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

Nexperia USA Inc. BF550,235

Name: BF550,235
Brand: Nexperia USA Inc.
SKU: BF550,235
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BF550,235

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: BF550,235.pdf

Description:: TRANS PNP 40V 0.025A TO-236AB

Quantity:: RFQ Add To RFQ list

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Inventory:16,473

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Product details

Overview

BF550 from Nexperia is a PNP medium-frequency transistor in SOT23 package, rated for −40 V V_CEO, −25 mA I_C, 325 MHz f_T, and 500 K/W R_th(j-a), used in thick/thin-film RF amplification and oscillator stages up to ~100 MHz.

For engineers reviewing the BF550 datasheet, BF550 pinout, BF550 application, or BF550 equivalent, this page delivers verified electrical parameters, thermal behavior, SOT23 terminal mapping, and validated alternatives for medium-frequency analog signal conditioning and biasing circuits.

Technical Context

This PNP bipolar junction transistor operates with low-current (≤25 mA) and low-voltage (≤40 V) constraints, optimized for stable gain at frequencies up to 325 MHz under −1 mA / −10 V bias. Its −50 nA I_CBO and −100 nA I_EBO support low-leakage bias networks in precision analog front-ends.

The device uses silicon planar epitaxial construction with base-emitter voltage of 750 mV at −1 mA/−10 V, and exhibits 0.5 pF C_re for minimal Miller effect in tuned amplifier configurations.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−40 V: Maximum collector-emitter blocking voltage before breakdown in common-emitter configuration.
I_C (DC)	−25 mA: Absolute maximum continuous collector current; design limit for linear operation at ambient ≤25 °C.
f_T	325 MHz: Unity-gain frequency defining usable bandwidth for small-signal amplification.
h_FE	50 min: Minimum DC current gain at −1 mA/−10 V, ensuring predictable bias point stability in fixed-bias designs.
C_re	0.5 pF max: Feedback capacitance limiting high-frequency instability and phase shift in amplifier feedback paths.
R_th(j-a)	500 K/W: Junction-to-ambient thermal resistance on FR4 PCB, dictating derating above 25 °C ambient.

Pinout & Package

SOT23 plastic surface-mounted package (TO-236AB), 3-lead, dimensions per JEDEC MO-178AA: 2.9 × 1.3 × 1.0 mm, 0.95 mm lead pitch, 0.1 mm thickness.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control electrode for forward-active region; requires negative bias relative to emitter for PNP conduction.
2	Emitter	Current source terminal; connected to most positive rail in typical common-emitter amplifier topology.
3	Collector	Output current sink; tied to load resistor or tuned circuit in RF amplifier stages.

Key Features

Feature	Design Value
Medium-frequency optimization	f_T = 325 MHz enables stable gain in 10–100 MHz oscillator and IF amplifier designs.
Low leakage performance	I_CBO ≤ −50 nA ensures minimal temperature drift in bias networks over −65 to +150 °C range.
SOT23 footprint compatibility	Standardized 0.95 mm pitch allows drop-in replacement in existing thin-film and hybrid circuit layouts.
Thermal robustness	150 °C max junction temperature supports operation in sealed industrial enclosures without forced cooling.

Applications

FM Radio IF Amplifier

Crystal Oscillator Buffer

Use Scenario: Amplifying 10.7 MHz intermediate frequency signal in portable FM radio receivers with minimal distortion.

IC Role / Device Role / Timing Role: PNP common-emitter RF amplifier stage providing 15–20 dB small-signal gain at 10.7 MHz.

Use Value: 325 MHz f_T and 0.5 pF C_re maintain flat gain response and low phase noise in narrowband IF filtering.

Use Scenario: Isolating and driving crystal oscillator output to multiple downstream logic inputs without loading.

IC Role / Device Role / Timing Role: Emitter-follower buffer stage delivering low-impedance, rail-referenced clock signal.

Use Value: 50 h_FE min and −4 V V_EBO rating ensure reliable drive into capacitive loads up to 20 pF.

Thin-Film RF Preamp

Temperature-Stable Bias Generator

Use Scenario: First-stage amplification in hybrid microwave modules using thick-film resistors and chip capacitors.

IC Role / Device Role / Timing Role: Medium-frequency preamplifier with fixed emitter degeneration for gain linearity.

Use Value: −25 mA I_C rating and 500 K/W thermal resistance allow stable DC bias under 70 °C board temperature rise.

Use Scenario: Generating precise reference current in analog sensor signal chains operating across automotive temperature ranges.

