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Diodes Incorporated BC857B-7-F
- Part No.:
- BC857B-7-F
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
BC857B-7-F.pdf
- Description:
- TRANS PNP 45V 0.1A SOT-23-3
- Quantity:
- Payment:
- Shipping:
Inventory:87,540
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Product details
Overview
BC857B-7-F from Diodes Incorporated is a PNP small-signal transistor in SOT23 package, rated for VCEO = −45 V, IC = −100 mA, and hFE = 220–475 at IC = −2 mA. It delivers VCE(sat) ≤ −300 mV at IC = −10 mA / IB = −0.5 mA and operates from −55°C to +150°C. It is used in low-power switching and audio-frequency amplification stages in industrial control interfaces.
For engineers reviewing the BC857B-7-F datasheet, BC857B-7-F pinout, BC857B-7-F application, or BC857B-7-F equivalent, this page provides verified electrical parameters, thermal derating curves, JEDEC-qualified reliability data, SOT23 mechanical dimensions, and direct comparison with BC857A and BC857C variants.
Technical Context
This PNP bipolar junction transistor operates in active, saturation, and cutoff regions with DC current gain (hFE) tightly binned across BC857A/B/C grades. Its −45 V VCEO rating supports use in 24 V rail logic-level switching, while fT ≥ 100 MHz enables stable AF amplification up to 20 kHz with <10 dB noise figure.
Thermal design is enabled by RθJA = 357 °C/W on 15 mm × 15 mm 1 oz copper PCB, and ESD robustness includes 4 kV HBM per JEDEC Class 3A. The device meets AEC-Q200 stress test requirements for high-reliability industrial environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | −45 V - Maximum collector-emitter voltage before breakdown; sets safe operating range for 24 V system switching |
| IC (continuous) | −100 mA - Continuous collector current limit; defines max load drive capability in linear or saturated mode |
| hFE @ IC = −2 mA | 220–475 - DC current gain binning range; ensures predictable base drive sizing for consistent switching thresholds |
| VCE(sat) @ IC/IB | ≤ −300 mV @ −10 mA / −0.5 mA - Low saturation voltage reduces power loss and self-heating in digital logic interface circuits |
| fT | ≥ 100 MHz - Gain-bandwidth product; supports stable small-signal amplification up to audio frequencies with minimal phase shift |
| NF | 2–10 dB @ 1 kHz - Noise figure at 200 Hz bandwidth; suitable for low-noise preamplifier stages in sensor signal conditioning |
| RθJA | 357 °C/W - Junction-to-ambient thermal resistance on 15 mm × 15 mm copper; enables accurate power dissipation margining |
Pinout & Package
Package: SOT23 - surface-mount plastic package with matte tin-plated leads, UL 94V-0 rated, 0.008 g weight, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| E (Emitter) | Current source terminal | Connected to higher potential rail in PNP switch; determines polarity of bias network and current flow direction |
| B (Base) | Control input | Receives negative-going logic or analog drive; requires current-limiting resistor sized using hFE min for reliable saturation |
| C (Collector) | Current sink terminal | Drives load to ground or lower-potential node; voltage swing limited by VCEO and safe operating area boundaries |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-qualified reliability | Qualified per AEC-Q200 standards for automotive-grade stress testing; validated for industrial temperature cycling and humidity exposure |
| Green compound packaging | Halogen- and antimony-free molding compound (<900 ppm Br/Cl, <1000 ppm Sb); compliant with RoHS 3 and environmental directives |
| Low VCE(sat) at medium current | −300 mV max at −10 mA collector current; minimizes conduction loss in battery-powered load switches and level translators |
| High hFE consistency | 220–475 range at −2 mA; enables tighter base resistor tolerance and reduced layout sensitivity in discrete amplifier designs |
| ESD robustness | 4 kV HBM per JEDEC Class 3A; eliminates need for external protection diodes in board-level ESD-prone interfaces |
Applications
| Industrial Sensor Interface | 24 V PLC Input Stage |
|---|---|
|
Use Scenario: Amplifying low-level thermistor or RTD bridge outputs in programmable logic controller analog input modules. IC Role / Device Role / Timing Role: PNP emitter-follower buffer providing high input impedance and rail-to-rail output swing referenced to 24 V supply. Use Value: VBE(on) = −600 to −750 mV ensures stable bias point across temperature; hFE ≥ 220 guarantees minimal base current loading on precision resistive networks. |
Use Scenario: Converting 24 V sinking field signals into 3.3 V logic-compatible levels for microcontroller GPIO inputs. IC Role / Device Role / Timing Role: Active-low level shifter with grounded emitter, collector driving pull-up to 3.3 V, base driven via current-limiting resistor from 24 V input. Use Value: VCE(sat) ≤ −300 mV ensures output stays below 0.3 V under full load, meeting TTL/CMOS low-level threshold requirements reliably. |
| Audio Preamp Stage | Power Supply Enable Switch |
|
Use Scenario: First-stage amplification of microphone signals in portable industrial voice recorders operating from single 3.7 V Li-ion cells. IC Role / Device Role / Timing Role: Common-emitter amplifier biased for Class-A operation with emitter degeneration resistor for linearity. Use Value: fT ≥ 100 MHz and NF ≤ 10 dB enable clean amplification up to 20 kHz with SNR > 65 dB; low RθJA prevents thermal drift during extended recording. |
