onsemi BC237G

Overview

BC237G from onsemi is an NPN silicon general-purpose amplifier transistor in TO-92 package, rated for V_CEO = 45 V, I_C = 100 mA, P_D = 350 mW at T_A = 25°C, with h_FE = 120–380 (at I_C = 10 mA, V_CE = 5 V), and f_T = 150 MHz - used in low-noise audio preamplifier stages and signal buffering circuits.

For engineers reviewing the BC237G datasheet, pinout, applications, or equivalent options, key selection considerations include its Pb-free TO-92 construction, guaranteed h_FE binning (B-grade), low V_CE(sat) of 0.2 V at I_C/I_B = 10, and thermal resistance R_JA = 357 °C/W for ambient-limited linear operation.

Technical Context

The BC237G operates as a medium-speed, low-power NPN bipolar junction transistor optimized for linear amplification rather than switching. Its design emphasizes stable DC current gain across collector currents from 0.2 mA to 100 mA and low noise figure (NF = 4.0 dB at I_C = 0.2 mA, f = 1 kHz), making it suitable for analog front-end signal conditioning.

It features a maximum V_CEO of 45 V and V_CES of 50 V, enabling use in 24 V rail systems with margin. The device's C_obo = 4.5 pF and C_ibo = 8.0 pF support stable high-frequency performance up to its f_T = 150 MHz, while its base spreading resistance remains below 170 Ω across operating current range.

Key Specifications

Pinout & Package

BC237G is housed in a Pb-free TO-92 (Case 29-11, Style 17) plastic package with standard lead configuration and 350 mW power rating at 25°C ambient.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN amplifier transistor applications.

Compared with BC237G, BC547B offers higher bandwidth and power, while PN2222A provides greater dissipation headroom but less consistent h_FE and RoHS compliance unless specified as "G" suffix - all three share TO-92 footprint and basic biasing methodology.

Availability

BC237G is available at Aetrix Electronics and suitable for audio preamplifiers, level-shifting interfaces, and bias current sources requiring stable component supply, RoHS-compliant packaging, and verified h_FE binning.

Supply support for BC237G 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 delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The BC237G belongs to onsemi's legacy general-purpose bipolar transistor product line, designed specifically for cost-sensitive, high-reliability linear amplification and switching in consumer and industrial electronics.

FAQ

What is the maximum collector current rating for BC237G?

The BC237G has a maximum continuous collector current (I_C) rating of 100 mA at T_A = 25°C. Derating applies above 25°C ambient - at 70°C, usable I_C drops to approximately 80 mA based on its 2.8 mW/°C thermal derating coefficient. This rating assumes proper PCB copper area for heat dissipation and excludes pulsed operation limits.

Is BC237G RoHS-compliant and what does the "G" suffix indicate?

Yes, BC237G is RoHS-compliant. The "G" suffix explicitly denotes a Pb-free (lead-free) version per JEDEC J-STD-020, using matte tin lead finish and halogen-free molding compound. This distinguishes it from non-G variants like BC237B, which may contain lead in terminations or packaging materials unless otherwise specified.

What h_FE range is guaranteed for BC237G?

The BC237G is the "B"-grade variant, guaranteeing h_FE = 120–200 when measured at I_C = 10 mA and V_CE = 5 V, per onsemi's BC237/D datasheet Rev. 4. This binning ensures tighter DC gain consistency than the standard BC237 (h_FE = 110–460) and supports robust bias network design without post-manufacture sorting.

Can BC237G be used in switching applications?

Yes, BC237G can be used in low-speed switching applications, with V_CE(sat) ≤ 0.2 V at I_C/I_B = 10 and t_on/t_off < 1 μs. However, its f_T = 150 MHz and moderate C_obo/C_ibo make it less optimal than dedicated switching transistors (e.g., MMBT2222A) for >100 kHz PWM or digital logic interfacing where faster edges are critical.

What is the thermal resistance junction-to-ambient (R_JA) for BC237G?

The BC237G has a specified R_JA of 357 °C/W under standard JEDEC test conditions (single-layer PCB, 1 in² copper pad). In real-world layouts with 2 oz copper and thermal vias, R_JA typically improves to 200–250 °C/W. This value determines safe power dissipation: at 70°C ambient, max P_D ≈ 225 mW before exceeding 150°C junction temperature.