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onsemi BC858BWT1
- Part No.:
- BC858BWT1
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- SC-70, SOT-323
- Datasheet:
-
BC858BWT1.pdf
- Description:
- TRANS PNP 30V 0.1A SC70-3
- Quantity:
- Payment:
- Shipping:
Inventory:8,787
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Product details
Overview
BC858BWT1 from onsemi is a PNP silicon general-purpose transistor in SC-70/SOT-323 package, rated for VCEO = −30 V, IC = −100 mA, and hFE = 220–475 at IC = −2.0 mA, used in low-power amplifier and switching circuits on compact PCBs.
For engineers reviewing the BC858BWT1 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical ratings, terminal mapping, thermal behavior, and direct alternative options for discrete PNP signal-level design.
Technical Context
The BC858BWT1 operates as a medium-gain, low-power PNP bipolar junction transistor optimized for linear amplification and saturated switching in surface-mount applications. Its VCEO = −30 V and VCBO = −30 V define safe operation under moderate reverse bias, while fT = 100 MHz supports audio and low-speed digital signal handling.
Thermal performance is constrained by RJA = 883°C/W on FR-5 board and PD = 150 mW maximum dissipation. The device exhibits VBE(sat) = −0.7 V (typ) at IC/IB = 10 and Cob = 4.5 pF at VCB = −10 V, enabling predictable small-signal behavior in bias-stable configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | −30 V - Maximum collector-emitter voltage before breakdown; sets upper limit for supply rail headroom in PNP common-emitter stages. |
| IC (cont.) | −100 mA - Continuous collector current rating; defines maximum DC load drive capability without thermal derating. |
| hFE | 220–475 @ IC = −2.0 mA - DC current gain range ensures stable biasing in amplifier designs with minimal base drive requirements. |
| fT | 100 MHz - Current-gain bandwidth product; confirms suitability for audio-frequency amplification and low-speed switching (<10 MHz). |
| Cob | 4.5 pF @ VCB = −10 V - Output capacitance limits high-frequency gain roll-off and affects stability in feedback networks. |
| PD | 150 mW @ TA = 25°C - Power dissipation ceiling on standard FR-5 board; requires layout-aware thermal relief for sustained operation. |
| RJA | 883°C/W - Junction-to-ambient thermal resistance; indicates significant self-heating under load, necessitating conservative power budgeting. |
Pinout & Package
BC858BWT1 uses the SC-70/SOT-323 package (Case 419, Style 3), a 3-pin, low-profile surface-mount outline measuring 2.1 × 1.24 × 0.9 mm (L × W × H), optimized for space-constrained consumer and portable electronics.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Base | Control terminal for forward-biased PNP operation; requires negative base current relative to emitter to enable conduction. |
| 2 | Emiter | Current source terminal in PNP configuration; connected to higher potential (e.g., VCC) in common-emitter amplifier topologies. |
| 3 | Collector | Current sink terminal; output node where amplified or switched current flows toward lower-potential load or ground reference. |
Key Features
| Feature | Design Value |
|---|---|
| Pb-free packaging | Complies with RoHS Directive 2011/65/EU; eliminates lead contamination risk during reflow and end-of-life recycling. |
| Low thermal resistance footprint | SC-70 package enables direct thermal coupling to copper pour; supports >100 mA pulsed operation with localized heatsinking. |
| High hFE consistency | 220–475 gain spread at IC = −2.0 mA reduces need for emitter degeneration in bias networks across production lots. |
| Low VCE(sat) | −0.3 V (typ) @ IC = −10 mA / IB = −0.5 mA minimizes voltage drop in saturated switch applications, improving efficiency. |
| Controlled Cob | 4.5 pF max ensures predictable Miller effect in amplifier stages, simplifying frequency compensation for unity-gain stability. |
Applications
| Audio Pre-amplifier Stage | Level Translation Circuit |
|---|---|
Use Scenario: Amplifying microphone-level signals (−10 to −20 mV) in portable voice recorders before ADC input. IC Role / Device Role / Timing Role: PNP common-emitter small-signal amplifier providing 20–30 dB voltage gain with low noise figure (NF ≤ 10 dB). Use Value: High hFE and low Cob maintain wideband fidelity up to 20 kHz without phase distortion or gain peaking. |
Use Scenario: Converting 3.3 V logic-high signals to −5 V referenced outputs for legacy analog interface ICs. IC Role / Device Role / Timing Role: Saturated PNP level shifter operating in cutoff/saturation with <100 ns transition time. Use Value: VCE(sat) ≤ −0.65 V ensures output swing stays within −4.35 V minimum, meeting TTL-compatible thresholds. |
| LED Driver (Low-Side Switch) | Current Mirror Reference |
Use Scenario: Driving indicator LEDs (20 mA, 2.1 V VF) from microcontroller GPIO pins with active-low control. IC Role / Device Role / Timing Role: Low-power PNP switch sinking current from VCC through LED to MCU pin (active-low enable). Use Value: IC = −100 mA rating provides 5× safety margin over 20 mA load; SC-70 footprint saves board area vs. SOT-23. |
Use Scenario: Building matched current sources in precision sensor signal conditioning circuits (e.g., RTD bridges). IC Role / Device Role / Timing Role: PNP current mirror master transistor establishing stable reference current via matched hFE and VBE. Use Value: Tight hFE range (220–475) and low VBE(on) variation (−0.75 to −0.82 V) minimize mirror ratio error below ±3%. |
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 |
|---|---|---|---|
| BC857BWT1 | VCEO = −45 V, VCBO = −50 V, hFE = 220–475 @ IC = −2.0 mA - higher voltage rating but identical gain and package. | Preferred where supply rails exceed −30 V (e.g., −42 V telecom line cards); same thermal and switching behavior. | Select BC857BWT1 when system VCC > 30 V; otherwise BC858BWT1 offers optimal cost/voltage match for ≤30 V designs. |
| MMBT3906LT1G | VCEO = −40 V, hFE = 100–300 @ IC = −10 mA - wider gain tolerance, different test condition, same SC-70 package. | Used in legacy designs requiring MIL-PRF-19500 qualified equivalents; slightly lower fT (250 MHz vs. 100 MHz) but broader gain spread. | Choose MMBT3906LT1G only if cross-reference validation exists in existing BOM; BC858BWT1 provides tighter hFE control for new designs. |
Compared with BC857BWT1 and MMBT3906LT1G, BC858BWT1 delivers the narrowest voltage rating (−30 V) but tightest hFE consistency for stable biasing in battery-powered audio and sensing nodes where supply headroom is constrained.
