P4SMA91C Equivalent & Substitute Parts

Part Overview

The P4SMA91C is a transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This component features a 77.8V reverse standoff voltage with 131.25V maximum clamping voltage and 3.3A peak pulse current capability in a DO-214AC (SMA) package. The part is currently listed as obsolete, necessitating identification of active equivalent and substitute components that maintain functional compatibility within specified electrical and mechanical parameters.

Key Parameters

Parameter	P4SMA91C
Voltage - Reverse Standoff (Typ)	77.8V
Voltage - Breakdown (Min)	82.18V
Voltage - Clamping (Max) @ Ipp	131.25V
Current - Peak Pulse (10/1000µs)	3.3A
Power - Peak Pulse	400W
Package / Case	DO-214AC, SMA
Operating Temperature	-65°C ~ 150°C (TJ)
Type	Zener
Bidirectional Channels	1

Substitute Part Grouping Explanation

Substitution of the P4SMA91C is determined by the following critical parameters: reverse standoff voltage (77.8V nominal), breakdown voltage range (82.18V minimum), clamping voltage (131.25V maximum), peak pulse current (3.3A), power dissipation capability (400W), and package format (DO-214AC/SMA). Substitute parts must maintain compatibility within these electrical specifications and the surface-mount package requirement. The following parts meet these criteria based on their specified electrical characteristics and active product status.

Parameter Comparison

Parameter	P4SMA91C	P4SMA91CA	SMAJ78CA	SMAJ85CA	SMAJ90CA	P4SMA100CA-M3/5A	P4SMA100CA-M3/61	P4SMA110CA-E3/5A	P4SMA110CA-E3/61	P4SMA110CA-M3/5A	P4SMA110CA-M3/61
Manufacturer	Littelfuse Inc.	Eaton - Electronics Division	MDD	Meritek	MDD	Vishay General Semiconductor	Vishay General Semiconductor	Vishay General Semiconductor	Vishay General Semiconductor	Vishay General Semiconductor	Vishay General Semiconductor
Voltage - Reverse Standoff (Typ)	77.8V	77.8V	78V	85V	90V	85.5V	85.5V	94V	94V	94V	94V
Voltage - Breakdown (Min)	82.18V	86.5V	86.7V	94.4V	100V	95V	95V	105V	105V	105V	105V
Voltage - Clamping (Max) @ Ipp	131.25V	125V	126V	137V	146V	137V	137V	152V	152V	152V	152V
Current - Peak Pulse (10/1000µs)	3.3A	3.3A	3.2A	2.92A	2.7A	2.2A	2.2A	2A	2A	2A	2A
Power - Peak Pulse	400W	400W	400W	400W	400W	300W	300W	300W	300W	300W	300W
Package / Case	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA	DO-214AC (SMA)	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA
Operating Temperature	-65°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)	-50°C ~ 150°C (TJ)	-55°C ~ 150°C	-50°C ~ 150°C (TJ)	-65°C ~ 150°C (TJ)	-65°C ~ 150°C (TJ)	-65°C ~ 150°C (TJ)	-65°C ~ 150°C (TJ)	-65°C ~ 150°C (TJ)	-65°C ~ 150°C (TJ)
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	RoHS Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitute: P4SMA91CA

The P4SMA91CA (Eaton - Electronics Division) is the closest electrical equivalent to the P4SMA91C, maintaining identical reverse standoff voltage (77.8V) and peak pulse current (3.3A) specifications. Both components share the same 400W peak pulse power rating and DO-214AC/SMA package format. The P4SMA91CA is active in production with RoHS compliance certification, providing direct functional replacement capability. The operating temperature range is reduced to -55°C ~ 150°C compared to the original -65°C specification; this difference must be evaluated against application requirements.

Secondary Substitutes: SMAJ78CA, SMAJ85CA, SMAJ90CA

These parts provide alternative voltage ratings within the general protection range. SMAJ78CA (MDD) offers the closest voltage standoff (78V) with 126V clamping and 3.2A peak pulse current. SMAJ85CA (Meritek) and SMAJ90CA (MDD) represent higher voltage variants with reduced peak pulse current (2.92A and 2.7A respectively). All three maintain 400W peak pulse power and DO-214AC/SMA package compatibility. Selection among these depends on specific circuit voltage requirements and current handling needs.

Higher Voltage Alternatives: P4SMA100CA and P4SMA110CA Series

The P4SMA100CA variants (Vishay) provide 85.5V standoff voltage with 137V clamping and 2.2A peak pulse current at 300W power dissipation. The P4SMA110CA variants (Vishay) offer 94V standoff voltage with 152V clamping and 2A peak pulse current at 300W power dissipation. These parts are suitable for applications requiring higher voltage protection margins. All Vishay variants maintain the -65°C ~ 150°C operating temperature range and DO-214AC/SMA package format. Multiple packaging options (M3/5A, M3/61, E3/5A, E3/61) are available for supply chain flexibility.

All substitute parts are ROHS3 compliant and carry active product status, ensuring long-term availability and supply chain stability.

Frequently Asked Questions (FAQ)

Q: Can P4SMA91CA directly replace P4SMA91C in all applications?

A: P4SMA91CA maintains identical electrical specifications (77.8V standoff, 3.3A peak pulse, 400W power, DO-214AC/SMA package) and is the primary direct substitute. The operating temperature range is -55°C ~ 150°C versus the original -65°C ~ 150°C; applications operating below -55°C require evaluation of alternative parts.

Q: What is the difference between the various P4SMA110CA packaging options (M3/5A, M3/61, E3/5A, E3/61)?

A: The suffixes indicate different packaging and tape configurations for automated assembly. All variants maintain identical electrical specifications (94V standoff, 152V clamping, 2A peak pulse, 300W power, DO-214AC/SMA package). Selection depends on supply chain availability and assembly equipment compatibility.

Q: Are all substitute parts RoHS compliant?

A: All listed substitute parts carry ROHS3 compliance certification, meeting current environmental and regulatory requirements.

Q: How do the higher voltage P4SMA100CA and P4SMA110CA series differ from the original P4SMA91C?

A: These parts provide higher voltage protection (85.5V and 94V standoff respectively) with correspondingly higher clamping voltages (137V and 152V). Peak pulse current is reduced to 2.2A and 2A respectively, and power dissipation is 300W. These are suitable for circuits requiring higher voltage margins but with lower current transient requirements.

Q: What is the significance of the 400W versus 300W power rating difference?

A: The 400W rating of P4SMA91C and P4SMA91CA indicates higher transient energy absorption capability. Parts rated at 300W (P4SMA100CA and P4SMA110CA series) are suitable for applications with lower energy transients. Circuit design must account for actual transient energy levels to ensure adequate protection.

Q: Can SMAJ78CA, SMAJ85CA, or SMAJ90CA be used as direct replacements?

A: These parts provide alternative voltage ratings and are suitable for circuits where the specific voltage protection level is compatible with application requirements. SMAJ78CA (78V standoff) is closest to the original specification. SMAJ85CA and SMAJ90CA represent higher voltage protection options with reduced peak pulse current capability.

Q: What package format compatibility should be verified?

A: All substitute parts use DO-214AC/SMA surface-mount package format, maintaining mechanical and electrical compatibility with the original P4SMA91C footprint. Verify PCB layout and assembly equipment compatibility with the specific packaging variant selected.

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