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

Nexperia USA Inc. BC857W-QF

Name: BC857W-QF
Brand: Nexperia USA Inc.
SKU: BC857W-QF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC857W-QF

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

Package:: SC-70, SOT-323

Datasheet:: BC857W-QF.pdf

Description:: TRANS PNP 45V 0.1A SOT-323

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC857W-Q from Nexperia is a PNP general-purpose bipolar junction transistor in SOT323 (SC-70) package, rated for −45 V V_CEO, −100 mA I_C, and DC current gain (h_FE) of 125–800 at V_CE = −5 V, I_C = −2 mA. It serves as a low-power switching or linear amplification device in automotive signal conditioning, sensor interface, and power management circuits.

For engineers reviewing the BC857W-Q datasheet, BC857W-Q pinout, BC857W-Q application, or BC857W-Q equivalent, key selection criteria include its AEC-Q101 qualification, −45 V breakdown rating, 200 mW power dissipation, SC-70 footprint compatibility, and h_FE binning options (W/AW/BW/CW) supporting precision biasing in space-constrained automotive modules.

Technical Context

This PNP transistor operates with emitter-base forward bias and collector-base reverse bias in standard common-emitter configuration. Its thermal resistance R_th(j-a) is 625 K/W on FR4 PCB, and it supports pulsed operation up to 200 mA I_CM with ≤300 µs pulse width and duty cycle ≤0.02.

Electrical behavior is defined by V_BE ≈ −650 mV at I_C = −10 mA, V_CE(sat) ≤ −600 mV at I_C = −100 mA / I_B = −5 mA, and f_T ≥ 100 MHz at V_CE = −5 V, I_C = −10 mA - enabling stable small-signal amplification and fast switching below 10 MHz.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−45 V: Maximum safe collector-emitter voltage with open base; defines upper rail limit in PNP switch designs.
I_C	−100 mA continuous: Absolute max DC collector current; sets load-driving capability in discrete logic-level interfaces.
h_FE	125–800 at V_CE = −5 V, I_C = −2 mA: Wide DC gain range enables flexible bias network design without external feedback.
P_tot	200 mW at T_amb ≤ 25 °C: Thermal limit on FR4 PCB dictates derating above 25 °C; requires layout-aware copper area planning.
V_BE(sat)	≤ −850 mV at I_C = −100 mA, I_B = −5 mA: Confirms sufficient base drive margin for hard saturation in switching applications.
f_T	≥ 100 MHz: Supports RF-coupled preamplifier stages and high-speed digital signal inversion up to ~10 MHz.
R_th(j-a)	625 K/W: Junction-to-ambient thermal resistance on standard FR4; informs heatsinking need for sustained >50 mA operation.

Pinout & Package

SOT323 (SC-70) plastic surface-mounted package: 1.35 mm × 1.75 mm footprint, 0.95 mm height, 3-terminal leadframe with gull-wing leads; optimized for reflow soldering per IPC-7095.

Pin/Terminal	Circuit Role	Design Meaning
1	Base (B)	Current-controlled input node; requires series resistor to limit I_B ≤ −200 mA peak and ensure h_FE-based I_C scaling.
2	Emitter (E)	Common reference terminal; connected to higher potential rail in PNP switch; must handle full load current path.
3	Collector (C)	Output current sink node; ties to load and lower-potential rail; voltage swing limited by V_CEO = −45 V rating.

Key Features

Feature	Design Value
AEC-Q101 qualified	Stable operation across −65 °C to +150 °C ambient; certified for under-hood automotive modules without additional qualification effort.
Low-profile SOT323	1.35 mm × 1.75 mm footprint saves board space vs. SOT23; compatible with 0.5 mm pitch reflow profiles and AOI inspection.
Wide h_FE binning	Four gain variants (W/AW/BW/CW) allow precise current mirror matching or predictable saturation in production batches.
Low V_CE(sat)	≤ −600 mV at I_C = −100 mA ensures <100 mW conduction loss in switching mode; reduces thermal stress in dense layouts.
High f_T	≥ 100 MHz enables use in audio preamps, clock buffers, and fast GPIO inverters without bandwidth limitation.

Applications

Automotive Door Module

Industrial Sensor Interface

Use Scenario: Level-shifting and current amplification for Hall-effect sensor output signals in door latch position detection.

IC Role / Device Role / Timing Role: PNP switch driving pull-up network for open-collector sensor outputs; provides rail-to-rail voltage translation between 5 V microcontroller and 12 V body domain.

Use Value: −45 V V_CEO withstands load-dump transients; AEC-Q101 rating eliminates need for separate qualification testing.

Use Scenario: Amplifying low-current analog outputs from thermistor-based temperature sensors in PLC analog input cards.

IC Role / Device Role / Timing Role: Common-emitter amplifier stage with emitter degeneration for stable DC gain and linearity over −40 °C to +85 °C.

Use Value: h_FE = 125–800 allows single-binning flexibility across sensor sensitivity ranges; 200 mW P_tot supports continuous operation without heatsink.

