1SMB5946H Zener Diode Equivalent & Substitute Parts

Part Overview

The 1SMB5946H is a 75 V, 3 W surface mount zener diode manufactured by Taiwan Semiconductor Corporation in DO-214AA (SMB) packaging. This component is classified as an active product with AEC-Q101 automotive qualification and ROHS3 compliance. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and supply chain continuity for applications requiring 75 V zener diode functionality in surface mount configurations.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	75	V
Tolerance	±5	%
Power - Maximum	3	W
Impedance (Maximum)	140	Ohms
Current - Reverse Leakage @ Vr	1	µA @ 56 V
Operating Temperature Range	-55 to 150	°C
Package / Case	DO-214AA, SMB	—
Mounting Type	Surface Mount	—
Grade	Automotive	—
Qualification	AEC-Q101	—

Substitute Part Grouping Explanation

Substitute parts for the 1SMB5946H are identified based on the following critical parameters that determine functional equivalence:

Primary Equivalence Criteria:

Voltage - Zener (Nominal): 75 V
Tolerance: ±5%
Package / Case: DO-214AA, SMB
Mounting Type: Surface Mount
Automotive Grade and AEC-Q101 Qualification

Substitute Categories:

Upgrade Equivalent (Direct Replacement): SZ1SMB5946BT3G by onsemi maintains identical zener voltage (75 V), tolerance (±5%), power rating (3 W), impedance (140 Ohms), and reverse leakage characteristics (1 µA @ 56 V). This part is qualified to the same AEC-Q101 standard and operates across an extended temperature range (-65°C to 150°C). The SMB package designation confirms mechanical and electrical compatibility.

Similar Substitute (Higher Power Rating): SMBJ5374B-TP by Micro Commercial Co shares the same zener voltage (75 V), tolerance (±5%), and SMB package configuration. This part features an elevated power rating of 5 W (compared to 3 W) and reduced impedance of 45 Ohms (compared to 140 Ohms). The higher power dissipation capability and lower impedance represent performance enhancements suitable for applications requiring greater thermal headroom or lower dynamic impedance characteristics.

Parameter Comparison

Parameter	1SMB5946H (Main)	SZ1SMB5946BT3G (Upgrade)	SMBJ5374B-TP (Similar)
Manufacturer	Taiwan Semiconductor Corporation	onsemi	Micro Commercial Co
Voltage - Zener (Nominal)	75 V	75 V	75 V
Tolerance	±5%	±5%	±5%
Power - Maximum	3 W	3 W	5 W
Impedance (Maximum)	140 Ohms	140 Ohms	45 Ohms
Current - Reverse Leakage @ Vr	1 µA @ 56 V	1 µA @ 56 V	500 nA @ 56 V
Operating Temperature Range	-55°C to 150°C	-65°C to 150°C	-55°C to 150°C
Package / Case	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Grade	Automotive	Automotive	—
Qualification	AEC-Q101	AEC-Q101	—
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

SZ1SMB5946BT3G (onsemi): This part is recommended as a direct upgrade equivalent for applications requiring identical electrical performance with enhanced reliability margins. The extended lower operating temperature limit (-65°C versus -55°C) provides additional thermal headroom for extreme environment applications. Both the main part and this substitute carry AEC-Q101 automotive qualification and ROHS3 compliance, ensuring regulatory and quality standard alignment. Selection of this part introduces no design modifications and maintains full functional equivalence.

SMBJ5374B-TP (Micro Commercial Co): This part is suitable for applications where increased power dissipation capability (5 W versus 3 W) or reduced dynamic impedance (45 Ohms versus 140 Ohms) provides circuit performance benefits. The lower impedance characteristic results in improved voltage regulation and reduced transient response time. However, this part does not carry explicit automotive grade or AEC-Q101 qualification designation. Selection of this substitute requires verification that application requirements do not mandate automotive qualification. The identical zener voltage, tolerance, and SMB package ensure mechanical and primary electrical compatibility.

Frequently Asked Questions (FAQ)

Q: Can SZ1SMB5946BT3G be used as a direct replacement for 1SMB5946H?

A: Yes. SZ1SMB5946BT3G maintains identical zener voltage (75 V), tolerance (±5%), power rating (3 W), impedance (140 Ohms), and reverse leakage characteristics. Both parts are AEC-Q101 qualified and ROHS3 compliant. No circuit modifications are required.

Q: What is the primary difference between 1SMB5946H and SMBJ5374B-TP?

A: Both parts share identical zener voltage (75 V) and tolerance (±5%). SMBJ5374B-TP features higher power rating (5 W versus 3 W) and lower impedance (45 Ohms versus 140 Ohms). The 1SMB5946H carries AEC-Q101 automotive qualification; SMBJ5374B-TP does not.

Q: Are all substitute parts available in the same DO-214AA (SMB) package?

A: Yes. All listed parts utilize DO-214AA (SMB) surface mount packaging, ensuring identical footprint and mounting compatibility.

Q: Which substitute part is appropriate for automotive applications?

A: SZ1SMB5946BT3G carries AEC-Q101 automotive qualification matching the main part. SMBJ5374B-TP does not carry explicit automotive qualification designation.

Q: Can SMBJ5374B-TP be used in place of 1SMB5946H in all applications?

A: SMBJ5374B-TP is electrically compatible for zener voltage and tolerance specifications. However, the higher power rating and lower impedance represent performance changes. Applications requiring automotive qualification (AEC-Q101) must use 1SMB5946H or SZ1SMB5946BT3G.

Q: What does the ±5% tolerance specification mean?

A: The zener voltage will fall within the range of 71.25 V to 78.75 V (±5% of 75 V nominal). All listed parts maintain this tolerance specification.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed parts carry ROHS3 compliance designation, meeting environmental and regulatory requirements.

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