Availability
BC858BWT1 is available at Aetrix Electronics and suitable for audio pre-amplifiers, level translation circuits, LED drivers, current mirrors, and low-power switching applications requiring stable component supply and RoHS-compliant packaging.
Supply support for BC858BWT1 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.
The BC858BWT1 belongs to onsemi's BC856/BC857/BC858 series of general-purpose PNP transistors designed for reliable, low-cost amplification and switching in space-constrained consumer and portable electronics.
FAQ
What is the maximum continuous collector current for BC858BWT1?
The BC858BWT1 has a maximum continuous collector current (IC) of −100 mA at TA = 25°C. This rating assumes adequate PCB copper area for heat dissipation; derating is required above 25°C ambient per the RJA = 883°C/W thermal resistance. Exceeding −100 mA risks thermal runaway or permanent degradation of the BC858BWT1.
Does BC858BWT1 support Pb-free soldering processes?
Yes, BC858BWT1 is offered in both standard and Pb-free versions (e.g., BC858BWT1G). The device complies with JEDEC J-STD-020 moisture sensitivity level 1 (MSL1) and withstands peak reflow temperatures up to 260°C, making it compatible with standard lead-free soldering profiles without compromising reliability of the BC858BWT1.
What is the typical DC current gain (hFE) of BC858BWT1 at 2 mA collector current?
The BC858BWT1 exhibits a typical DC current gain (hFE) of 220–475 when tested at IC = −2.0 mA and VCE = −5.0 V. This range reflects production lot variation; design margins should accommodate the full min/max span to ensure consistent biasing across all units of BC858BWT1 deployed in production.
Can BC858BWT1 be used in high-frequency amplifier designs?
The BC858BWT1 has an fT of 100 MHz, making it suitable for audio-frequency amplification (up to 20 kHz) and low-speed digital switching (<10 MHz), but not for RF or GHz-range applications. Its Cob = 4.5 pF contributes to predictable roll-off, so the BC858BWT1 is best applied where bandwidth demands remain well below its fT limit.
How is the pinout configured for BC858BWT1 in the SC-70 package?
The BC858BWT1 uses SC-70/SOT-323 package with pin 1 = Base, pin 2 = Emitter, pin 3 = Collector (viewed from top, marking side up, leads down). This pinout is standardized across the BC856/BC857/BC858 series; incorrect orientation during placement will result in open-circuit or reverse-biased operation of the BC858BWT1.
BC858BWT1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- SC-70, SOT-323
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Transistor Type:
- PNP
- Current - Collector (Ic) (Max):
- 100 mA
- Voltage - Collector Emitter Breakdown (Max):
- 30 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:
- 150 mW
- Frequency - Transition:
- 100MHz
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SC-70-3 (SOT323)
BC858BWT1 FAQ
1.How can I place an order for BC858BWT1 through Aetrix?
Please submit a Request for Quotation (RFQ) for BC858BWT1 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 BC858BWT1 reliable?
The price and inventory of BC858BWT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC858BWT1 is usually 5 days.
3.What payment methods are accepted for BC858BWT1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC858BWT1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BC858BWT1?
BC858BWT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BC858BWT1 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 BC858BWT1?
For technical support, including BC858BWT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC858BWT1 requirements.
6.How does Aetrix verify that BC858BWT1 is sourced from the original manufacturer or authorized distributors?
All BC858BWT1 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 BC858BWT1 meets industry standards.
7.What is the process for return or replacement of BC858BWT1?
All BC858BWT1 units undergo pre-shipment inspection (PSI). If there is an issue with BC858BWT1, 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 BC858BWT1 part is unused and in its original packaging.
Return procedure for BC858BWT1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BC858BWT1 Tags
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