Consumer Audio Bias Network

Medical Wearable Power Control

Use Scenario: Setting quiescent current in Class-A headphone amplifier output stage using matched PNP/NPN pairs.

IC Role / Device Role / Timing Role: Current source element in bias generator circuit; delivers stable I_C independent of supply ripple.

Use Value: Low V_BE variation (±50 mV) across temperature ensures consistent bias point; f_T ≥ 100 MHz prevents phase shift in audio band.

Use Scenario: Enabling/disabling power to low-noise analog front-end in ECG patch devices via microcontroller GPIO.

IC Role / Device Role / Timing Role: High-side switch controlling 3.3 V rail to ADC and op-amp section; driven by active-low enable signal.

Use Value: −600 mV V_CE(sat) limits dropout to <0.6 V at 50 mA, preserving headroom for rail-sensitive analog ICs; SC-70 size fits compact flex PCB.

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
BC847W-Q	NPN complement; same package, gain binning, and AEC-Q101 rating but opposite polarity.	Requires circuit topology reversal (e.g., low-side vs. high-side switching); not drop-in for PNP positions.	Select when NPN topology is preferred or complementary pairing is needed in differential stages.
MMBT3906	Same V_CEO (−40 V), but wider V_CEO tolerance (−40 V vs. −45 V), lower h_FE min (100 vs. 125), and no AEC-Q101 certification.	Lacks automotive qualification; suitable only for commercial-grade consumer or industrial equipment.	Choose for cost-sensitive non-automotive designs where AEC-Q101 is not mandated and gain margin is acceptable.

Compared with BC847W-Q and MMBT3906, BC857W-Q uniquely combines AEC-Q101 compliance, −45 V breakdown, and 125–800 h_FE in SC-70 - making it the only option qualified for direct replacement in automotive high-reliability PNP switching roles without redesign.

Availability

BC857W-Q is available at Aetrix Electronics and suitable for automotive body control modules, industrial sensor signal chains, and medical wearable power sequencing requiring stable component supply and long-term lifecycle support.

Supply support for BC857W-Q 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 essential semiconductors, delivering high-performance, reliable components for automotive, industrial, and consumer markets.

The BC857W-Q belongs to Nexperia's AEC-Q101-qualified general-purpose transistor family, engineered for robustness in harsh environments and designed to replace legacy through-hole transistors in space-constrained automotive electronics.

FAQ

What is the maximum allowable junction temperature for BC857W-Q?

The absolute maximum junction temperature (T_j) is 150 °C, as specified in Table 6 of the datasheet. Operation beyond this limit risks permanent degradation of h_FE and increased leakage. Derating is required above 25 °C ambient per the 625 K/W thermal resistance; for example, at 85 °C ambient, maximum usable power drops to ~110 mW.

Does BC857W-Q support pulsed current operation beyond its DC rating?

Yes - BC857W-Q supports peak collector current (I_CM) of −200 mA under pulsed conditions with t_p ≤ 300 µs and duty cycle ≤ 0.02, as confirmed in Table 2 and Table 6. This enables short-duration surge handling in motor driver gate control or LED flash circuits without thermal runaway.

How does the BC857W-Q marking code '3H%' correspond to the part number?

The top-side marking '3H%' identifies BC857W-Q per Table 5: '3H' is the unique code for this variant, and '%' is a placeholder for the manufacturing site identifier. This marking is laser-etched on the SOT323 package and verified during automated optical inspection (AOI) in production.

Can BC857W-Q be used in linear amplifier configurations?

Yes - BC857W-Q is characterized for linear operation with V_CE = −5 V and I_C = −2 mA, showing h_FE = 125–800 and noise figure NF = 2–10 dB at 1 kHz. Its f_T ≥ 100 MHz and low C_c = 3 pF support stable mid-band amplification up to ~10 MHz when properly biased with emitter degeneration.

BC857W-QF Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: -

Package/Case:: SC-70, SOT-323

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:: 600mV @ 5mA, 100mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 125 @ 2mA, 5V

Power - Max:: 200 mW

Frequency - Transition:: 100MHz

Operating Temperature:: 150°C (TJ)

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323

BC857W-QF FAQ

1.How can I place an order for BC857W-QF through Aetrix?

Please submit a Request for Quotation (RFQ) for BC857W-QF 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 BC857W-QF reliable?

The price and inventory of BC857W-QF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC857W-QF is usually 5 days.

3.What payment methods are accepted for BC857W-QF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC857W-QF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC857W-QF?

BC857W-QF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC857W-QF 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 BC857W-QF?

For technical support, including BC857W-QF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC857W-QF requirements.

6.How does Aetrix verify that BC857W-QF is sourced from the original manufacturer or authorized distributors?

All BC857W-QF 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 BC857W-QF meets industry standards.

7.What is the process for return or replacement of BC857W-QF?

All BC857W-QF units undergo pre-shipment inspection (PSI). If there is an issue with BC857W-QF, 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 BC857W-QF part is unused and in its original packaging.

Return procedure for BC857W-QF:

1.Submit a request within 90 days.

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

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