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

Nexperia USA Inc. BCX71K,235

Name: BCX71K,235
Brand: Nexperia USA Inc.
SKU: BCX71K,235
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BCX71K,235

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

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

Datasheet:: BCX71K,235.pdf

Description:: TRANS PNP 45V 0.1A TO-236AB

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BCX71K,235 from Nexperia is a PNP general-purpose bipolar junction transistor in SOT23 package, rated for −45 V V_CEO, −100 mA I_C, and featuring h_FE = 380–630 at I_C = −2 mA, used in low-noise, low-frequency amplification and switching within hybrid analog circuits.

For engineers reviewing the BCX71K,235 datasheet, BCX71K,235 pinout, BCX71K,235 application, or BCX71K,235 equivalent, key selection factors include its verified PNP polarity, SOT23 thermal resistance (500 K/W), low-noise figure (2–6 dB), collector capacitance (4.5 pF), and guaranteed h_FE minimum of 380 at −2 mA.

Technical Context

This device operates as a silicon PNP BJT with base-emitter and base-collector junctions optimized for stable DC gain and low noise in small-signal linear and switching roles. Its design supports operation up to 150 °C junction temperature and maintains h_FE consistency across I_C = −10 μA to −50 mA ranges.

It exhibits V_CEsat ≤ −250 mV at I_C = −10 mA/I_B = −0.25 mA and V_BE ≈ −650 mV at I_C = −2 mA/V_CE = −5 V, confirming suitability for bias-stable amplifier stages and low-power switch drivers where predictable turn-on voltage and saturation behavior are required.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−45 V - maximum safe collector-emitter voltage under open-base condition
I_C (DC)	−100 mA - continuous collector current rating defining linear/saturation operating envelope
h_FE (min)	380 at I_C = −2 mA - ensures reliable current amplification in low-level signal paths
f_T	100 MHz - usable bandwidth limit for small-signal amplification up to VHF range
F (noise figure)	2–6 dB at I_C = −200 μA - quantifies added noise in audio/low-level sensor front-ends
R_th(j-a)	500 K/W - thermal resistance on FR4 PCB, guiding heatsinking and power derating
C_c	4.5 pF - collector junction capacitance affecting high-frequency gain roll-off

Pinout & Package

BCX71K,235 is housed in a plastic surface-mount SOT23 (TO-236AB) package measuring 2.9 × 1.3 × 1.0 mm, with gull-wing leads and standard JEDEC footprint compatibility.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control terminal; requires −0.65 V typical forward bias to activate conduction
2	Emitter	Current source terminal; connected to higher potential in PNP configuration
3	Collector	Current sink terminal; carries load current toward ground or lower-potential rail

Key Features

Feature	Design Value
Low-noise operation	2–6 dB noise figure enables use in microphone preamps and sensor signal conditioning
High DC current gain	h_FE ≥ 380 at −2 mA supports single-stage amplification without cascading
Stable gain over current range	h_FE remains ≥ 110 even at −50 mA, ensuring consistent switching thresholds
SOT23 footprint compatibility	Standard JEDEC TO-236AB outline allows drop-in replacement in space-constrained PCB layouts

Applications

Audio Pre-amplifier Stage

Low-Power Switch Driver

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

IC Role / Device Role / Timing Role: PNP small-signal amplifier providing voltage gain with minimal added noise.

Use Value: 2–6 dB noise figure and h_FE ≥ 380 ensure high SNR and stable bias point across temperature.

Use Scenario: Driving LED indicators or small relays from microcontroller GPIO pins.

IC Role / Device Role / Timing Role: Low-voltage PNP switch controlling current flow to grounded loads.

Use Value: V_CEsat ≤ −250 mV at −10 mA reduces power loss and heat generation in battery-powered systems.

Hybrid Analog Filter Node

Current Mirror Reference

Use Scenario: Implementing active RC filter sections in mixed-signal instrumentation modules.

IC Role / Device Role / Timing Role: Transconductance element in OTA-like configurations with fixed bias.

Use Value: Low C_c (4.5 pF) and f_T = 100 MHz preserve phase linearity up to 10 kHz passband.

Use Scenario: Building matched current sources in precision analog front-ends or sensor bias networks.

IC Role / Device Role / Timing Role: PNP leg of a two-transistor current mirror with BCX70-series NPN counterpart.

