2N4918G Equivalent & Substitute Parts

Part Overview

The 2N4918G is a PNP bipolar junction transistor manufactured by onsemi, designed for general-purpose switching and amplification applications. This device features a maximum collector current of 1 A, collector-emitter breakdown voltage of 40 V, and maximum power dissipation of 30 W in a Through Hole TO-126 package. The 2N4918G is currently in Last Time Buy status, indicating that new production has ceased and existing inventory is limited. Identification of equivalent substitute parts is necessary to ensure design continuity and long-term component availability for new designs or production requirements.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Current - Collector (Ic) (Max)	1	A
Voltage - Collector Emitter Breakdown (Max)	40	V
Vce Saturation (Max) @ Ib, Ic	600mV @ 100mA, 1A	—
DC Current Gain (hFE) (Min) @ Ic, Vce	30 @ 500mA, 1V	—
Power - Max	30	W
Frequency - Transition	3	MHz
Operating Temperature	-65 to 150	°C (TJ)
Mounting Type	Through Hole	—
Package / Case	TO-126-3	—

Substitute Part Grouping Explanation

Substitution of the 2N4918G is determined by electrical and mechanical compatibility within the following critical parameters:

Electrical Compatibility Criteria:

Transistor polarity must remain PNP
Maximum collector current (Ic) must equal or exceed 1 A
Collector-emitter breakdown voltage (VCEO) must equal or exceed 40 V
Maximum power dissipation must equal or exceed 30 W
Transition frequency must equal or exceed 3 MHz
Operating temperature range must encompass -65°C to 150°C

Mechanical Compatibility Criteria:

Package type must be TO-126-3 (Through Hole)
Pin configuration must be compatible with TO-126 footprint

The BD180G meets all substitution criteria. It provides higher voltage capability (80 V VCEO), maintains identical current and power ratings, and is housed in the same TO-126-3 package with identical pin configuration.

Parameter Comparison

Parameter	2N4918G	BD180G	Unit
Transistor Type	PNP	PNP	—
Current - Collector (Ic) (Max)	1	1	A
Voltage - Collector Emitter Breakdown (Max)	40	80	V
Vce Saturation (Max) @ Ib, Ic	600mV @ 100mA, 1A	800mV @ 100mA, 1A	—
DC Current Gain (hFE) (Min) @ Ic, Vce	30 @ 500mA, 1V	40 @ 150mA, 2V	—
Power - Max	30	30	W
Frequency - Transition	3	3	MHz
Operating Temperature	-65 to 150	-65 to 150	°C (TJ)
Mounting Type	Through Hole	Through Hole	—
Package / Case	TO-126-3	TO-126-3	—
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	—
REACH Status	REACH Unaffected	REACH Unaffected	—

Engineering Selection Recommendations

2N4918G Status Consideration: The 2N4918G is designated Last Time Buy, indicating cessation of production. For new designs or ongoing production requirements, the BD180G is the manufacturer-recommended substitute and is currently in Active product status with confirmed inventory availability.

Compliance Alignment: Both the 2N4918G and BD180G maintain identical RoHS3 compliance and REACH Unaffected status, ensuring regulatory continuity in applications subject to environmental restrictions.

Electrical Performance: The BD180G provides enhanced voltage capability (80 V versus 40 V VCEO) while maintaining identical current and power ratings. This higher voltage rating provides additional design margin in applications operating near the 2N4918G's voltage limits. The slightly elevated Vce saturation (800mV versus 600mV) and higher DC current gain (40 versus 30 hFE) represent minor performance variations that remain within typical application tolerances for general-purpose switching circuits.

Mechanical Compatibility: Identical TO-126-3 package and pin configuration enable direct footprint substitution without PCB redesign.

Frequently Asked Questions (FAQ)

Q: Can the BD180G directly replace the 2N4918G in existing designs?

A: Yes. The BD180G is electrically and mechanically compatible with the 2N4918G. Both devices share identical collector current (1 A), power dissipation (30 W), transition frequency (3 MHz), operating temperature range (-65°C to 150°C), and TO-126-3 package configuration. The BD180G's higher voltage rating (80 V versus 40 V) provides additional design margin without requiring circuit modification.

Q: What are the key differences between the 2N4918G and BD180G?

A: The primary differences are collector-emitter breakdown voltage (40 V versus 80 V), Vce saturation (600mV versus 800mV at specified conditions), and DC current gain (30 versus 40 hFE at specified conditions). The BD180G's higher voltage capability makes it suitable for applications requiring greater voltage headroom. Both devices maintain identical current, power, frequency, and temperature specifications.

Q: Are there compliance or regulatory differences between these parts?

A: No. Both the 2N4918G and BD180G are ROHS3 compliant and REACH Unaffected, ensuring identical regulatory status for applications subject to environmental restrictions.

Q: Why is the 2N4918G being discontinued?

A: The 2N4918G is in Last Time Buy status, indicating manufacturer discontinuation of production. The BD180G serves as the active replacement, offering equivalent functionality with enhanced voltage capability.

Q: Does the BD180G require any circuit modifications when substituting for the 2N4918G?

A: No circuit modifications are required. The BD180G is a direct pin-compatible replacement with identical electrical performance in the specified operating parameters. The higher voltage rating provides additional margin without affecting circuit operation.

Q: What is the TO-126-3 package configuration?

A: The TO-126-3 is a three-pin Through Hole package with standard PNP transistor pinout: Base (pin 1), Collector (pin 2), and Emitter (pin 3). Both the 2N4918G and BD180G use this identical configuration, enabling direct PCB substitution.

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