onsemi 2N4918G

Overview

2N4918G from onsemi is a medium-power plastic PNP silicon transistor designed for switching and linear amplifier applications in driver-stage circuits. It delivers V_CEO = 40 V, I_C = 1.0 A (JEDEC-compliant), P_D = 30 W at T_C = 25°C, V_CE(sat) ≤ 0.6 V at I_C = 1.0 A/ I_B = 0.1 A, and operates across −65°C to +150°C junction temperature range - used in industrial relay drivers and DC motor control stages.

For engineers reviewing the 2N4918G datasheet, pinout, applications, or equivalent options, this page provides verified package mapping (TO-225, Style 1), confirmed PNP polarity and thermal resistance (R_θJC = 4.16°C/W), JEDEC-compliant gain spec at 1.0 A, and direct alternatives with validated voltage/current trade-offs.

Technical Context

This PNP bipolar junction transistor uses epitaxial-base construction for stable high-current gain (h_FE ≥ 10 at I_C = 1.0 A) and low saturation voltage. Its safe operating area (SOA) is defined up to second-breakdown limits at 5 ms pulse width and thermally constrained at DC, with normalized transient thermal response documented for pulsed power design.

The device features complementary pairing with NPN types 2N4921–2N4923 and supports robust switching via specified t_r, t_f, t_s′ timing parameters under I_C/I_B = 10–20 conditions. Base-emitter on-voltage (V_BE(on) ≤ 1.3 V) and cutoff leakage (I_CEO ≤ 0.5 mA at V_CE = 20 V) are characterized across −55°C to +150°C.

Key Specifications

Pinout & Package

2N4918G is housed in a TO-225 (Case 077, Style 1) plastic package with 4-pin configuration (pins 1–4), where pins 2 and 4 are internally connected to the collector terminal. The backside metal tab is electrically connected to the collector and serves as primary thermal path.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP power transistor applications.

Compared with MJD44H11G and BD140, the 2N4918G offers optimized thermal coupling via TO-225 collector-tab mounting and JEDEC-guaranteed h_FE at 1.0 A - making it preferable for through-hole driver stages where mechanical robustness and predictable gain at full rated current are prioritized.

Availability

2N4918G is available at Aetrix Electronics and suitable for industrial relay drivers, DC motor direction control, and linear voltage regulator pass elements requiring stable component supply and long-term obsolescence management.

Supply support for 2N4918G 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 consumer markets.

The 2N4918G belongs to the legacy 2N4918–2N4920 series of medium-power PNP transistors engineered for rugged driver and amplifier roles in industrial control hardware where reliability under thermal and electrical stress is critical.

FAQ

What is the maximum continuous collector current rating for the 2N4918G?

The 2N4918G has a JEDEC-specified maximum continuous collector current (I_C) of 1.0 Adc at T_C = 25°C. While its physical construction supports up to 3.0 A for short pulses (per SOA curve Fig.5), sustained operation beyond 1.0 A requires strict thermal management and derating per the 0.24 W/°C curve. The 1.0 A rating ensures guaranteed h_FE, V_CE(sat), and reliability under standard test conditions.

Is the 2N4918G pin-compatible with other transistors in the 2N4918–2N4920 series?

Yes, the 2N4918G shares identical TO-225 (Style 1) pinout - Pin 1 = Emitter, Pins 2 & 4 = Collector, Pin 3 = Base - with all variants in the 2N4918–2N4920 series. However, V_CEO, V_CBO, and SOA differ: 2N4918G is rated for 40 V, while 2N4919G and 2N4920G support 60 V and 80 V respectively. Substituting higher-voltage variants requires verifying circuit voltage margins.

Does the "G" suffix in 2N4918G indicate RoHS compliance?

Yes, the "G" suffix on 2N4918G explicitly denotes a Pb-Free (RoHS-compliant) package per onsemi's marking convention. This includes lead-free terminations and halogen-free molding compound, qualified for reflow soldering per J-STD-020. The device meets EU RoHS Directive 2011/65/EU and related regional environmental regulations.

Can the 2N4918G be used in switching applications above 10 kHz?

The 2N4918G exhibits measured switching times including t_r < 15 ns, t_f ≈ 0.07–0.7 μs (Fig.7), and t_s′ ≈ 0.05–0.5 μs (Fig.6) under I_C/I_B = 10–20, supporting operation up to ~100 kHz in well-designed hard-switched circuits. However, f_T = 3.0 MHz indicates limited small-signal gain at high frequencies; for >50 kHz PWM, verify gate/base drive strength and layout parasitics to avoid excessive switching losses.

What is the thermal resistance from junction to case (R_θJC) for the 2N4918G?

The 2N4918G has a maximum junction-to-case thermal resistance (R_θJC) of 4.16°C/W, measured from die junction to the collector metal tab. This value assumes optimal mounting with thermal compound between the tab and heatsink. Without compound, R_θJC degrades significantly; actual system R_θJA depends on heatsink size, airflow, and PCB copper area.