onsemi BC558BRLG

Overview

BC558BRLG from onsemi is a PNP silicon small-signal amplifier transistor in TO-92 package, rated for −30 V V_CEO, −30 V V_CBO, −5.0 V V_EBO, −100 mA I_C, and 360 MHz f_T. It delivers h_FE = 220–460 at I_C = −2.0 mA and is used in low-noise audio preamplifiers, discrete logic inverters, and biasing networks in industrial sensor signal conditioning.

For engineers reviewing the BC558BRLG datasheet, pinout, applications, or equivalent options, key selection criteria include its PNP polarity, TO-92 mechanical compatibility, guaranteed h_FE range, V_CEO rating for 24 V rail operation, and 2.0 nA I_CES leakage at −20 V - critical for battery-powered analog front-ends and precision current mirrors.

Technical Context

The BC558BRLG operates as a general-purpose PNP bipolar junction transistor with fixed-emitter bias topology support. Its DC current gain (h_FE) is specified across three test conditions: −120–300 at I_C = −10 mA, −220–460 at I_C = −2.0 mA, and −260–500 at I_C = −100 mA - enabling stable operation in both linear amplification and saturated switching modes.

Small-signal performance includes f_T = 360 MHz at I_C = −10 mA, C_ob = 3.0–6.0 pF at V_CB = −10 V, and NF = 2.0 dB at I_C = −0.2 mA - confirming suitability for audio-frequency amplification and low-distortion active filters where phase margin and noise floor matter.

Key Specifications

Pinout & Package

BC558BRLG uses TO-92 (Case 29, Style 17) package with bent leads, Pb-free finish, and standard 2.54 mm lead pitch. Dimensions: 4.45–5.20 mm height, 4.32–5.33 mm width, 3.18–4.19 mm thickness.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP small-signal amplifier applications.

Compared with BC558BRLG, BC557BRL1G offers +15 V higher V_CEO but trades 40 MHz f_T and narrower h_FE range; BC556BRL1G adds +35 V margin but sacrifices 80 MHz bandwidth and 140-point h_FE span - making BC558BRLG optimal for 24 V systems demanding balanced gain, speed, and noise.

Availability

BC558BRLG is available at Aetrix Electronics and suitable for audio preamplifiers, discrete logic level shifters, and sensor bias networks requiring stable component supply, consistent h_FE binning, and RoHS-compliant TO-92 packaging.

Supply support for BC558BRLG 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, sensors, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The BC558BRLG belongs to the BC556/557/558 family of general-purpose PNP transistors designed for cost-sensitive, high-reliability linear and switching applications in consumer, industrial, and communications equipment.

FAQ

What is the maximum collector-emitter voltage rating for BC558BRLG?

The BC558BRLG has a guaranteed V_CEO rating of −30 Vdc, meaning it can safely block up to 30 V between collector and emitter with base open. This rating is validated per JEDEC JESD78 stress testing and applies across the full −55°C to +150°C junction temperature range. Exceeding this voltage risks avalanche breakdown and permanent device failure. The BC558BRLG must not be used in circuits where transient spikes exceed −30 V without external clamping.

Does BC558BRLG have a Pb-free package?

Yes, BC558BRLG is manufactured in a Pb-free TO-92 package compliant with RoHS Directive 2011/65/EU and JEDEC J-STD-020 moisture sensitivity level (MSL) 1. The "G" suffix in the part number explicitly denotes Pb-free construction, and the device supports standard lead-free reflow profiles with peak temperatures up to 260°C. No lead-based solder is used in die attach, wire bonding, or lead frame plating.

What is the h_FE range for BC558BRLG at I_C = −2.0 mA?

The BC558BRLG is binned as a "B-series" device with h_FE = 220–460 when tested at I_C = −2.0 mAdc and V_CE = −5.0 Vdc at T_A = 25°C. This range is guaranteed per onsemi's production test flow and reflects actual measured values - not typical or minimum-only specifications. Designers may rely on this span for worst-case bias calculations in emitter-degenerated amplifier stages.

Can BC558BRLG replace BC557B in existing designs?

BC558BRLG is not a direct replacement for BC557B due to differences in absolute maximum ratings: BC557B has V_CEO = −45 V and V_CBO = −50 V versus BC558BRLG's −30 V ratings. While pinout and package are identical (TO-92 Style 17), substituting BC558BRLG in a −40 V application violates its V_CEO limit. It is only safe for drop-in use where operating V_CE remains ≤25 V with margin.

What is the thermal resistance junction-to-ambient for BC558BRLG?

The BC558BRLG has a maximum R_JA of 200°C/W when mounted on a standard FR4 PCB with minimal copper area. This value assumes natural convection cooling and no heatsink. Derating begins at 5.0 mW/°C above 25°C ambient, meaning usable power drops to 500 mW at 50°C ambient. For sustained 625 mW operation, board layout must include ≥1 in² of 2-oz copper pour connected to the emitter pad.