IC Role / Device Role / Timing Role: Constant-current source using diode-connected PNP configuration with emitter resistor.

Use Value: −50 nA I_CBO and −100 nA I_EBO minimize temperature-induced current drift below 100 ppm/°C.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC856B	Higher h_FE (220–475), same SOT23, −65 V V_CEO, but lower f_T (100 MHz).	Better for DC/low-frequency switching; less suitable for >50 MHz amplification.	Select when higher DC gain and voltage margin outweigh RF bandwidth needs.
MMBT3906	Same V_CEO/I_C, f_T = 250 MHz, h_FE = 100 min, wider industry availability.	Compatible in most BF550 linear amplifier roles but with 75 MHz lower f_T.	Prefer for cost-sensitive production where 250 MHz bandwidth suffices and supply chain resilience is critical.

Compared with BC856B and MMBT3906, the BF550 offers superior high-frequency gain-bandwidth product (325 MHz) at the expense of lower DC current gain and narrower voltage margin-making it optimal for compact, medium-frequency analog signal paths where bandwidth is prioritized over switching speed or voltage headroom.

Availability

BF550 is available at Aetrix Electronics and suitable for FM radio IF amplifiers, crystal oscillator buffers, thin-film RF preamps, and temperature-stable bias generators requiring stable component supply across industrial and consumer electronics programs.

Supply support for BF550 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

Nexperia is a global leader in discrete, logic, and PowerMOS semiconductors, spun off from NXP in 2017 and focused on automotive, industrial, computing, and consumer markets.

The BF550 belongs to Nexperia's legacy PNP RF transistor portfolio, designed specifically for medium-frequency analog signal conditioning in space-constrained hybrid and thin-film circuits.

FAQ

What is the maximum operating frequency for linear amplification with BF550?

The BF550 achieves usable small-signal gain up to approximately 100 MHz in practical amplifier designs, supported by its 325 MHz transition frequency (f_T) and 0.5 pF feedback capacitance. Gain rolls off predictably beyond 100 MHz due to parasitic capacitances and package limitations, making it best suited for IF stages and oscillator buffers rather than UHF applications.

Can BF550 be used in common-base configuration?

Yes, the BF550 supports common-base operation with verified V_CB = −40 V and f_T = 325 MHz, enabling wideband current-buffer applications. Its low C_re (0.5 pF) minimizes Miller multiplication, and the −50 nA I_CBO ensures stable input impedance at high frequencies-ideal for RF current mirrors and broadband amplifiers.

Is BF550 RoHS compliant and halogen-free?

Yes, BF550 meets RoHS Directive 2011/65/EU and is halogen-free per Nexperia standard specifications. The SOT23 package uses lead-free matte tin plating, and the device complies with JEDEC J-STD-020 moisture sensitivity level 1 (MSL1), supporting standard reflow profiles without preconditioning.

How does thermal resistance affect BF550's power handling at 70 °C ambient?

With R_th(j-a) = 500 K/W and P_tot = 250 mW at 25 °C, the BF550's allowable power dissipation drops to ~138 mW at 70 °C ambient (ΔT = 45 K). This requires design-level derating-e.g., limiting I_C to ~18 mA at V_CE = −10 V-to maintain T_j ≤ 150 °C and ensure long-term reliability.

BF550,235 Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Active

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 25 mA

Voltage - Collector Emitter Breakdown (Max):: 40 V

Vce Saturation (Max) @ Ib, Ic:: -

Current - Collector Cutoff (Max):: 50nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 50 @ 1mA, 10V

Power - Max:: 250 mW

Frequency - Transition:: 325MHz

Operating Temperature:: 150°C (TJ)

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: TO-236AB

BF550,235 FAQ

1.How can I place an order for BF550,235 through Aetrix?

Please submit a Request for Quotation (RFQ) for BF550,235 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 BF550,235 reliable?

The price and inventory of BF550,235 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BF550,235 is usually 5 days.

3.What payment methods are accepted for BF550,235?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BF550,235 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BF550,235?

BF550,235 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BF550,235 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 BF550,235?

For technical support, including BF550,235 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BF550,235 requirements.

6.How does Aetrix verify that BF550,235 is sourced from the original manufacturer or authorized distributors?

All BF550,235 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 BF550,235 meets industry standards.

7.What is the process for return or replacement of BF550,235?

All BF550,235 units undergo pre-shipment inspection (PSI). If there is an issue with BF550,235, 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 BF550,235 part is unused and in its original packaging.

Return procedure for BF550,235:

1.Submit a request within 90 days.

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

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