onsemi BC858BLT3

Overview

BC858BLT3 from onsemi is a PNP silicon general-purpose transistor in SOT-23 package, rated for −30 V V_CEO, −100 mA I_C continuous, and 225 mW power dissipation on FR-5 board. It delivers h_FE = 220–475 at I_C = −2 mA, V_CE = −5 V, with f_T = 100 MHz and V_CE(sat) ≤ −0.65 V at I_C = −100 mA/I_B = −5 mA - used in low-voltage switching and signal amplification in automotive sensor interfaces and industrial control logic.

For engineers reviewing the BC858BLT3 datasheet, pinout, applications, or equivalent options, key selection criteria include its AEC-Q101 qualification, −30 V breakdown rating, SOT-23 footprint compatibility, DC current gain range, and thermal performance on standard PCB substrates.

Technical Context

This device operates as a discrete PNP bipolar junction transistor optimized for linear amplification and saturated switching in low-power analog and digital circuits. Its base-emitter junction supports −5.0 V reverse bias, and collector-base withstands −30 V, enabling robust operation in rail-to-rail negative supply configurations.

Designed for stable DC gain across temperature (−55°C to +150°C), it exhibits predictable V_BE(on) = −0.75 V typical at I_C = −10 mA and low output capacitance (C_ob = 4.5 pF), supporting moderate-frequency signal conditioning up to 100 MHz f_T.

Key Specifications

Pinout & Package

SOT-23 (TO-236) surface-mount plastic package, 2.90 × 1.30 × 1.00 mm, 3-pin, lead-free and RoHS compliant. Pin configuration follows Style 6 per onsemi mechanical drawing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP general-purpose transistor applications.

Compared with BC857BLT3, BC858BLT3 trades voltage headroom for optimized cost and footprint in ≤24 V systems; versus BC858CLT3, it offers more predictable gain distribution at lower test cost - making BC858BLT3 ideal for high-volume automotive and industrial signal conditioning where −30 V rating suffices.

Availability

BC858BLT3 is available at Aetrix Electronics and suitable for automotive cabin sensors, industrial PLC input stages, and portable medical instrumentation requiring stable component supply, AEC-Q101 compliance, and SOT-23 footprint consistency.

Supply support for BC858BLT3 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, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The BC858BLT3 belongs to the BC856ALT1G Series of general-purpose PNP transistors designed for cost-sensitive, high-reliability signal switching and amplification in automotive and industrial control systems.

FAQ

What is the maximum collector-emitter voltage rating for BC858BLT3?

The BC858BLT3 has a guaranteed V_CEO rating of −30 V at I_C = −10 mA, meaning it can safely block up to 30 V of reverse polarity across collector and emitter in open-emitter configuration. This rating is validated per onsemi's April 2023 datasheet revision and applies under standard test conditions with TA = 25°C. Exceeding this voltage risks irreversible breakdown and device failure.

Is BC858BLT3 suitable for automotive applications?

Yes, BC858BLT3 is AEC-Q101 qualified and PPAP capable, confirming its suitability for automotive applications including cabin sensors, body control modules, and lighting drivers. The device meets stress testing requirements for temperature cycling, humidity, and mechanical shock, and its −55°C to +150°C operating range supports under-dash and engine bay deployments. BC858BLT3 carries no "S" or "NSV" prefix but shares the same qualification baseline as automotive-grade variants in the series.

What is the DC current gain (h_FE) range for BC858BLT3?

The BC858BLT3 is binned to the "B" gain group, with h_FE specified as 220–475 at I_C = −2.0 mA and V_CE = −5.0 V. This range is measured and guaranteed per onsemi's production test flow and reflects typical variation across manufacturing lots. At higher currents (e.g., I_C = −10 mA), h_FE remains within this band but may trend toward the lower end due to early saturation effects.

Does BC858BLT3 have a Pb-free and RoHS-compliant package?

Yes, BC858BLT3 is supplied in a Pb-free, halogen-free/BFR-free SOT-23 package and is fully RoHS compliant per EU Directive 2011/65/EU. The "G" suffix in the full orderable part number (BC858BLT3G) explicitly denotes the Pb-free construction, and the device carries the appropriate marking per onsemi's packaging specifications. No lead content is present in solderable terminations or mold compound.

What is the thermal resistance (R_JA) of BC858BLT3 on FR-5 board?

The BC858BLT3 exhibits a thermal resistance of R_JA = 556 °C/W when mounted on a standard FR-5 PCB (1.0 × 0.75 × 0.062 in.) with no added copper pour. This value assumes natural convection and defines the temperature rise per watt of dissipated power. Derating begins at 1.8 mW/°C above 25°C ambient, limiting usable power to ~180 mW at 85°C case temperature.