TPSMC91A Equivalent & Substitute Parts

Part Overview

The TPSMC91A is a unidirectional Zener transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for surface mount applications in the DO-214AB package. This component provides transient overvoltage protection with a 77.8V reverse standoff voltage and 125V maximum clamping voltage. The part is actively produced, AEC-Q101 qualified for automotive applications, and ROHS3 compliant. Substitute parts are identified when equivalent electrical performance and mechanical compatibility are maintained across the specified parameter ranges.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	77.8	V
Voltage - Breakdown (Min)	86.5	V
Voltage - Clamping (Max) @ Ipp	125	V
Current - Peak Pulse (10/1000µs)	12.2	A
Power - Peak Pulse	1500	W
Operating Temperature Range	-55 to 150	°C
Package / Case	DO-214AB, SMC	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution of the TPSMC91A is determined by strict equivalence across the following critical parameters:

Voltage specifications: Reverse standoff voltage of 77.8V (typical), breakdown voltage minimum of 86.5V, and clamping voltage maximum of 125V must be maintained.

Current rating: Peak pulse current must meet or exceed 12.2A at the 10/1000µs pulse condition.

Power dissipation: Peak pulse power rating of 1500W must be supported.

Package compatibility: DO-214AB surface mount package is required for mechanical and thermal compatibility.

Temperature range: Operating range of -55°C to 150°C junction temperature must be supported.

The 1.5SMC91A from Taiwan Semiconductor Corporation meets all these criteria and is identified as a direct substitute.

Parameter Comparison

Parameter	TPSMC91A (Littelfuse)	1.5SMC91A (Taiwan Semiconductor)	Match Status
Voltage - Reverse Standoff (Typ)	77.8V	77.8V	Equivalent
Voltage - Breakdown (Min)	86.5V	86.5V	Equivalent
Voltage - Clamping (Max) @ Ipp	125V	125V	Equivalent
Current - Peak Pulse (10/1000µs)	12.2A	12.6A	Substitute Exceeds
Power - Peak Pulse	1500W	1500W	Equivalent
Operating Temperature	-55°C to 150°C	-55°C to 150°C	Equivalent
Package / Case	DO-214AB, SMC	DO-214AB, SMC	Equivalent
Mounting Type	Surface Mount	Surface Mount	Equivalent
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Equivalent
Moisture Sensitivity Level	1 (Unlimited)	1 (Unlimited)	Equivalent

Engineering Selection Recommendations

Both the TPSMC91A and 1.5SMC91A are active production components with ROHS3 compliance and MSL Level 1 rating. The TPSMC91A carries AEC-Q101 automotive qualification. The 1.5SMC91A provides equivalent electrical performance with a slightly higher peak pulse current rating of 12.6A compared to the 12.2A specification of the primary part. Both components support identical voltage clamping and power dissipation characteristics. Selection between these parts should be based on availability, lead time, and application-specific automotive qualification requirements where AEC-Q101 certification is mandated.

Frequently Asked Questions (FAQ)

Q: Can the 1.5SMC91A directly replace the TPSMC91A in existing designs?

A: Yes. The 1.5SMC91A meets all electrical and mechanical specifications of the TPSMC91A. Both components share identical voltage ratings, clamping characteristics, operating temperature range, and DO-214AB package configuration. The substitute part's higher peak pulse current rating (12.6A vs 12.2A) provides additional margin without affecting circuit compatibility.

Q: Are there package differences between these parts?

A: No. Both the TPSMC91A and 1.5SMC91A use the DO-214AB surface mount package (SMC variant). Footprint, lead spacing, and thermal characteristics are identical, allowing direct PCB substitution without layout modifications.

Q: What is the significance of the voltage ratings in substitution?

A: The reverse standoff voltage (77.8V), breakdown voltage (86.5V minimum), and clamping voltage (125V maximum) define the protection threshold and response characteristics of the TVS diode. Substitutes must maintain these exact specifications to ensure proper transient suppression in the protected circuit.

Q: Do compliance certifications differ between these parts?

A: The TPSMC91A carries AEC-Q101 automotive qualification. The 1.5SMC91A specification provided does not list this certification. Both parts are ROHS3 compliant and REACH unaffected. Applications requiring automotive-grade qualification should verify AEC-Q101 status with the manufacturer before substitution.

Q: How does the peak pulse current difference affect substitution?

A: The 1.5SMC91A's 12.6A peak pulse rating exceeds the TPSMC91A's 12.2A specification. This higher rating provides additional transient current handling capacity without reducing protection effectiveness. The substitute is suitable for applications designed around the 12.2A specification.

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