1SMB5939 Zener Diode Equivalent & Substitute Parts

Part Overview

The 1SMB5939 is a 39 V, 3 W Zener diode manufactured by Taiwan Semiconductor Corporation in the DO-214AA (SMB) surface mount package. This component is classified as an active product with full RoHS3 compliance and unlimited moisture sensitivity rating. The 1SMB5939 serves voltage regulation and transient protection applications in electronic circuits. Equivalent and substitute parts are identified based on matching electrical specifications, mechanical compatibility, and regulatory compliance to ensure functional interchangeability in circuit designs.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	39	V
Power - Maximum	3	W
Tolerance	±5	%
Impedance (Maximum)	45	Ohms
Current - Reverse Leakage @ Vr	1	µA @ 29.7 V
Operating Temperature Range	-55 to 150	°C
Package / Case	DO-214AA, SMB	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitute parts for the 1SMB5939 are qualified based on the following critical parameters:

Electrical Equivalence Criteria:

Zener voltage (Nominal): 39 V
Power dissipation rating: 3 W
Voltage tolerance: ±5%
Impedance (Maximum): 45 Ohms
Reverse leakage current: 1 µA @ 29.7 V

Mechanical Compatibility Criteria:

Package type: DO-214AA (SMB)
Mounting type: Surface Mount
Moisture sensitivity level: 1 (Unlimited)

Regulatory Compliance Criteria:

RoHS3 compliance
REACH unaffected status
ECCN classification: EAR99

All identified substitute parts meet these criteria and are therefore functionally and mechanically interchangeable with the 1SMB5939 in circuit applications.

Parameter Comparison

Parameter	1SMB5939 (TSC)	3SMBJ5939B-TP (MCC)	1SMB5939BT3G (onsemi)
Manufacturer	Taiwan Semiconductor Corporation	Micro Commercial Co	onsemi
Voltage - Zener (Nom)	39 V	39 V	39 V
Power - Max	3 W	3 W	3 W
Tolerance	±5%	±5%	±5%
Impedance (Max)	45 Ohms	45 Ohms	45 Ohms
Current - Reverse Leakage @ Vr	1 µA @ 29.7 V	1 µA @ 29.7 V	1 µA @ 29.7 V
Voltage - Forward (Vf) (Max) @ If	Not specified	1.5 V @ 200 mA	1.5 V @ 200 mA
Operating Temperature	-55°C ~ 150°C	-55°C ~ 150°C	-65°C ~ 150°C
Package / Case	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Packaging	Tape & Reel (TR)	Tape & Reel (TR)	Cut Tape (CT) & Digi-Reel®
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected
Product Status	Active	Active	Active

Engineering Selection Recommendations

All three parts—1SMB5939 (Taiwan Semiconductor Corporation), 3SMBJ5939B-TP (Micro Commercial Co), and 1SMB5939BT3G (onsemi)—are active products with full RoHS3 compliance and REACH unaffected status. Each part meets the electrical and mechanical specifications required for 39 V, 3 W Zener diode applications in the DO-214AA (SMB) package.

1SMB5939 (Taiwan Semiconductor Corporation): Primary specification baseline with standard operating temperature range of -55°C to 150°C. Suitable for general-purpose voltage regulation and transient protection circuits.

3SMBJ5939B-TP (Micro Commercial Co): Direct equivalent with identical electrical parameters and operating temperature range. Provides alternative sourcing with higher inventory availability (3587 pcs). Includes forward voltage specification (1.5 V @ 200 mA) for applications requiring this parameter.

1SMB5939BT3G (onsemi): Extended lower operating temperature limit (-65°C to 150°C) compared to the primary part. Suitable for applications requiring operation at temperatures below -55°C. Highest inventory availability (15100 pcs). Supplied in Cut Tape and Digi-Reel® packaging format.

Selection among these parts depends on sourcing availability, packaging format requirements, and operating temperature specifications for the target application.

Frequently Asked Questions (FAQ)

Q: Can the 3SMBJ5939B-TP be used as a direct replacement for the 1SMB5939?

A: Yes. Both parts share identical Zener voltage (39 V), power rating (3 W), tolerance (±5%), impedance (45 Ohms), reverse leakage current (1 µA @ 29.7 V), operating temperature range (-55°C to 150°C), and package type (DO-214AA, SMB). Both are RoHS3 compliant with unlimited moisture sensitivity rating.

Q: What is the difference between the 1SMB5939BT3G and the other two parts?

A: The 1SMB5939BT3G has an extended lower operating temperature limit of -65°C compared to -55°C for the other parts. All other electrical and mechanical specifications are identical. The packaging format differs (Cut Tape & Digi-Reel® versus Tape & Reel).

Q: Are there any compatibility issues with different packaging formats?

A: No. The packaging format (Tape & Reel versus Cut Tape & Digi-Reel®) affects handling and storage logistics but does not impact electrical or mechanical compatibility. All parts use the same DO-214AA (SMB) package for circuit board mounting.

Q: Which part should be selected for low-temperature applications?

A: The 1SMB5939BT3G (onsemi) is specified for operation down to -65°C, making it suitable for applications requiring operation below -55°C. The other two parts are rated to -55°C minimum.

Q: Are all three parts RoHS3 compliant?

A: Yes. All three parts—1SMB5939, 3SMBJ5939B-TP, and 1SMB5939BT3G—are RoHS3 compliant with REACH unaffected status and ECCN classification EAR99.

Q: Can these parts be used interchangeably in existing circuit designs?

A: Yes. All three parts meet the same electrical specifications (39 V Zener voltage, 3 W power rating, ±5% tolerance, 45 Ohms impedance) and use the same DO-214AA (SMB) surface mount package. They are functionally and mechanically interchangeable.

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