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

Diodes Incorporated BC857CT-7-F

Name: BC857CT-7-F
Brand: Diodes Incorporated
SKU: BC857CT-7-F
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC857CT-7-F

Manufacturer:: Diodes Incorporated

Category:: Single Bipolar Transistors

Package:: SOT-523

Datasheet:: BC857CT-7-F.pdf

Description:: TRANS PNP 45V 0.1A SOT-523

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC857CT-7-F from Diodes Incorporated is a PNP small-signal transistor in SOT523 package, rated for -45 V V_CEO, -100 mA I_C, and 150 mW power dissipation, with h_FE = 250–475 at I_C = -2 mA, used in low-power switching and amplification circuits in automotive body control modules and portable sensor interfaces.

For engineers reviewing the BC857CT-7-F datasheet, BC857CT-7-F pinout, BC857CT-7-F application, or BC857CT-7-F equivalent, key selection criteria include verified V_CEO rating, h_FE binning (C-grade), thermal resistance (R_θJA = 833 °C/W), AEC-Q101 qualification, and SOT523 footprint compatibility with space-constrained PCB layouts.

Technical Context

This PNP bipolar junction transistor uses epitaxial planar die construction for stable gain and low leakage. It operates with V_EBO = -6 V and exhibits f_T = 100 MHz at V_CE = -5 V and I_C = -10 mA, supporting high-frequency small-signal amplification in bias-stable configurations.

Its complementary NPN counterpart is BC847CT-7-F. The device meets AEC-Q101 stress test requirements for temperature cycling, humidity, and ESD (HBM = 4 kV), confirming suitability for automotive interior electronics where reliability under thermal cycling is critical.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	-45 V - Maximum safe collector-emitter voltage before breakdown in common-emitter configuration
I_C	-100 mA - Continuous DC collector current limit defining switching/amplification headroom
h_FE (C grade)	250–475 - Confirmed DC current gain range at V_CE = -5 V, I_C = -2 mA for predictable bias design
P_D	150 mW - Steady-state power dissipation limit on standard FR-4 PCB with 1 oz copper
f_T	100 MHz - Minimum guaranteed transition frequency enabling audio and low-RF signal amplification
R_θJA	833 °C/W - Junction-to-ambient thermal resistance under defined PCB layout, guiding thermal derating
ESD HBM	4,000 V - Human Body Model robustness level ensuring handling survivability in assembly lines

Pinout & Package

Package: SOT523 - ultra-small surface-mount plastic package (1.60 mm × 1.60 mm × 0.65 mm), weight ≈ 0.002 g, UL 94V-0 rated, matte tin-plated terminals.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal in PNP operation	Connected to higher potential rail; defines reference for base drive and current flow direction
2 (Base)	Control input for minority-carrier injection	Requires negative bias relative to emitter to forward-bias BE junction and enable conduction
3 (Collector)	Output current terminal	Typically tied to load and ground-return path; voltage swing limited by V_CEO = -45 V rating

Key Features

Feature	Design Value
AEC-Q101 qualified	Validated for automotive applications including interior lighting and door module logic
Green compound & lead-free	Halogen- and antimony-free molding compound (<900 ppm Br/Cl, <1000 ppm Sb) meeting RoHS 3
Epitaxial planar die	Enables tight h_FE distribution and low leakage (I_CBO ≤ -15 nA at 25°C)
SOT523 footprint	Reduces board area by >50% vs. SOT23 while maintaining solder joint reliability per J-STD-020 Level 1

Applications

Automotive Interior Lighting Control

Portable Gas Sensor Signal Conditioning

Use Scenario: Driving LED strings in door handle illumination and map light modules with PWM dimming.

IC Role / Device Role / Timing Role: Low-side PNP switch controlling current path to ground via base-driven saturation.

Use Value: V_CE(SAT) ≤ -650 mV at I_C = -100 mA ensures <65 mW conduction loss, minimizing thermal rise in sealed assemblies.

Use Scenario: Amplifying weak transducer output (e.g., MQ-2 analog signal) in battery-powered air quality monitors.

IC Role / Device Role / Timing Role: Common-emitter small-signal amplifier with fixed bias network.

Use Value: f_T = 100 MHz and NF = 10 dB at 1 MHz support clean 20–200 Hz gas response without added noise floor degradation.

Industrial Pushbutton Interface Logic

Medical Wearable Battery Monitoring

Use Scenario: Debouncing and level-shifting mechanical switch inputs in DIN-rail PLC I/O modules.

