BD538K Equivalent & Substitute Parts

Part Overview

The BD538K is an obsolete PNP bipolar junction transistor manufactured by onsemi, rated for 80 V collector-emitter breakdown voltage and 8 A maximum collector current in a TO-220-3 through-hole package. The device delivers 50 W maximum power dissipation with a 12 MHz transition frequency, suitable for general-purpose switching and amplification applications.

Due to its obsolete product status, locating original BD538K components presents supply chain challenges. Equivalent and substitute parts listed herein maintain electrical and mechanical compatibility within specified parameter ranges, enabling direct replacement in circuit designs without layout modifications.

Key Parameters

Parameter	BD538K Value	Unit
Transistor Type	PNP	—
Voltage - Collector Emitter Breakdown (Max)	80	V
Current - Collector (Ic) (Max)	8	A
Power - Max	50	W
Frequency - Transition	12	MHz
Package / Case	TO-220-3	—
Mounting Type	Through Hole	—
Operating Temperature (Max)	150	°C (TJ)

Substitute Part Grouping Explanation

Substitution eligibility for the BD538K is determined by the following criteria:

Mandatory Compatibility Parameters:

Transistor Type: PNP (all substitutes must be PNP)
Voltage - Collector Emitter Breakdown (Max): 80 V (minimum requirement)
Package / Case: TO-220-3 (mechanical and thermal interface requirement)
Mounting Type: Through Hole (PCB assembly compatibility)

Performance Parameters (Application-Dependent):

Current - Collector (Ic) (Max): Substitute must equal or exceed 8 A
Power - Max: Substitute must equal or exceed 50 W
Frequency - Transition: Substitute must equal or exceed 12 MHz

The three substitute parts listed below satisfy all mandatory compatibility parameters. Performance parameter variations are noted to enable selection based on specific application requirements.

Parameter Comparison

Parameter	BD538K	D45H11G	D45VH10G	TIP32BG	Unit
Transistor Type	PNP	PNP	PNP	PNP	—
Voltage - Collector Emitter Breakdown (Max)	80	80	80	80	V
Current - Collector (Ic) (Max)	8	10	15	3	A
Power - Max	50	2	83	2	W
Frequency - Transition	12	40	50	3	MHz
Package / Case	TO-220-3	TO-220-3	TO-220-3	TO-220-3	—
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	—
Operating Temperature (Max)	150	150	150	150	°C (TJ)
Product Status	Obsolete	Active	Active	Active	—

Engineering Selection Recommendations

D45H11G (onsemi)

The D45H11G is an active product with higher collector current rating (10 A) and superior transition frequency (40 MHz) compared to the BD538K. However, maximum power dissipation is reduced to 2 W, limiting applications requiring sustained high-power operation. This substitute is suitable for switching applications where current capacity and frequency response are prioritized over power handling. RoHS3 compliance and active product status ensure long-term availability.

D45VH10G (onsemi)

The D45VH10G is an active product offering the highest collector current (15 A) and power dissipation (83 W) among available substitutes, with transition frequency of 50 MHz. This part provides superior performance across all critical parameters and is recommended for applications requiring maximum thermal and current capacity. RoHS3 compliance and active product status support sustained supply chain access.

TIP32BG (onsemi)

The TIP32BG is an active product with reduced collector current (3 A) and power dissipation (2 W) relative to the BD538K, with transition frequency of 3 MHz. This substitute is suitable only for low-power switching applications where the BD538K's performance specifications exceed circuit requirements. RoHS3 compliance and active product status ensure availability. This part is not recommended for applications requiring the full 8 A current or 50 W power capability of the original BD538K.

Frequently Asked Questions (FAQ)

Q: Can the D45H11G directly replace the BD538K in all applications?

A: The D45H11G maintains electrical compatibility (80 V breakdown, PNP type, TO-220-3 package) and exceeds current requirements (10 A vs. 8 A). However, maximum power dissipation is reduced from 50 W to 2 W. Direct replacement is valid only for applications where sustained power dissipation does not exceed 2 W.

Q: What is the primary limitation of the TIP32BG as a BD538K substitute?

A: The TIP32BG is rated for only 3 A maximum collector current and 2 W power dissipation, both significantly below the BD538K specifications of 8 A and 50 W. This part is unsuitable for applications requiring the full performance envelope of the original device.

Q: Why is the D45VH10G recommended as the preferred substitute?

A: The D45VH10G exceeds all BD538K performance parameters: 15 A collector current (vs. 8 A), 83 W power dissipation (vs. 50 W), and 50 MHz transition frequency (vs. 12 MHz). It maintains identical voltage rating (80 V) and package format (TO-220-3). Active product status and RoHS3 compliance ensure long-term supply availability.

Q: Are all substitute parts available in the same TO-220-3 package?

A: Yes. All three substitute parts (D45H11G, D45VH10G, TIP32BG) are packaged in TO-220-3 format with through-hole mounting, enabling direct PCB replacement without layout modification.

Q: What compliance certifications apply to the substitute parts?

A: D45H11G, D45VH10G, and TIP32BG are all RoHS3 compliant and REACH unaffected. All parts carry EAR99 export classification. These certifications match or exceed the regulatory status of the obsolete BD538K.

Q: Can the BD538K be used interchangeably with these substitutes in reverse?

A: No. The BD538K is obsolete and no longer manufactured. Substitution is a one-way replacement path from the obsolete BD538K to active alternatives. The BD538K cannot serve as a substitute for active parts.

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