Use Scenario: Enabling/disabling auxiliary 5 V LDO rails in multi-rail embedded systems based on microcontroller GPIO commands. IC Role / Device Role / Timing Role: High-side switch controlling LDO EN pin; emitter tied to 5 V, collector to EN, base driven low to activate. Use Value: −45 V VCEO provides 2× margin over 5 V rail; −100 mA IC exceeds typical EN pin leakage, ensuring fast, glitch-free turn-on/turn-off. |
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 |
|---|---|---|---|
| BC857A-7-F | hFE = 125–250 (lower gain bin), same VCEO/IC/package | Suitable where base drive current is abundant and gain stability at low IC is less critical | Select when designing for cost-sensitive volume production with relaxed hFE tolerance requirements |
| BC857C-7-F | hFE = 420–800 (higher gain bin), identical absolute ratings and thermal specs | Preferred in ultra-low-base-current designs such as battery-operated sensor nodes with weak drive sources | Choose when minimizing base resistor value or reducing MCU GPIO loading is essential for power budget or timing constraints |
Compared with BC857A-7-F and BC857C-7-F, BC857B-7-F offers balanced hFE performance-sufficient for robust saturation without excessive gain-induced instability-making it optimal for general-purpose industrial switching and amplification where design margin and manufacturability are prioritized.
Availability
BC857B-7-F is available at Aetrix Electronics and suitable for industrial sensor interfaces, 24 V PLC input conditioning, and audio preamplifier stages requiring stable component supply, long-term lifecycle support, and JEDEC-qualified reliability.
Supply support for BC857B-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, specializing in high-reliability components for industrial, automotive, and computing markets.
BC857B-7-F belongs to the BC856–BC858 family of PNP transistors designed specifically for automatic insertion, switching, and AF amplification in space-constrained, thermally demanding applications.
FAQ
What is the maximum continuous collector current for BC857B-7-F?
The maximum continuous collector current is −100 mA at TA = +25°C. Derating applies above 25°C per the 357 °C/W RθJA curve; at 85°C ambient, max IC drops to approximately −65 mA to maintain junction temperature ≤ +150°C.
Is BC857B-7-F suitable for automotive applications?
Yes-BC857B-7-F is qualified to AEC-Q200 stress test standards for high-reliability operation. While the standard part is not automotive-grade, its qualification basis matches that of the automotive-compliant BC857BQ variant, making it appropriate for non-safety-critical industrial systems with similar environmental demands.
How does the hFE binning affect circuit design?
BC857B-7-F's hFE range of 220–475 means base resistor values must be selected using hFE(min) = 220 to guarantee saturation under worst-case conditions. This avoids unintended linear-mode operation and ensures consistent switching behavior across production lots.
What is the recommended pad layout for SOT23 mounting?
Diodes recommends a 2.0 mm × 0.8 mm pad footprint with 1.35 mm X-dimension and 2.9 mm Y-dimension, per their official SOT23 outline. Use minimum 1 oz copper with thermal relief for solderability; avoid oversized pads that impede reflow profiling or cause tombstoning.
BC857B-7-F Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- 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:
- 650mV @ 5mA, 100mA
- Current - Collector Cutoff (Max):
- 15nA
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 220 @ 2mA, 5V
- Power - Max:
- 300 mW
- Frequency - Transition:
- 200MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
BC857B-7-F FAQ
1.How can I place an order for BC857B-7-F through Aetrix?
Please submit a Request for Quotation (RFQ) for BC857B-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 BC857B-7-F reliable?
The price and inventory of BC857B-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 BC857B-7-F is usually 5 days.
3.What payment methods are accepted for BC857B-7-F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC857B-7-F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BC857B-7-F?
BC857B-7-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BC857B-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 BC857B-7-F?
For technical support, including BC857B-7-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC857B-7-F requirements.
6.How does Aetrix verify that BC857B-7-F is sourced from the original manufacturer or authorized distributors?
All BC857B-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 BC857B-7-F meets industry standards.
7.What is the process for return or replacement of BC857B-7-F?
All BC857B-7-F units undergo pre-shipment inspection (PSI). If there is an issue with BC857B-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 BC857B-7-F part is unused and in its original packaging.
Return procedure for BC857B-7-F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BC857B-7-F Tags
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