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

Nexperia USA Inc. BC857BW/ZLF

Name: BC857BW/ZLF
Brand: Nexperia USA Inc.
SKU: BC857BW/ZLF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC857BW/ZLF

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

Package:: SC-70, SOT-323

Datasheet:: BC857BW/ZLF.pdf

Description:: TRANS SOT323

Quantity:: RFQ Add To RFQ list

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Inventory:9,997

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Product details

Overview

BC857BW/ZLF 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 220–475 at V_CE = −5 V and I_C = −2 mA. It serves as a low-power switching or linear amplification device in compact consumer, industrial, and communication signal-path circuits.

For engineers reviewing the BC857BW/ZLF datasheet, BC857BW/ZLF pinout, BC857BW/ZLF application, or BC857BW/ZLF equivalent, key selection criteria include its PNP polarity, SOT323 footprint compatibility, guaranteed h_FE range, V_CEO rating, and thermal resistance (R_th(j-a) = 625 K/W on FR4).

Technical Context

This transistor operates in active, saturation, and cutoff regions with defined absolute maximum ratings: −45 V collector-emitter voltage (open base), −50 V collector-base voltage (open emitter), and −5 V emitter-base voltage. Its h_FE variation across temperature (−55 °C to +150 °C) and collector current (100 µA to 100 mA) is characterized per Fig. 6–9 in the datasheet.

V_CE(sat) remains ≤ −250 mV at I_C = −100 mA / I_B = −5 mA, and V_BE(sat) ≤ −850 mV under same conditions. Transition frequency f_T is 100 MHz at V_CE = −5 V and I_C = −10 mA, supporting audio and low-speed digital switching applications.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−45 V - Maximum safe collector-emitter voltage with base open; defines upper rail limit in PNP switch designs.
I_C	−100 mA - Continuous DC collector current rating; sets load-driving capability in small-signal stages.
h_FE	220–475 - DC current gain at V_CE = −5 V, I_C = −2 mA; ensures predictable base drive requirements.
V_CE(sat)	≤ −250 mV - Collector-emitter saturation voltage at I_C = −100 mA / I_B = −5 mA; minimizes conduction loss in switching mode.
R_th(j-a)	625 K/W - Junction-to-ambient thermal resistance on standard FR4 PCB; informs derating above 25 °C ambient.
f_T	100 MHz - Transition frequency at V_CE = −5 V, I_C = −10 mA; supports audio amplification and <10 MHz digital switching.

Pinout & Package

SOT323 (SC-70) plastic surface-mounted package: 1.35 mm × 1.75 mm footprint, 0.95 mm height, 3-lead configuration with gull-wing terminations. Optimized for reflow soldering per IPC-7095 guidelines.

Pin/Terminal	Circuit Role	Design Meaning
1	Base (B)	Current-controlled input node; requires series resistor to limit I_B and ensure stable h_FE-based operation.
2	Emitter (E)	Common terminal for PNP topology; connects to higher potential rail in high-side switch configurations.
3	Collector (C)	Output current path; sinks current when B-E junction is forward-biased; ties to load or next stage input.

Key Features

Feature	Design Value
Low-voltage PNP switching	Rated for −45 V V_CEO, enabling use in 3.3 V, 5 V, and 12 V rail-referenced logic interfaces.
Precision h_FE binning	BC857BW grade guarantees h_FE = 220–475, reducing base resistor tolerance sensitivity in production designs.
Ultra-small footprint	SOT323 package saves >60% board area vs. SOT23, critical for space-constrained wearables and IoT nodes.
Thermally robust SMD layout	Standard FR4 footprint with 0.6 mm pad width supports automated optical inspection and high-yield reflow.

Applications

LED Driver Circuit

Level-Shifting Interface

Use Scenario: Driving discrete indicator LEDs from microcontroller GPIO pins operating at 3.3 V logic levels.

IC Role / Device Role / Timing Role: PNP switch controlling LED anode connection to V_CC; base driven by inverted MCU output.

Use Value: Low V_CE(sat) (≤ −250 mV) preserves >95% of supply voltage across LED, maximizing brightness at 20 mA.

Use Scenario: Translating 1.8 V logic signals to 5 V domains in mixed-voltage sensor subsystems.

IC Role / Device Role / Timing Role: Active-low level shifter using emitter-follower or common-emitter inversion topology.

Use Value: Guaranteed h_FE ≥ 220 ensures reliable turn-on with minimal base current, reducing MCU loading.

Audio Pre-amplifier Stage

Power Supply Enable Switch

Use Scenario: Low-noise voltage amplification of electret microphone outputs in portable audio devices.

IC Role / Device Role / Timing Role: Common-emitter amplifier biased in linear region; configured for 20–20 kHz bandwidth.

Use Value: f_T = 100 MHz and NF = 2–10 dB at 1 kHz support clean gain without high-frequency roll-off or added noise.

