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

Nexperia USA Inc. BC858B-QR

Name: BC858B-QR
Brand: Nexperia USA Inc.
SKU: BC858B-QR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC858B-QR

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: BC858B-QR.pdf

Description:: TRANS PNP 30V 0.1A TO-236AB

Quantity:: RFQ Add To RFQ list

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Inventory:6,484

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Product details

Overview

BC858B-QR from Nexperia is a PNP general-purpose bipolar junction transistor in SOT23 (TO-236AB) package, rated for −30 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-voltage switching or linear amplification device in automotive signal conditioning and power control circuits.

For engineers reviewing the BC858B-QR datasheet, BC858B-QR pinout, BC858B-QR application, or BC858B-QR equivalent, this page delivers verified electrical parameters, AEC-Q101 qualification status, thermal resistance (500 K/W), saturation voltage (V_CEsat ≤ −650 mV at I_C = −100 mA), and exact SOT23 pin mapping - all critical for automotive-grade PCB layout and reliability validation.

Technical Context

This PNP BJT operates with emitter-base forward bias and collector-base reverse bias in active or saturation mode. Its h_FE range (220–475) ensures predictable current amplification across −55 °C to +150 °C ambient, while V_(BR)CEO = −30 V and V_(BR)EBO = −5 V define safe operating limits for low-side switch and level-shifting topologies.

Thermal resistance R_th(j-a) = 500 K/W (FR4 PCB, single-sided, 35 µm Cu) governs power derating above 25 °C, and f_T = 100 MHz enables stable operation up to audio-frequency amplification and digital switching below 10 MHz.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−30 V: Maximum collector-emitter voltage with open base; defines safe blocking capability in low-voltage PNP switch configurations.
I_C	−100 mA: Continuous DC collector current; supports load switching up to ~100 mA in automotive sensor interfaces or LED drivers.
h_FE	220–475 at V_CE = −5 V, I_C = −2 mA: Ensures reliable base drive design margin for gain-stable amplification or saturated switching.
V_CEsat	≤ −650 mV at I_C = −100 mA, I_B = −5 mA: Low saturation voltage minimizes conduction loss in high-efficiency discrete switches.
R_th(j-a)	500 K/W: Junction-to-ambient thermal resistance on standard FR4 PCB; requires derating above 25 °C ambient for sustained 100 mA operation.
f_T	100 MHz: Transition frequency at V_CE = −5 V, I_C = −10 mA; supports stable small-signal amplification up to mid-audio band.

Pinout & Package

SOT23 (TO-236AB) plastic surface-mounted package with 3 leads; 2.8 mm × 1.4 mm footprint, 1.1 mm height, and gull-wing terminations compatible with reflow and wave 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 control.
2	Emitter (E)	Common terminal for PNP topology; connected to higher potential rail (e.g., 5 V or 3.3 V) in low-side switch applications.
3	Collector (C)	Output current path; sinks load current to ground when saturated; must remain ≤ −30 V relative to emitter under all conditions.

Key Features

Feature	Design Value
AEC-Q101 qualified	Stress-tested per Automotive Electronics Council standard for discrete semiconductors; validated for under-hood and body-control module use.
Low V_CEsat	−650 mV max at full rated I_C; reduces power dissipation in always-on or PWM-driven loads like relay drivers.
Wide temperature range	Operates from −65 °C to +150 °C junction; supports engine bay, HVAC, and lighting modules without external thermal management.
High h_FE consistency	220–475 spread at I_C = −2 mA ensures predictable base drive sizing across production lots and temperature extremes.

Applications

Automotive Door Module Switching

Industrial Sensor Signal Conditioning

Use Scenario: Controlling window lift motor enable logic via microcontroller GPIO in door control units.

IC Role / Device Role / Timing Role: PNP switch driving MOSFET gate or optocoupler input; provides level shift and current gain for 3.3 V MCU interfacing with 12 V loads.

Use Value: −650 mV V_CEsat limits power loss to <100 mW at 100 mA, enabling compact PCB layout without heatsinking in space-constrained modules.

Use Scenario: Amplifying low-level analog output from NTC temperature sensors in HVAC control boards.

IC Role / Device Role / Timing Role: Common-emitter amplifier stage with fixed bias network; provides 20–30 dB voltage gain for 0.5–5 kHz sensor signals.

Use Value: 100 MHz f_T and stable h_FE over −40 °C to +85 °C ensure distortion-free amplification across full vehicle operating range.

LED Driver for Interior Lighting

Power Supply Enable Control

Use Scenario: Driving 20 mA white LED strings in dashboard backlighting using constant-current configuration.

IC Role / Device Role / Timing Role: Emitter-follower current source; sets LED current via emitter resistor referenced to regulated 5 V rail.