Use Value: Guaranteed h_FE spread and complementary marking (BK* vs BJ*) support tight current ratio matching.

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
BC857BK,215	Same SOT23 package, identical h_FE bin (380–630), but updated Nexperia part number with revised traceability	No functional difference; fully interchangeable in legacy and new designs	Select when sourcing newer production lots with full Nexperia lifecycle support
MMBT3906LT1G	Lower h_FE (100–300), higher V_CEsat (−400 mV typ.), same −40 V rating and SOT23 footprint	Less suitable for low-noise gain stages; acceptable for basic switching where gain margin is ample	Choose only if BCX71K,235 is unavailable and circuit tolerates reduced gain and higher saturation voltage

Compared with BCX71K,235, BC857BK,215 offers identical electrical performance and direct continuity, while MMBT3906LT1G trades gain and noise performance for broader global availability-making the former ideal for design continuity and the latter a fallback for cost-sensitive, non-critical switching.

Availability

BCX71K,235 is available at Aetrix Electronics and suitable for audio pre-amplifiers, low-power switch drivers, hybrid analog filter nodes, and current mirror references requiring stable component supply across industrial and consumer electronics programs.

Supply support for BCX71K,235 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, formed in 2017 from the former NXP Standard Products division.

The BCX71 series belongs to Nexperia's general-purpose bipolar transistor product line, engineered for reliability and consistency in low-noise, low-frequency analog and switching applications across automotive, industrial, and consumer markets.

FAQ

Is BCX71K,235 RoHS compliant and lead-free?

Yes, BCX71K,235 is RoHS compliant and manufactured with lead-free terminations per Nexperia's standard process. The SOT23 package uses matte tin plating, and full compliance documentation-including test reports and declarations-is available through Aetrix Electronics' component traceability portal upon request.

What is the maximum allowable power dissipation at 70 °C ambient?

At T_amb = 70 °C, the maximum allowable power dissipation is 150 mW. This is derived from the 250 mW rating at 25 °C and R_th(j-a) = 500 K/W, applying linear derating: P_tot = 250 mW − (70 − 25) × (250 mW / 125) = 150 mW, consistent with Nexperia's published thermal curve.

Can BCX71K,235 be used as a direct replacement for BCX71J in existing designs?

Yes, BCX71K,235 can replace BCX71J in most cases, as both share identical package, voltage/current ratings, and pinout. However, BCX71K offers higher h_FE (380–630 vs. 250–460), which may increase gain or alter bias points-verify stability in high-gain amplifier stages before substitution.

Does BCX71K,235 have qualified AEC-Q101 stress test data for automotive use?

No, BCX71K,235 is not AEC-Q101 qualified. It is specified for industrial and consumer applications per its data sheet. For automotive-grade equivalents, consider Nexperia's BC857BKW series, which carries full AEC-Q101 qualification and identical electrical specs in the same SOT23 package.

BCX71K,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):: 100 mA

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

Vce Saturation (Max) @ Ib, Ic:: 550mV @ 1.25mA, 50mA

Current - Collector Cutoff (Max):: 20nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 380 @ 2mA, 5V

Power - Max:: 250 mW

Frequency - Transition:: 100MHz

Operating Temperature:: 150°C (TJ)

Grade:: Automotive

Qualification:: AEC-Q100

Mounting Type:: Surface Mount

Supplier Device Package:: TO-236AB

BCX71K,235 FAQ

1.How can I place an order for BCX71K,235 through Aetrix?

Please submit a Request for Quotation (RFQ) for BCX71K,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 BCX71K,235 reliable?

The price and inventory of BCX71K,235 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BCX71K,235 is usually 5 days.

3.What payment methods are accepted for BCX71K,235?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BCX71K,235 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BCX71K,235?

BCX71K,235 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BCX71K,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 BCX71K,235?

For technical support, including BCX71K,235 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BCX71K,235 requirements.

6.How does Aetrix verify that BCX71K,235 is sourced from the original manufacturer or authorized distributors?

All BCX71K,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 BCX71K,235 meets industry standards.

7.What is the process for return or replacement of BCX71K,235?

All BCX71K,235 units undergo pre-shipment inspection (PSI). If there is an issue with BCX71K,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 BCX71K,235 part is unused and in its original packaging.

Return procedure for BCX71K,235:

1.Submit a request within 90 days.

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

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