P4SMA9.1 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The P4SMA9.1 is a unidirectional Zener-type transient voltage suppressor diode manufactured by Littelfuse, designed for general-purpose overvoltage protection in surface-mount applications. The device features a 7.78V reverse standoff voltage and 14.07V maximum clamping voltage with 30.6A peak pulse current capability in a DO-214AC (SMA) package. The P4SMA9.1 is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	7.78	V
Voltage - Breakdown (Min)	8.22	V
Voltage - Clamping (Max) @ Ipp	14.07	V
Current - Peak Pulse (10/1000µs)	30.6	A
Power - Peak Pulse	400	W
Operating Temperature Range	-65 to 150	°C (TJ)
Package / Case	DO-214AC (SMA)	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the P4SMA9.1 is determined by the following critical electrical and mechanical parameters:

Voltage - Reverse Standoff (Typ): 7.78V ± tolerance
Voltage - Clamping (Max) @ Ipp: 13.4V to 14.07V range
Current - Peak Pulse (10/1000µs): 29.4A to 31A range
Power - Peak Pulse: 400W
Package / Case: DO-214AC (SMA)
Mounting Type: Surface Mount
Type: Zener, Unidirectional
RoHS Status: ROHS3 Compliant

Substitute parts must maintain electrical performance within these specified ranges and preserve the same physical package footprint and mounting characteristics to ensure direct replacement capability in existing PCB designs.

Parameter Comparison

Parameter	P4SMA9.1 (Littelfuse)	P4SMA9.1A (Taiwan Semiconductor)	SMAJ8.0A (Meritek)	SMAJ8.0A-M3/5A (Vishay)
Voltage - Reverse Standoff (Typ)	7.78V	7.78V	8V	8V
Voltage - Breakdown (Min)	8.22V	8.65V	8.89V	8.89V
Voltage - Clamping (Max) @ Ipp	14.07V	13.4V	13.6V	13.6V
Current - Peak Pulse (10/1000µs)	30.6A	31A	29.41A	29.4A
Power - Peak Pulse	400W	400W	400W	400W
Operating Temperature Range	-65 to 150°C	-55 to 150°C	-55 to 150°C	-55 to 150°C
Package / Case	DO-214AC (SMA)	DO-214AC (SMA)	DO-214AC (SMA)	DO-214AC (SMA)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Obsolete	Active	Active	Active

Engineering Selection Recommendations

P4SMA9.1A (Taiwan Semiconductor Corporation) is the primary recommended substitute. This part maintains identical reverse standoff voltage (7.78V) and equivalent clamping voltage (13.4V), with marginally higher peak pulse current (31A vs. 30.6A). The device is active in production with ROHS3 compliance and REACH unaffected status. The narrower operating temperature range (-55 to 150°C vs. -65 to 150°C) is acceptable for most general-purpose applications.

SMAJ8.0A (Meritek) and SMAJ8.0A-M3/5A (Vishay) are secondary alternatives. Both devices operate at 8V reverse standoff voltage with 13.6V clamping voltage and 29.4A peak pulse current. These parts fall within acceptable electrical performance margins for the P4SMA9.1 application space. SMAJ8.0A-M3/5A is supplied in Tape & Reel packaging with active product status and full compliance certifications.

All substitute parts are ROHS3 compliant, surface-mount compatible in DO-214AC (SMA) packages, and rated for 400W peak pulse power dissipation.

Frequently Asked Questions (FAQ)

Q: Can P4SMA9.1A directly replace P4SMA9.1 in existing designs?

A: Yes. P4SMA9.1A maintains the same reverse standoff voltage (7.78V), equivalent clamping voltage (13.4V vs. 14.07V), and identical DO-214AC (SMA) package footprint. Peak pulse current is marginally higher (31A vs. 30.6A), providing equivalent or improved performance.

Q: What is the difference between P4SMA9.1A and SMAJ8.0A substitutes?

A: P4SMA9.1A preserves the 7.78V reverse standoff voltage specification. SMAJ8.0A and SMAJ8.0A-M3/5A operate at 8V reverse standoff voltage, representing a 0.22V increase. Clamping voltages are comparable (13.4V to 13.6V range). Selection depends on circuit voltage tolerance requirements.

Q: Are all substitute parts available in the same package?

A: Yes. All substitute parts use DO-214AC (SMA) surface-mount packages with identical footprints, enabling direct PCB replacement without layout modifications.

Q: What compliance certifications apply to substitute parts?

A: All substitute parts are ROHS3 compliant. P4SMA9.1A and SMAJ8.0A-M3/5A carry REACH unaffected status. Moisture sensitivity level is 1 (Unlimited) for all devices.

Q: Does operating temperature range affect substitution?

A: P4SMA9.1 operates from -65 to 150°C. Substitute parts operate from -55 to 150°C. The 10°C reduction in minimum temperature is acceptable for applications not requiring extended low-temperature performance.

Q: What inventory availability exists for substitute parts?

A: P4SMA9.1A (Taiwan Semiconductor) has 23,750 units in stock. SMAJ8.0A (Meritek) has 15,628 units. SMAJ8.0A-M3/5A (Vishay) has 729 units available.

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