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

onsemi BCX70JLT1

Name: BCX70JLT1
Brand: onsemi
SKU: BCX70JLT1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BCX70JLT1

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: BCX70JLT1.pdf

Description:: TRANS NPN 45V 0.2A SOT23-3

Quantity:: RFQ Add To RFQ list

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Inventory:28,800

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Product details

Overview

BCX70JLT1 from ON Semiconductor (formerly Motorola) is an NPN silicon small-signal transistor in SOT-23 package, rated for 45 V_CEO, 200 mA I_C, and 225 mW P_D on FR-5 board. It delivers h_FE = 100–250 at I_C = 10 mA, V_CE = 5 V, and f_T = 125 MHz - suitable for general-purpose amplification and switching in portable audio preamps and low-power sensor interface circuits.

For engineers reviewing the BCX70JLT1 datasheet, pinout, applications, or equivalent options, this page provides verified electrical specs, thermal derating data, SOT-23 terminal mapping, noise performance (NF ≤ 6.0 dB), and two validated alternative parts with documented h_FE and V_CE(sat) differences.

Technical Context

This device operates as a discrete bipolar junction transistor with fixed emitter-base and collector-base junctions optimized for linear amplification and saturated switching. Its DC current gain spans three variants (G/J/K), with BCX70JLT1 specifically specified for h_FE = 100–250 at I_C = 10 mA and h_FE = 90–220 at I_C = 2 mA - enabling predictable biasing in Class-A amplifier stages and digital logic-level translators.

Thermal behavior is defined by R_θJA = 556°C/W on FR-5 board and 417°C/W on alumina substrate, with derating slopes of 1.8 mW/°C and 2.4 mW/°C respectively. Switching is characterized by t_on ≤ 150 ns and t_off ≤ 800 ns under defined test conditions (I_B1 = I_B2 = 1.0 mA, R_L = 990 Ω).

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum collector-emitter voltage before breakdown; sets rail limit for 3.3 V/5 V logic-level switch drivers.
I_C (continuous)	200 mA - Continuous collector current rating; supports medium-gain preamp stages driving 10 kΩ loads.
h_FE @ 10 mA	100–250 - DC current gain range at I_C = 10 mA, V_CE = 5 V; enables stable bias design with ±25% tolerance margin.
V_CE(sat)	≤ 0.55 V @ I_C = 50 mA, I_B = 1.25 mA - Low saturation voltage ensures < 27.5 mW power loss in switching mode.
f_T	125 MHz - Current-gain bandwidth product; supports RF amplification up to ~20 MHz with usable gain.
NF	≤ 6.0 dB @ I_C = 0.2 mA, R_S = 2 kΩ - Noise figure suitable for microphone preamplifier input stages.
R_θJA	556°C/W on FR-5 - Thermal resistance determines junction temperature rise; requires layout-aware copper pour for >100 mW dissipation.

Pinout & Package

SOT-23 (TO-236AB) plastic surface-mount package with 3-pin configuration, 0.95 mm lead pitch, and JEDEC-standard footprint. Designed for automated pick-and-place assembly using 8 mm embossed tape (T1 suffix = 3000 units/reel).

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current sink node; connects to ground or low-impedance return path in common-emitter configurations.
2	Base	Control input; requires current-limited drive (e.g., 10 kΩ resistor from 3.3 V) to achieve target I_C.
3	Collector	Current source node; ties to V_CC via load resistor or directly to switched rail in low-side driver topologies.

Key Features

Feature	Design Value
High h_FE consistency	100–250 range at 10 mA ensures predictable DC bias without trim resistors in production designs.
Low V_CE(sat)	≤ 0.55 V minimizes conduction loss in battery-powered switching applications like LED blinkers.
125 MHz f_T	Enables stable small-signal amplification up to 20 MHz with ≥10 dB gain margin.
6.0 dB noise figure	Validated at 1 kHz with 2 kΩ source impedance - meets SNR requirements for analog sensor front-ends.
JEDEC SOT-23 footprint	Standardized 3-pin layout ensures compatibility with existing reflow profiles and stencil apertures.