Use Scenario: Enabling/disabling auxiliary 3.3 V LDO outputs based on system power-state controller signals.

IC Role / Device Role / Timing Role: High-side enable switch placing BC857BW between LDO input and enable pin pull-down network.

Use Value: −45 V V_CEO margin accommodates transient overshoot on 3.3 V rails, improving reliability during hot-plug events.

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
BC857B,115 (Nexperia)	Same h_FE bin (220–475), identical SOT323 package, but marked "3B" instead of "ZLF"; RoHS-compliant, no halogen restriction noted.	No functional difference; ZLF denotes specific tape-and-reel packaging per customer order code, not electrical variation.	Select BC857B,115 for standard distribution; BC857BW/ZLF when ZLF-specific reel labeling or traceability is required.
MMBT3906LT1G (onsemi)	Lower V_CEO (−40 V), wider h_FE range (100–300), same SOT23-3 package (not pin-compatible with SOT323).	Requires PCB redesign due to larger SOT23 footprint and different pinout (E-B-C vs. B-E-C); unsuitable for drop-in replacement.	Choose only if SOT23 layout exists and −40 V rating suffices; verify thermal performance (R_th(j-a) ≈ 400 K/W) under same board conditions.

Compared with BC857BW/ZLF, BC857B,115 offers identical electrical behavior and mechanical fit, while MMBT3906LT1G demands layout changes and provides lower voltage margin but broader availability in high-volume channels.

Availability

BC857BW/ZLF is available at Aetrix Electronics and suitable for LED driver circuits, level-shifting interfaces, audio pre-amplifier stages, and power supply enable switches requiring stable component supply, consistent h_FE binning, and SOT323 footprint reliability.

Supply support for BC857BW/ZLF 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 leading semiconductor manufacturer specializing in high-volume, high-reliability discrete and logic devices, headquartered in Nijmegen, Netherlands.

The BC857BW belongs to Nexperia's BC856W/BC857W/BC858W family of general-purpose PNP transistors designed for cost-sensitive, space-constrained switching and amplification in consumer, computing, and industrial electronics.

FAQ

What is the maximum allowable junction temperature for BC857BW/ZLF?

The absolute maximum junction temperature (T_j) is 150 °C, as specified in Table 6 of the Nexperia datasheet. Operation above this value risks permanent degradation. Derating is required above 25 °C ambient, using R_th(j-a) = 625 K/W on standard FR4 PCB to calculate safe I_C limits.

Is BC857BW/ZLF pin-compatible with BC847BW?

No - BC857BW/ZLF is a PNP transistor, while BC847BW is its NPN complement. Though both share the SOT323 package and identical pinout (B-E-C), their polarity reversal means direct substitution would invert circuit function and likely cause failure unless topology is redesigned.

Does BC857BW/ZLF meet automotive AEC-Q101 requirements?

No - BC857BW/ZLF is not AEC-Q101 qualified. The Nexperia datasheet explicitly states these parts are "non-automotive qualified products" and are unsuitable for safety-critical or life-support systems. Automotive-grade alternatives require explicit AEC-Q101 certification in the ordering code and datasheet.

What does the "ZLF" suffix indicate in BC857BW/ZLF?

"ZLF" is a Nexperia internal packaging and marking code indicating tape-and-reel delivery with specific reel size (10,000 pcs per 12 mm tape), humidity-sensitive level (MSL3), and Pb-free/RoHS-compliant finish. It does not alter electrical specifications versus BC857BW without suffix.

BC857BW/ZLF Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: -

Current - Collector (Ic) (Max):: -

Voltage - Collector Emitter Breakdown (Max):: -

Vce Saturation (Max) @ Ib, Ic:: -

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: -

Power - Max:: -

Frequency - Transition:: -

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323

BC857BW/ZLF FAQ

1.How can I place an order for BC857BW/ZLF through Aetrix?

Please submit a Request for Quotation (RFQ) for BC857BW/ZLF 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 BC857BW/ZLF reliable?

The price and inventory of BC857BW/ZLF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC857BW/ZLF is usually 5 days.

3.What payment methods are accepted for BC857BW/ZLF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC857BW/ZLF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC857BW/ZLF?

BC857BW/ZLF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC857BW/ZLF 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 BC857BW/ZLF?

For technical support, including BC857BW/ZLF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC857BW/ZLF requirements.

6.How does Aetrix verify that BC857BW/ZLF is sourced from the original manufacturer or authorized distributors?

All BC857BW/ZLF 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 BC857BW/ZLF meets industry standards.

7.What is the process for return or replacement of BC857BW/ZLF?

All BC857BW/ZLF units undergo pre-shipment inspection (PSI). If there is an issue with BC857BW/ZLF, 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 BC857BW/ZLF part is unused and in its original packaging.

Return procedure for BC857BW/ZLF:

1.Submit a request within 90 days.

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

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