IC Role / Device Role / Timing Role: Digital inverter stage converting 0–3.3 V logic to 5 V/12 V open-collector outputs.

Use Value: h_FE ≥ 250 ensures full saturation with ≤10 µA base drive, reducing MCU GPIO loading and enabling multi-channel integration.

Use Scenario: Discrete charge/discharge path control in compact Li-ion battery fuel gauging circuits.

IC Role / Device Role / Timing Role: Precision current mirror component in coulomb counting front-end.

Use Value: Tight I_CBO ≤ -4 nA at +150°C prevents thermal drift errors during extended wearable operation at skin temperature.

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
BC857BW-7-F	SOT323 package (larger footprint), same electrical specs, non-AEC-Q101	Preferred for non-automotive industrial prototypes requiring easier rework	Select when board space allows larger pad layout and AEC-Q101 is not required
MMBT3906LT1G	h_FE = 100–300 (lower gain spread), SOT23, AEC-Q101 qualified	Better suited for general-purpose logic inversion where tighter gain control is unnecessary	Choose when cost sensitivity outweighs need for C-grade h_FE consistency

Compared with BC857BW-7-F and MMBT3906LT1G, BC857CT-7-F uniquely combines AEC-Q101 compliance, SOT523 miniaturization, and C-bin h_FE (250–475), making it optimal for space-constrained automotive signal conditioning where gain predictability and qualification are jointly required.

Availability

BC857CT-7-F is available at Aetrix Electronics and suitable for automotive interior electronics, portable sensor interfaces, and industrial pushbutton logic requiring stable component supply across production lifecycles.

Supply support for BC857CT-7-F 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and the U.S.

The BC857 series belongs to Diodes' AEC-Q101-qualified small-signal transistor product line, engineered specifically for reliable low-power switching and amplification in harsh-environment automotive and industrial control systems.

FAQ

What is the maximum operating temperature for BC857CT-7-F?

The BC857CT-7-F has an operating junction temperature range of -55°C to +150°C, validated per AEC-Q101 thermal cycling and storage tests. Its R_θJA = 833 °C/W requires derating above +70°C ambient to maintain safe T_J; at +125°C ambient, max usable power drops to ~30 mW on standard PCB layout.

Is BC857CT-7-F pin-compatible with BC847CT-7-F?

No - BC857CT-7-F (PNP) and BC847CT-7-F (NPN) share identical SOT523 pinout (Emitter-Base-Collector), but polarity reversal means direct substitution requires circuit topology changes. Both use same marking orientation and pad layout, enabling shared PCB footprint for complementary designs.

Does BC857CT-7-F require external base resistors in switching applications?

Yes - base current must be limited to avoid exceeding I_B = -5 mA absolute maximum. For I_C = -100 mA saturation, typical design uses 1–10 kΩ resistor between MCU GPIO and base, sized using h_FE(min) = 250 and V_BE(SAT) ≈ -700 mV to ensure forced β ≥ 10.

How does the C-grade h_FE bin differ from A and B grades?

The C-grade (BC857CT-7-F) specifies h_FE = 250–475 at I_C = -2 mA, versus A-grade (125–220) and B-grade (290–520). This wider mid-to-high range improves bias stability across temperature in amplifier designs while avoiding excessive gain that could cause oscillation in marginal layouts.

BC857CT-7-F Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: SOT-523

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:: 650mV @ 5mA, 100mA

Current - Collector Cutoff (Max):: 15nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 420 @ 2mA, 5V

Power - Max:: 150 mW

Frequency - Transition:: 100MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-523

BC857CT-7-F FAQ

1.How can I place an order for BC857CT-7-F through Aetrix?

Please submit a Request for Quotation (RFQ) for BC857CT-7-F 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 BC857CT-7-F reliable?

The price and inventory of BC857CT-7-F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC857CT-7-F is usually 5 days.

3.What payment methods are accepted for BC857CT-7-F?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC857CT-7-F transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC857CT-7-F?

BC857CT-7-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC857CT-7-F 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 BC857CT-7-F?

For technical support, including BC857CT-7-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC857CT-7-F requirements.

6.How does Aetrix verify that BC857CT-7-F is sourced from the original manufacturer or authorized distributors?

All BC857CT-7-F 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 BC857CT-7-F meets industry standards.

7.What is the process for return or replacement of BC857CT-7-F?

All BC857CT-7-F units undergo pre-shipment inspection (PSI). If there is an issue with BC857CT-7-F, 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 BC857CT-7-F part is unused and in its original packaging.

Return procedure for BC857CT-7-F:

1.Submit a request within 90 days.

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

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