Applications

Audio Preamp Stage	Logic-Level Translator
Use Scenario: Amplifying electret microphone output (10 mV RMS) to line-level (1 V RMS) in portable voice recorders. IC Role / Device Role / Timing Role: NPN common-emitter amplifier with fixed emitter degeneration for gain stability and distortion control. Use Value: h_FE = 100–250 and NF ≤ 6.0 dB ensure ≥40 dB voltage gain with < 1% THD at 1 kHz.	Use Scenario: Converting 1.8 V GPIO signals to 5 V TTL levels for legacy peripheral interfacing. IC Role / Device Role / Timing Role: Saturated switch operating in cutoff/saturation regions with controlled base drive. Use Value: V_CE(sat) ≤ 0.55 V guarantees output high-state margin > 4.4 V when driving 10 kΩ loads.
Sensor Signal Conditioning	Low-Power Oscillator Core
Use Scenario: Buffering thermistor bridge outputs in wearable health monitors with 3 V coin-cell supply. IC Role / Device Role / Timing Role: Emitter-follower buffer isolating high-impedance sensor from ADC input. Use Value: I_C = 200 mA rating allows 100 µA bias current with >10× safety margin for 10-year field life.	Use Scenario: Building Colpitts oscillator for 10–30 MHz clock generation in low-cost RF modules. IC Role / Device Role / Timing Role: Active device sustaining oscillation via tuned LC tank and capacitive feedback. Use Value: f_T = 125 MHz provides sufficient gain-bandwidth margin for reliable startup and frequency stability.

Audio Preamp Stage

Logic-Level Translator

Use Scenario: Amplifying electret microphone output (10 mV RMS) to line-level (1 V RMS) in portable voice recorders.

IC Role / Device Role / Timing Role: NPN common-emitter amplifier with fixed emitter degeneration for gain stability and distortion control.

Use Value: h_FE = 100–250 and NF ≤ 6.0 dB ensure ≥40 dB voltage gain with < 1% THD at 1 kHz.

Use Scenario: Converting 1.8 V GPIO signals to 5 V TTL levels for legacy peripheral interfacing.

IC Role / Device Role / Timing Role: Saturated switch operating in cutoff/saturation regions with controlled base drive.

Use Value: V_CE(sat) ≤ 0.55 V guarantees output high-state margin > 4.4 V when driving 10 kΩ loads.

Sensor Signal Conditioning

Low-Power Oscillator Core

Use Scenario: Buffering thermistor bridge outputs in wearable health monitors with 3 V coin-cell supply.

IC Role / Device Role / Timing Role: Emitter-follower buffer isolating high-impedance sensor from ADC input.

Use Value: I_C = 200 mA rating allows 100 µA bias current with >10× safety margin for 10-year field life.

Use Scenario: Building Colpitts oscillator for 10–30 MHz clock generation in low-cost RF modules.

IC Role / Device Role / Timing Role: Active device sustaining oscillation via tuned LC tank and capacitive feedback.

Use Value: f_T = 125 MHz provides sufficient gain-bandwidth margin for reliable startup and frequency stability.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC847BJT1G	h_FE = 200–450 @ 10 mA (wider spread); V_CE(sat) = 0.25 V @ 10 mA (lower)	Better for ultra-low-loss switching; less predictable DC bias due to wider h_FE distribution	Select when minimizing conduction loss is critical and gain tolerance can be managed via feedback.
MMBT3904LT1G	h_FE = 100–300 @ 10 mA (similar range); V_CE(sat) = 0.2 V @ 10 mA (lower); f_T = 300 MHz (higher)	Superior RF performance and lower saturation loss, but higher cost and tighter layout constraints	Choose for high-frequency amplification (>50 MHz) or where 0.2 V V_CE(sat) improves efficiency in battery systems.

Compared with BCX70JLT1, BC847BJT1G offers lower V_CE(sat) but looser h_FE control, while MMBT3904LT1G provides higher f_T and lower saturation voltage at the expense of cost and thermal derating margin (R_θJA = 625°C/W).