Use Value: Tight h_FE tolerance (220–475) enables ±5% current accuracy without trimming, reducing BOM count in mass-produced panels.

Use Scenario: Enabling/disabling secondary 3.3 V LDO in infotainment head unit based on ignition signal.

IC Role / Device Role / Timing Role: High-side switch controlling LDO EN pin; translates 12 V ignition pulse to clean 3.3 V logic-enable edge.

Use Value: −30 V V_CEO and −5 V V_EBO withstand transients up to ISO 7637-2 Pulse 1/2a, eliminating need for external TVS in cost-sensitive designs.

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-Q	V_CEO = −45 V, h_FE = 220–475, same SOT23 package and pinout	Higher blocking voltage supports 24 V systems; identical thermal and gain behavior at 100 mA	Select when system rail exceeds 30 V or transient immunity >30 V required
BC848B-Q	NPN complement; same V_CEO = 30 V, I_C = 100 mA, h_FE = 220–475, SOT23 pinout (1=E, 2=C, 3=B)	Used in high-side switch or common-emitter amplifier where NPN topology simplifies base drive	Choose for complementary pair design or when sourcing current from ground-referenced nodes

Compared with BC857B-Q, BC858B-Q offers lower V_CEO but identical gain and saturation performance-ideal for 12 V automotive subsystems where size and cost outweigh voltage headroom needs; versus BC848B-Q, it enables high-side switching without level-shifting circuitry, reducing component count in power domain control.

Availability

BC858B-QR is available at Aetrix Electronics and suitable for automotive door modules, HVAC sensor interfaces, interior LED lighting, and power supply enable control requiring stable component supply across extended temperature ranges and AEC-Q101 compliance.

Supply support for BC858B-QR 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 efficiency technologies, delivering high-performance, reliable discrete and logic devices for automotive, industrial, and consumer markets.

The BC858-Q series belongs to Nexperia's AEC-Q101-qualified general-purpose transistor product line, engineered specifically for robust, cost-effective switching and amplification in harsh automotive environments.

FAQ

Is BC858B-QR pin-compatible with BC847B-Q?

No. BC858B-QR is a PNP transistor with pinout Base–Emitter–Collector (1–2–3), while BC847B-Q is an NPN device with pinout Emitter–Collector–Base (1–2–3) in the same SOT23 package. Swapping them without circuit redesign will cause functional failure due to reversed polarity and current flow direction.

What is the maximum allowable continuous power dissipation for BC858B-QR at 85 °C ambient?

At 85 °C ambient, derated power dissipation is 125 mW. This is calculated from P_tot = 250 mW at 25 °C and R_th(j-a) = 500 K/W: ΔT = 60 K → P = (250 mW) × (1 − 60/125) = 125 mW. Exceeding this risks junction temperature exceeding 150 °C and permanent degradation.

Does BC858B-QR support pulsed operation beyond its DC current rating?

Yes. Peak collector current I_CM is rated at −200 mA for short pulses (t_p ≤ 300 µs, duty cycle ≤ 2%). This allows brief surge handling in relay coil snubbing or inrush limiting, provided average power remains within 250 mW and thermal cycling stays within JEDEC JESD22-A108 limits.

How does the AEC-Q101 qualification impact BC858B-QR's use in non-automotive applications?

AEC-Q101 qualification confirms robustness against temperature cycling, humidity, mechanical shock, and ESD - making BC858B-QR highly reliable in industrial, medical, and aerospace applications where long-term stability and field failure avoidance are critical, even if automotive certification isn't mandated.

BC858B-QR 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):: 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:: 250 mW

Frequency - Transition:: 100MHz

Operating Temperature:: 150°C (TJ)

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: TO-236AB

BC858B-QR FAQ

1.How can I place an order for BC858B-QR through Aetrix?

Please submit a Request for Quotation (RFQ) for BC858B-QR 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 BC858B-QR reliable?

The price and inventory of BC858B-QR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC858B-QR is usually 5 days.

3.What payment methods are accepted for BC858B-QR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC858B-QR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC858B-QR?

BC858B-QR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC858B-QR 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 BC858B-QR?

For technical support, including BC858B-QR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC858B-QR requirements.

6.How does Aetrix verify that BC858B-QR is sourced from the original manufacturer or authorized distributors?

All BC858B-QR 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 BC858B-QR meets industry standards.

7.What is the process for return or replacement of BC858B-QR?

All BC858B-QR units undergo pre-shipment inspection (PSI). If there is an issue with BC858B-QR, 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 BC858B-QR part is unused and in its original packaging.

Return procedure for BC858B-QR:

1.Submit a request within 90 days.

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

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