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Nexperia USA Inc. BC857B,235
- Part No.:
- BC857B,235
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Bipolar Transistors
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
BC857B,235.pdf
- Description:
- TRANS PNP 45V 0.1A TO-236AB
- Quantity:
- Payment:
- Shipping:
Inventory:8,629
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Product details
Overview
BC857B,235 from Nexperia is a PNP general-purpose bipolar junction transistor in SOT23 (TO-236AB) package, rated for −45 V VCEO, −100 mA IC, and 220–475 hFE at VCE = −5 V, IC = −2 mA. It serves as a low-voltage switching or small-signal amplification device in discrete logic interfaces, level shifters, and LED driver stages.
For engineers reviewing the BC857B,235 datasheet, BC857B,235 pinout, BC857B,235 application, or BC857B,235 equivalent, this page delivers verified pin functions, thermal resistance (500 K/W), saturation voltage (−250 mV to −650 mV at IC = −100 mA), noise figure (2–10 dB), and validated alternatives for discrete BJT replacement in cost-sensitive consumer and industrial PCBs.
Technical Context
This PNP transistor operates with open-base collector-emitter breakdown of −45 V and emitter-base breakdown of −5 V, supporting reliable cutoff and active-region biasing in low-power analog and digital circuits. Its hFE range (220–475) ensures consistent current gain across production lots under standard bias conditions (VCE = −5 V, IC = −2 mA).
Thermal performance is defined for FR4 PCB mounting: Rth(j-a) = 500 K/W, enabling operation up to Tj = 150 °C with ambient limits from −65 °C to +150 °C. Transition frequency fT reaches 100 MHz at VCE = −5 V, IC = −10 mA, confirming suitability for audio-frequency amplification and moderate-speed switching.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | −45 V - Maximum safe collector-emitter voltage with base open; defines upper rail limit in PNP switch configurations. |
| IC | −100 mA - Continuous DC collector current rating; sets maximum load drive capability in linear or saturated operation. |
| hFE | 220–475 - DC current gain at VCE = −5 V, IC = −2 mA; determines base drive resistor sizing for predictable switching. |
| VCE(sat) | −250 mV to −650 mV - Collector-emitter saturation voltage at IC = −100 mA, IB = −5 mA; directly impacts power loss and voltage headroom in on-state. |
| fT | 100 MHz - Transition frequency at VCE = −5 V, IC = −10 mA; confirms usable bandwidth for audio and low-speed digital signal conditioning. |
| Rth(j-a) | 500 K/W - Junction-to-ambient thermal resistance on standard FR4 PCB; informs heatsinking requirements and power derating above 25 °C. |
| Cc | 4.5 pF - Collector capacitance at VCB = −10 V; affects high-frequency response and Miller effect in amplifier stages. |
Pinout & Package
SOT23 (TO-236AB) plastic surface-mounted package with 3 leads; 1.9 mm × 1.1 mm footprint, 0.45 mm nominal thickness, and tin-plated copper traces per JEDEC standard.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Base (B) | Control terminal for forward-biasing the emitter-base junction; requires current-limited drive to achieve target IC. |
| 2 | Emitter (E) | Current source terminal in PNP configuration; connected to higher potential rail in common-emitter switches. |
| 3 | Collector (C) | Current sink terminal; carries load current to ground or lower-potential node in typical switching topologies. |
Key Features
| Feature | Design Value |
|---|---|
| Low-voltage PNP switching | Rated for −45 V VCEO and −5 V VEBO, enabling use in 3.3 V/5 V rail systems with margin against transients. |
| Precision hFE binning | 220–475 gain range ensures predictable base drive requirements without post-layout trimming. |
| Low saturation voltage | VCE(sat) ≤ −650 mV at IC = −100 mA reduces conduction loss and self-heating in compact layouts. |
| High-frequency capability | fT = 100 MHz supports stable operation in audio preamps and clock buffer stages up to ~10 MHz. |
| Industry-standard SOT23 footprint | Compatible with automated pick-and-place and reflow processes using IPC-7351-compliant land patterns. |
Applications
| LED Driver Stage | Level Shifter Interface |
|---|---|
|
Use Scenario: Driving 20 mA indicator LEDs from 3.3 V microcontroller GPIO pins with inverted logic. IC Role / Device Role / Timing Role: PNP switch configured in common-emitter mode, sinking current from VCC through LED to collector. Use Value: VCE(sat) ≤ −650 mV ensures ≥2.65 V forward drop across LED at full brightness, maintaining visibility without excessive heat. |
Use Scenario: Translating 1.8 V logic outputs to 5 V-compatible inputs in mixed-voltage MCU peripherals. IC Role / Device Role / Timing Role: Active-low level shifter using BC857B as emitter-follower with base biased to 5 V reference. Use Value: hFE ≥ 220 guarantees minimal base current draw (<5 µA), preserving source drive strength and timing integrity. |
| Discrete Logic Inverter | Audio Signal Amplifier |
|
Use Scenario: Constructing non-inverting buffers or NAND gates in prototyping boards where IC-level integration is impractical. IC Role / Device Role / Timing Role: PNP-based saturated switch with pull-up resistor, delivering rail-to-rail output swing. Use Value: Fast turn-off due to low Cc (4.5 pF) enables propagation delays <100 ns, suitable for <1 MHz digital control signals. |
Use Scenario: Low-noise preamplification of electret microphone signals prior to ADC sampling in portable devices. IC Role / Device Role / Timing Role: Common-emitter amplifier biased in active region with emitter degeneration resistor. Use Value: Noise figure of 2–10 dB at 1 kHz ensures SNR >60 dB in 20 Hz–20 kHz band without requiring op-amp complexity. |
