1SMB5944 Equivalent & Substitute Parts

Part Overview

The 1SMB5944 is an active surface mount Zener diode rated at 62 V nominal voltage with 3 W maximum power dissipation in DO-214AA (SMB) package. Manufactured by Taiwan Semiconductor Corporation, this component is RoHS3 compliant and suitable for voltage regulation and protection applications in electronic circuits. Substitute parts are identified based on matching or compatible electrical characteristics and mechanical packaging specifications to ensure functional equivalence in circuit applications.

Substiute Parts

1SMB5944

Taiwan Semiconductor CorporationIn Stock: 7571SMB5944 Datasheet

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1SMB5944BT3G

onsemiIn Stock: 152421SMB5944BT3G Datasheet

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1SMB5945BT3G

onsemiIn Stock: 209251SMB5945BT3G Datasheet

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SMBJ5371B-TP

Micro Commercial CoIn Stock: 17580SMBJ5371B-TP Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 1SMB5944 are classified based on electrical parameter compatibility and mechanical packaging equivalence. The primary substitution criteria are:

Direct Electrical Equivalents: Parts with identical nominal Zener voltage (62 V), tolerance (±5%), maximum power rating (3 W), and impedance (100 Ohms) are classified as direct substitutes. These parts maintain functional equivalence across voltage regulation and protection applications.

Similar Voltage Rating Parts: Parts with nominal Zener voltages within the application tolerance band but differing power ratings or impedance characteristics are classified as similar alternatives. These require circuit-level evaluation for suitability.

Package Compatibility: All substitute parts maintain DO-214AA (SMB) surface mount packaging, ensuring mechanical and thermal compatibility with existing PCB layouts and assembly processes.

Compliance Alignment: All substitute parts maintain RoHS3 compliance, MSL Level 1, and REACH unaffected status, ensuring regulatory and environmental compatibility.

Parameter Comparison

Engineering Selection Recommendations

1SMB5944BT3G (onsemi): This part is a direct electrical equivalent to the 1SMB5944, matching all critical parameters including 62 V nominal voltage, 3 W power rating, and 100 Ohms impedance. The extended operating temperature range (-65 to 150°C versus -55 to 150°C) provides additional thermal margin. This part is RoHS3 compliant and MSL Level 1, suitable for direct substitution in existing designs.

1SMB5945BT3G (onsemi): This part differs in nominal Zener voltage (68 V versus 62 V) and impedance (120 Ohms versus 100 Ohms). While maintaining 3 W power rating and surface mount packaging, the higher voltage rating and impedance characteristics require circuit-level verification for voltage regulation and transient response performance.

SMBJ5371B-TP (Micro Commercial Co): This part provides a higher power rating (5 W versus 3 W) with a lower nominal voltage (60 V versus 62 V) and significantly lower impedance (40 Ohms versus 100 Ohms). The enhanced power dissipation capability and improved impedance characteristics support applications requiring higher thermal performance. Circuit validation is required to confirm voltage regulation accuracy within the 60 V specification.

All substitute parts maintain RoHS3 compliance, MSL Level 1 rating, and DO-214AA (SMB) packaging compatibility with the original 1SMB5944 design.

Frequently Asked Questions (FAQ)

Q: Can the 1SMB5944BT3G replace the 1SMB5944 in all applications?

A: Yes. The 1SMB5944BT3G is a direct electrical equivalent with identical nominal voltage (62 V), power rating (3 W), tolerance (±5%), and impedance (100 Ohms). Both parts use DO-214AA (SMB) packaging and maintain RoHS3 compliance. The extended temperature range of the onsemi part provides additional operational margin.

Q: What is the primary difference between the 1SMB5944 and 1SMB5945BT3G?

A: The 1SMB5945BT3G has a higher nominal Zener voltage of 68 V compared to 62 V in the 1SMB5944. Additionally, the impedance is 120 Ohms versus 100 Ohms. Both maintain 3 W power rating and ±5% tolerance. The voltage difference affects voltage regulation setpoints and transient response characteristics.

Q: Why does the SMBJ5371B-TP have a 5 W power rating instead of 3 W?

A: The SMBJ5371B-TP is designed for applications requiring higher power dissipation capability. The 5 W rating allows sustained operation at higher current levels. However, the nominal voltage is 60 V (versus 62 V) and impedance is 40 Ohms (versus 100 Ohms), requiring circuit validation for voltage regulation accuracy.

Q: Are all substitute parts compatible with the original PCB layout?

A: Yes. All substitute parts use DO-214AA (SMB) surface mount packaging, ensuring mechanical and thermal compatibility with existing PCB designs. No layout modifications are required for package accommodation.

Q: What compliance certifications apply to all listed parts?

A: All parts are RoHS3 compliant, MSL Level 1 (Unlimited moisture sensitivity), REACH unaffected, and classified under ECCN EAR99. These certifications ensure regulatory and environmental compatibility across all substitute options.

Q: Can the SMBJ5371B-TP be used in place of the 1SMB5944 for voltage regulation?

A: The SMBJ5371B-TP has a nominal voltage of 60 V versus 62 V in the 1SMB5944. The 2 V difference and significantly lower impedance (40 Ohms versus 100 Ohms) affect voltage regulation performance. Circuit-level evaluation is required to confirm suitability for the specific voltage regulation requirement.

Q: What is the operating temperature range difference between parts?

A: The 1SMB5944 operates from -55 to 150°C. The onsemi parts (1SMB5944BT3G and 1SMB5945BT3G) extend the lower temperature limit to -65°C, providing 10°C additional margin for cold environment applications. The SMBJ5371B-TP maintains the -55 to 150°C range.