Availability

BCX70JLT1 is available at Aetrix Electronics and suitable for portable audio preamps, logic-level translators, sensor signal conditioning, and low-power oscillator circuits requiring stable component supply across industrial and consumer production runs.

Supply support for BCX70JLT1 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

ON Semiconductor is a global semiconductor supplier delivering energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, medical, and IoT applications.

The BCX70JLT1 belongs to ON Semiconductor's legacy small-signal transistor portfolio, designed for cost-sensitive, high-volume applications demanding consistent h_FE, low noise, and robust SOT-23 reliability in space-constrained PCB layouts.

FAQ

What is the maximum continuous collector current for BCX70JLT1?

The BCX70JLT1 has a maximum continuous collector current (I_C) of 200 mA at T_A = 25°C on FR-5 board. Derating applies above 25°C at 1.8 mW/°C, reducing usable current as ambient temperature rises - e.g., at 75°C ambient, maximum I_C drops to ~160 mA assuming V_CE = 5 V and h_FE = 150.

Does BCX70JLT1 support switching applications?

Yes, BCX70JLT1 supports switching applications with verified t_on ≤ 150 ns and t_off ≤ 800 ns under standard test conditions (I_B1 = I_B2 = 1.0 mA, R_L = 990 Ω). Its V_CE(sat) ≤ 0.55 V at I_C = 50 mA ensures low conduction loss in digital output stages and LED drivers.

What is the h_FE range for BCX70JLT1 at 2 mA collector current?

At I_C = 2.0 mA and V_CE = 5.0 V, the BCX70JLT1 exhibits h_FE = 120–380 per Motorola datasheet Figure 8. This wide range reflects process variation within the J-grade bin and must be accommodated in bias network design - e.g., using emitter degeneration resistors to stabilize Q-point.

Can BCX70JLT1 be used in RF amplifier designs?

Yes, BCX70JLT1 is suitable for RF amplifier designs up to ~20 MHz due to its f_T = 125 MHz and C_obo = 4.5 pF. Its noise figure ≤ 6.0 dB at 1 kHz makes it appropriate for IF amplifiers and low-frequency RF front-ends, though not recommended for >50 MHz VHF/UHF stages where MMBT3904LT1G's 300 MHz f_T is preferred.

What is the thermal resistance of BCX70JLT1 on FR-5 board?

The BCX70JLT1 has a thermal resistance R_θJA of 556°C/W on FR-5 board (1.0 × 0.75 × 0.062 in.) at T_A = 25°C. This value assumes minimal copper pour; adding 100 mm² of 2 oz copper on the collector pad reduces R_θJA by ~15%, improving power handling capability in BCX70JLT1-based designs.

BCX70JLT1 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Bulk

Product Status:: Active

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 200 mA

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

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

Current - Collector Cutoff (Max):: 20nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 250 @ 2mA, 5V

Power - Max:: 300 mW

Frequency - Transition:: 125MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3 (TO-236)

BCX70JLT1 FAQ

1.How can I place an order for BCX70JLT1 through Aetrix?

Please submit a Request for Quotation (RFQ) for BCX70JLT1 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 BCX70JLT1 reliable?

The price and inventory of BCX70JLT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BCX70JLT1 is usually 5 days.

3.What payment methods are accepted for BCX70JLT1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BCX70JLT1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BCX70JLT1?

BCX70JLT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BCX70JLT1 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 BCX70JLT1?

For technical support, including BCX70JLT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BCX70JLT1 requirements.

6.How does Aetrix verify that BCX70JLT1 is sourced from the original manufacturer or authorized distributors?

All BCX70JLT1 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 BCX70JLT1 meets industry standards.

7.What is the process for return or replacement of BCX70JLT1?

All BCX70JLT1 units undergo pre-shipment inspection (PSI). If there is an issue with BCX70JLT1, 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 BCX70JLT1 part is unused and in its original packaging.

Return procedure for BCX70JLT1:

1.Submit a request within 90 days.

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

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