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 |
|---|---|---|---|
| BC857BW,115 | Same die, but in SOT323 package (smaller footprint, higher Rth(j-a) = 625 K/W). | Preferred for ultra-dense layouts where board space is constrained, but thermal derating required above 60 mA. | Select when PCB area is critical and average IC remains ≤60 mA with forced airflow or copper pour. |
| MMBT3906LT1G | Higher VCEO (−40 V), wider hFE range (100–300), and slightly higher VCE(sat) (−400 mV typ). | Better suited for legacy designs requiring direct drop-in replacement with looser gain tolerance. | Choose when interoperability with older schematics is mandatory and gain consistency is secondary to footprint compatibility. |
Compared with BC857B,235, BC857BW,115 trades thermal performance for miniaturization, while MMBT3906LT1G offers broader gain tolerance at the expense of tighter saturation voltage control-making BC857B,235 optimal for new designs prioritizing predictable drive and thermal margin in SOT23-constrained spaces.
Availability
BC857B,235 is available at Aetrix Electronics and suitable for LED driver stages, level shifter interfaces, discrete logic inverters, and audio signal amplifiers requiring stable component supply across high-mix, low-volume production runs.
Supply support for BC857B,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 semiconductor expert focused on high-volume, high-reliability discrete and logic devices, with manufacturing rooted in process control and automotive-grade quality systems.
The BC856/BC857/BC858 series targets cost-sensitive, space-constrained applications in consumer electronics and industrial controls where robust PNP switching and amplification are needed without premium packaging or qualification.
FAQ
What is the maximum allowable junction temperature for BC857B,235?
The absolute maximum junction temperature (Tj) is 150 °C, as specified in Table 6 of the Nexperia datasheet Rev. 9. Operation beyond this limit risks permanent degradation of hFE and increased leakage. Derating begins at Tamb > 25 °C using Rth(j-a) = 500 K/W on standard FR4 PCB.
Can BC857B,235 replace BC857C in a circuit?
No-BC857C has hFE = 420–800 (vs. 220–475 for BC857B), resulting in significantly higher gain and different bias point stability. Substituting without recalculating base resistors may cause saturation failure or thermal runaway in linear applications.
Is BC857B,235 qualified for automotive applications?
No-per Section 14 of the datasheet, BC857B,235 is explicitly marked "non-automotive qualified." It lacks AEC-Q101 stress testing and is not warranted for safety-critical or engine-compartment environments. Automotive alternatives require the "-Q" suffix (e.g., BC857B-Q).
What is the recommended soldering profile for BC857B,235?
Nexperia specifies reflow soldering per Fig. 15: peak temperature ≤260 °C, time above 217 °C ≤60 s, and ramp rate ≤3 °C/s. Wave soldering uses Fig. 16 footprint with preheat ≤150 °C and contact time ≤5 s. Lead-free compatible per JEDEC J-STD-020.
BC857B,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:
- 650mV @ 5mA, 100mA
- Current - Collector Cutoff (Max):
- 15nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 220 @ 2mA, 5V
- Power - Max:
- 250 mW
- Frequency - Transition:
- 100MHz
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-236AB
BC857B,235 FAQ
1.How can I place an order for BC857B,235 through Aetrix?
Please submit a Request for Quotation (RFQ) for BC857B,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 BC857B,235 reliable?
The price and inventory of BC857B,235 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC857B,235 is usually 5 days.
3.What payment methods are accepted for BC857B,235?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC857B,235 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BC857B,235?
BC857B,235 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BC857B,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 BC857B,235?
For technical support, including BC857B,235 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC857B,235 requirements.
6.How does Aetrix verify that BC857B,235 is sourced from the original manufacturer or authorized distributors?
All BC857B,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 BC857B,235 meets industry standards.
7.What is the process for return or replacement of BC857B,235?
All BC857B,235 units undergo pre-shipment inspection (PSI). If there is an issue with BC857B,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 BC857B,235 part is unused and in its original packaging.
Return procedure for BC857B,235:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BC857B,235 Tags
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MMBT3906LT1G
onsemi
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MMBT3904-7-F
Diodes Incorporated
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MMBT3904LT1G
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MMBT3906-7-F
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MMBT3904-TP
Micro Commercial Co
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MMBT2222A-7-F
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BC846BLT1G
onsemi
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BC847B,215
Nexperia USA Inc.
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SMMBT3904LT1G
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MMBTA06LT1G
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MMBT2222ALT1G
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