1SMB5955H Zener Diode Equivalent & Substitute Parts

Part Overview

The 1SMB5955H is an active-status surface mount zener diode manufactured by Taiwan Semiconductor Corporation, rated for 180 V nominal zener voltage and 3 W maximum power dissipation in a DO-214AA (SMB) package. This component is designed for voltage regulation and transient protection applications requiring high-voltage zener characteristics. Substitute parts are identified based on matching or exceeding electrical specifications within the zener diode category, maintaining compatibility with surface mount assembly processes and automotive-grade reliability standards.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	180	V
Tolerance	±5	%
Power - Max	3	W
Impedance (Max)	900	Ohms
Current - Reverse Leakage @ Vr	1	µA @ 136.8 V
Operating Temperature Range	-55 to 150	°C
Package / Case	DO-214AA, SMB
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Grade	Automotive
Qualification	AEC-Q101

Substitute Part Grouping Explanation

Substitute parts for the 1SMB5955H are selected based on the following critical parameters that determine functional equivalence:

Primary Matching Criteria:

Voltage - Zener (Nom): 180 V nominal rating
Tolerance: ±5% specification
Package / Case: DO-214AA (SMB) surface mount package
Mounting Type: Surface mount compatibility
RoHS Status: ROHS3 Compliant
Operating Temperature Range: Minimum -55°C to 150°C coverage

Secondary Compatibility Factors:

Power - Max: Equal or greater than 3 W
Impedance (Max): Zzt value within acceptable range for circuit performance
Current - Reverse Leakage: Specification at rated voltage
Product Status: Active status for ongoing availability

The 1SMB5955H has three identified substitute parts. Two substitutes (SMBJ5386B-TP and 1SMB5955BT3G) maintain the exact 180 V zener voltage specification. One substitute (SMBJ5385B-TP) operates at 170 V, representing a lower voltage alternative. All substitutes maintain surface mount SMB packaging and automotive-grade compliance.

Parameter Comparison

Parameter	1SMB5955H (Main)	1SMB5955BT3G	SMBJ5386B-TP	SMBJ5385B-TP
Manufacturer	Taiwan Semiconductor Corporation	onsemi	Micro Commercial Co	Micro Commercial Co
Voltage - Zener (Nom)	180 V	180 V	180 V	170 V
Tolerance	±5%	±5%	±5%	±5%
Power - Max	3 W	3 W	5 W	5 W
Impedance (Max)	900 Ohms	900 Ohms	430 Ohms	380 Ohms
Current - Reverse Leakage @ Vr	1 µA @ 136.8 V	1 µA @ 136.8 V	500 nA @ 137 V	500 nA @ 129 V
Operating Temperature Range	-55 to 150°C	-65 to 150°C	-55 to 150°C	-55 to 150°C
Package / Case	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB	DO-214AA, SMB
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Active	Active	Active	Active

Engineering Selection Recommendations

Direct Equivalent (1SMB5955BT3G): The 1SMB5955BT3G manufactured by onsemi is a direct electrical equivalent to the 1SMB5955H. Both components share identical zener voltage (180 V), tolerance (±5%), power rating (3 W), and impedance (900 Ohms) specifications. The 1SMB5955BT3G provides an extended lower operating temperature limit (-65°C versus -55°C), offering enhanced performance in cold-temperature environments. Both parts maintain ROHS3 compliance and active product status. The primary difference is packaging format: 1SMB5955H is supplied in Tape & Reel (TR), while 1SMB5955BT3G is supplied in Cut Tape (CT) & Digi-Reel format.

Higher Power Alternative (SMBJ5386B-TP): The SMBJ5386B-TP manufactured by Micro Commercial Co maintains the 180 V zener voltage specification while providing increased power dissipation capability (5 W versus 3 W). This substitute is suitable for applications requiring higher thermal headroom or greater transient energy absorption. The impedance is lower (430 Ohms versus 900 Ohms), resulting in improved voltage regulation characteristics. Reverse leakage current is reduced (500 nA versus 1 µA), indicating superior leakage performance. ROHS3 compliance and active product status are maintained.

Lower Voltage Alternative (SMBJ5385B-TP): The SMBJ5385B-TP manufactured by Micro Commercial Co operates at 170 V nominal zener voltage, representing a 10 V reduction from the 1SMB5955H specification. This substitute is applicable only in circuits where the lower voltage threshold is acceptable. The component offers 5 W power rating and reduced impedance (380 Ohms), providing superior regulation performance. Reverse leakage current is significantly lower (500 nA). ROHS3 compliance and active product status are maintained. Operating temperature range matches the main part (-55°C to 150°C).

All substitute parts maintain automotive-grade reliability through ROHS3 compliance and active product status, ensuring long-term component availability and supply chain stability.

Frequently Asked Questions (FAQ)

Q: Can 1SMB5955BT3G be used as a direct replacement for 1SMB5955H?

A: Yes. The 1SMB5955BT3G is a direct electrical equivalent with identical zener voltage (180 V), tolerance (±5%), power rating (3 W), and impedance (900 Ohms). The primary difference is packaging format (Cut Tape & Digi-Reel versus Tape & Reel). Both components are ROHS3 compliant and active status. The 1SMB5955BT3G provides extended lower temperature operation (-65°C versus -55°C).

Q: What is the difference between the 3 W and 5 W power-rated substitutes?

A: Power rating indicates maximum continuous power dissipation capability. The SMBJ5386B-TP and SMBJ5385B-TP are rated for 5 W, compared to 3 W for the 1SMB5955H. Higher power rating allows the component to dissipate greater transient energy without exceeding junction temperature limits. Selection depends on circuit power requirements and thermal design.

Q: Can SMBJ5385B-TP (170 V) be used in place of 1SMB5955H (180 V)?

A: SMBJ5385B-TP operates at 170 V nominal zener voltage, which is 10 V lower than the 1SMB5955H specification. This substitute is applicable only in circuits where the lower voltage threshold meets design requirements. Voltage-sensitive applications must evaluate circuit performance at the reduced zener voltage before substitution.

Q: Are all substitute parts automotive-grade qualified?

A: All substitute parts listed maintain ROHS3 compliance and active product status. The 1SMB5955H carries explicit AEC-Q101 automotive qualification. Substitute parts from Micro Commercial Co and onsemi maintain ROHS3 compliance. Specific automotive qualification status for substitute parts should be confirmed through manufacturer documentation if AEC-Q101 certification is a design requirement.

Q: What is the significance of impedance differences among the substitutes?

A: Impedance (Zzt) affects voltage regulation performance. Lower impedance values (SMBJ5386B-TP at 430 Ohms and SMBJ5385B-TP at 380 Ohms) provide better voltage regulation compared to the 1SMB5955H at 900 Ohms. Circuits sensitive to voltage ripple or regulation accuracy may benefit from lower impedance substitutes.

Q: Do all substitutes use the same DO-214AA (SMB) package?

A: Yes. All substitute parts use the DO-214AA (SMB) surface mount package, ensuring mechanical and electrical compatibility with existing PCB layouts and assembly processes. Packaging format (Tape & Reel versus Cut Tape) affects supply and handling but does not impact component functionality.

Q: What is the reverse leakage current significance?

A: Reverse leakage current indicates the small current flowing through the zener diode when reverse-biased below the zener voltage. Lower leakage current (500 nA in SMBJ5386B-TP and SMBJ5385B-TP versus 1 µA in 1SMB5955H) results in lower standby power consumption and improved circuit efficiency in voltage regulation applications.

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