noted alongside its TO-92 package description. It complies with RoHS Directive 2011/65/EU and uses lead-free solder plating on its leads, verified by onsemi's material declaration documentation.

What is the typical current gain (h_FE) of BC557BRL1G at I_C = −2 mA?

The BC557BRL1G exhibits an h_FE range of 220 to 460 when tested at I_C = −2.0 mAdc and V_CE = −5.0 Vdc, per the "ELECTRICAL CHARACTERISTICS" table in the official datasheet. This range reflects the B-series binning and is guaranteed across the full operating temperature range of −55°C to +150°C.

Can BC557BRL1G be used in high-frequency amplifier designs?

Yes, BC557BRL1G supports high-frequency small-signal amplification with a specified current-gain–bandwidth product (f_T) of 320 MHz at I_C = −10 mA and V_CE = −5.0 V. Its 3.0–6.0 pF output capacitance (C_ob) and low noise figure (2.0 dB) make it suitable for audio and sub-VHF applications, though not for RF power stages above 100 MHz.

What is the thermal resistance (R_JA) of BC557BRL1G in free air?

The BC557BRL1G has a thermal resistance from junction-to-ambient (R_JA) of 200°C/W when mounted in still air, as stated in the "THERMAL CHARACTERISTICS" section of the onsemi datasheet. This value assumes standard TO-92 mounting with no heatsink or PCB copper enhancement, and must be derated if ambient temperature exceeds 25°C.

BC557BRL1G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 Long Body, Formed Leads

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: PNP

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

Voltage - Collector Emitter Breakdown (Max):: 45 V

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

Current - Collector Cutoff (Max):: 100nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 180 @ 2mA, 5V

Power - Max:: 625 mW

Frequency - Transition:: 320MHz

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92 (TO-226)

BC557BRL1G FAQ

1.How can I place an order for BC557BRL1G through Aetrix?

Please submit a Request for Quotation (RFQ) for BC557BRL1G 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 BC557BRL1G reliable?

The price and inventory of BC557BRL1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC557BRL1G is usually 5 days.

3.What payment methods are accepted for BC557BRL1G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC557BRL1G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC557BRL1G?

BC557BRL1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC557BRL1G 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 BC557BRL1G?

For technical support, including BC557BRL1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC557BRL1G requirements.

6.How does Aetrix verify that BC557BRL1G is sourced from the original manufacturer or authorized distributors?

All BC557BRL1G 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 BC557BRL1G meets industry standards.

7.What is the process for return or replacement of BC557BRL1G?

All BC557BRL1G units undergo pre-shipment inspection (PSI). If there is an issue with BC557BRL1G, 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 BC557BRL1G part is unused and in its original packaging.

Return procedure for BC557BRL1G:

1.Submit a request within 90 days.

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

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