onsemi BC847BLT3

Overview

BC847BLT3 from onsemi is an NPN general-purpose silicon transistor in SOT-23 package, rated for 45 V_CEO, 100 mA continuous collector current, and 225 mW power dissipation on FR-5 board. It delivers DC current gain (h_FE) of 200–450 at I_C = 2.0 mA / V_CE = 5.0 V, with V_CE(sat) ≤ 0.25 V at I_C = 10 mA / I_B = 0.5 mA - used in low-voltage signal switching and biasing circuits in consumer and industrial control modules.

For engineers reviewing the BC847BLT3 datasheet, pinout, applications, or equivalent options, key selection criteria include its guaranteed h_FE range (B-grade), SOT-23 thermal performance (R_JA = 556 °C/W), ESD robustness (>4000 V HBM), Pb-free RoHS compliance, and validated safe operating area up to 45 V / 100 mA.

Technical Context

This device operates as a medium-gain, low-power NPN bipolar junction transistor optimized for linear amplification and digital switching in ambient temperatures from −55 °C to +150 °C. Its base-emitter turn-on voltage is 580–700 mV at I_C = 2.0 mA, and it maintains f_T = 100 MHz at I_C = 10 mA / V_CE = 5.0 V - supporting audio preamplifier and oscillator buffer stages.

Thermal design relies on FR-5 PCB layout per Note 1: 225 mW max dissipation derates at 1.8 mW/°C above 25 °C, with junction-to-ambient resistance fixed at 556 °C/W. The SOT-23 package uses standard pinout (1=Base, 2=Emitter, 3=Collector) and supports reflow soldering per J-STD-020 moisture sensitivity level 1.

Key Specifications

Pinout & Package

SOT-23 (TO-236) package, 3-pin surface-mount, case 318-08, moisture sensitivity level 1, Pb-free/RoHS-compliant. Dimensions: 2.90 × 1.30 × 1.00 mm (L × W × H), pin pitch 1.90 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC847BLT3, BC847BMTF offers identical performance in a different packaging format, while MMBT3904LT1G extends voltage capability to 60 V with minor trade-offs in saturation voltage - both retain SOT-23 compatibility and B-grade gain binning.

Availability

BC847BLT3 is available at Aetrix Electronics and suitable for LED driver circuits, signal level shifting, audio pre-amplifier stages, and power supply enable switches requiring stable component supply, long-term manufacturability, and RoHS-compliant sourcing.

Supply support for BC847BLT3 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, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and IoT applications.

The BC847BLT3 belongs to onsemi's BC846–BC850 family of general-purpose NPN transistors, designed for cost-sensitive, high-volume signal switching and amplification in consumer electronics and industrial controls.

FAQ

What is the maximum collector-emitter voltage rating for BC847BLT3?

The BC847BLT3 has a maximum collector-emitter voltage (V_CEO) rating of 45 V. This value is specified under test conditions of I_C = 10 mA and defines the absolute maximum DC voltage that can be applied between collector and emitter with the base open. Exceeding this rating risks avalanche breakdown and permanent device damage. Designers should maintain at least 20% derating margin (i.e., ≤36 V) in production systems for reliability.

Does BC847BLT3 support lead-free soldering processes?

Yes, BC847BLT3 is Pb-free and RoHS-compliant, qualified for standard lead-free reflow soldering per J-STD-020. Its moisture sensitivity level is 1, meaning it can be stored indefinitely at ≤30 °C/60% RH without dry-pack requirements. The device withstands peak reflow temperatures up to 260 °C for 10 seconds, matching IPC Class 3 assembly standards - confirmed in onsemi's official packaging and soldering documentation.

What is the guaranteed DC current gain (h_FE) range for BC847BLT3 at typical operating conditions?

The BC847BLT3 is binned to the "B" gain group, guaranteeing h_FE = 200–450 when tested at I_C = 2.0 mA and V_CE = 5.0 V. This range is verified per production lot and documented in the Electrical Characteristics table of the official datasheet (Rev. 10, page 2). Gain remains stable across −55 °C to +125 °C junction temperature, with typical variation <±15% over that range.

Can BC847BLT3 replace BC847ALT3 in existing designs?

No - BC847BLT3 and BC847ALT3 differ in guaranteed h_FE: "A" grade specifies 110–220, while "B" grade is 200–450. Substituting BC847BLT3 for BC847ALT3 may cause overdrive in base-biased circuits or unintended saturation in linear amplifiers. Always verify bias point stability and thermal margin if swapping gain bins; no pinout or package change is needed, but electrical validation is mandatory.

What is the thermal resistance (R_JA) of BC847BLT3 on a standard FR-5 PCB?

The BC847BLT3 exhibits a junction-to-ambient thermal resistance (R_JA) of 556 °C/W when mounted on a 1.0 × 0.75 × 0.062 inch FR-5 board per Note 1 in the datasheet. This value assumes no added copper pour; adding ≥15 mm² of 1-oz copper connected to the emitter pad reduces R_JA by ~20%. Derating is required above 25 °C ambient: power dissipation must decrease by 1.8 mW per °C rise.