1SMB5949 Zener Diode Equivalent & Substitute Parts

Part Overview

The 1SMB5949 is an active-status surface mount zener diode rated for 100 V nominal zener voltage and 3 W maximum power dissipation in a DO-214AA (SMB) package. This component is manufactured by Taiwan Semiconductor Corporation and is RoHS3 compliant with unlimited moisture sensitivity rating. Substitute parts are identified when equivalent electrical specifications and mechanical compatibility allow direct replacement in circuit applications, or when enhanced performance characteristics justify selection as an upgrade option.

Substiute Parts

1SMB5949

Taiwan Semiconductor CorporationIn Stock: 10351SMB5949 Datasheet

Current PartRFQ

1SMB5949BT3G

onsemiIn Stock: 509491SMB5949BT3G Datasheet

UpgradeRFQ

SMBJ5378B-TP

Micro Commercial CoIn Stock: 5663SMBJ5378B-TP Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 1SMB5949 are classified into two categories based on electrical and mechanical compatibility:

Direct Equivalent (Upgrade): The 1SMB5949BT3G manufactured by onsemi maintains identical electrical specifications including 100 V zener voltage, ±5% tolerance, 3 W power rating, 250 Ohms maximum impedance, and 1 µA reverse leakage current. This part is packaged in SMB format with equivalent mechanical compatibility. The extended operating temperature range (-65°C to 150°C versus -55°C to 150°C) provides enhanced low-temperature performance. Both parts share RoHS3 compliance and unlimited MSL rating.

Similar Performance Alternative: The SMBJ5378B-TP manufactured by Micro Commercial Co maintains the 100 V zener voltage and ±5% tolerance specifications. This part features enhanced power dissipation capability at 5 W (versus 3 W) and reduced impedance at 90 Ohms (versus 250 Ohms maximum). The reverse leakage current is lower at 500 nA @ 76 V. This part is suitable for applications requiring higher power handling or lower dynamic impedance while maintaining the same zener voltage specification and SMB package format.

Parameter Comparison

Engineering Selection Recommendations

1SMB5949BT3G Selection: This onsemi part is selected as a direct equivalent upgrade when the 1SMB5949 is unavailable or when extended low-temperature operation to -65°C is required. Electrical performance is identical across all critical zener specifications. Both parts maintain RoHS3 compliance and unlimited moisture sensitivity rating. The SMB package format ensures mechanical compatibility with existing PCB layouts designed for the 1SMB5949.

SMBJ5378B-TP Selection: This Micro Commercial Co part is selected when circuit design permits higher power dissipation capability (5 W versus 3 W) or when lower dynamic impedance (90 Ohms versus 250 Ohms) provides circuit performance benefits. The 100 V zener voltage and ±5% tolerance remain identical to the main part. Lower reverse leakage current (500 nA) may benefit precision applications. RoHS3 compliance and unlimited MSL rating are maintained. The SMB package format is mechanically compatible.

All three parts are active-status components with current manufacturing support and established supply chains.

Frequently Asked Questions (FAQ)

Q: Can the 1SMB5949BT3G directly replace the 1SMB5949 in existing designs?

A: Yes. The 1SMB5949BT3G maintains identical zener voltage (100 V), tolerance (±5%), power rating (3 W), impedance (250 Ohms maximum), and reverse leakage current (1 µA @ 76 V) specifications. Both parts use the DO-214AA (SMB) package format. The extended operating temperature range of the onsemi part (-65°C to 150°C) provides additional low-temperature capability without affecting circuit compatibility.

Q: What are the key differences between the 1SMB5949 and SMBJ5378B-TP?

A: Both parts maintain the 100 V zener voltage and ±5% tolerance. The SMBJ5378B-TP provides higher power dissipation at 5 W (versus 3 W) and lower dynamic impedance at 90 Ohms (versus 250 Ohms maximum). Reverse leakage current is lower at 500 nA @ 76 V. These differences make the SMBJ5378B-TP suitable for applications requiring enhanced power handling or lower impedance characteristics while maintaining the same zener voltage specification.

Q: Are all three parts mechanically compatible with the same PCB footprint?

A: Yes. All three parts use the DO-214AA (SMB) surface mount package format, ensuring mechanical and footprint compatibility across existing circuit board designs.

Q: Do all substitute parts meet the same compliance standards as the 1SMB5949?

A: Yes. The 1SMB5949BT3G and SMBJ5378B-TP are both RoHS3 compliant with unlimited moisture sensitivity level (MSL 1) ratings, matching the compliance profile of the main part.

Q: Which substitute part should be selected for low-temperature applications below -55°C?

A: The 1SMB5949BT3G is specified for operation down to -65°C, extending the low-temperature operating range by 10°C compared to the 1SMB5949 and SMBJ5378B-TP, both rated to -55°C minimum.

Q: Can the SMBJ5378B-TP be used in applications designed for the 1SMB5949 if thermal management is adequate?

A: The SMBJ5378B-TP maintains the 100 V zener voltage and ±5% tolerance required for functional compatibility. The higher power rating (5 W) and lower impedance (90 Ohms) represent performance enhancements. Circuit design must accommodate the different impedance characteristic, which affects transient response and voltage regulation behavior.