SMAJ7.5 Transient Voltage Suppressor (TVS) Diode - Equivalent & Substitute Parts

Part Overview

The SMAJ7.5 is a unidirectional Zener-type transient voltage suppressor diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. The device features a 7.5V reverse standoff voltage with a 14.65V maximum clamping voltage at peak pulse current, housed in a DO-214AC (SMA) package. The SMAJ7.5 is classified as obsolete, necessitating identification of active equivalent and substitute parts that maintain electrical and mechanical compatibility for new designs and production continuity.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	7.5	V
Voltage - Breakdown (Min)	7.89	V
Voltage - Clamping (Max) @ Ipp	14.65	V
Current - Peak Pulse (10/1000µs)	31	A
Power - Peak Pulse	400	W
Operating Temperature Range	-65°C to 150°C	TJ
Package / Case	DO-214AC, SMA	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the SMAJ7.5 is determined by the following critical electrical and mechanical parameters:

Reverse Standoff Voltage (Typ): Must be 7.5V to maintain circuit protection threshold
Package / Case: Must be DO-214AC (SMA) for mechanical and thermal compatibility
Mounting Type: Must be Surface Mount
Voltage - Clamping (Max) @ Ipp: Acceptable range 12.9V to 14.3V (within ±7% of original 14.65V specification)
Current - Peak Pulse (10/1000µs): Acceptable range 31A to 38.8A (maintains or exceeds original 31A specification)
Power - Peak Pulse: Acceptable range 400W to 500W
Operating Temperature Range: Must support minimum -55°C to 150°C
RoHS Status: Must be ROHS3 Compliant

All substitute parts listed maintain these critical parameters within acceptable engineering tolerances for direct substitution.

Parameter Comparison

Parameter	SMAJ7.5 (Littelfuse)	SMAJ7.5A (Meritek)	SMAJ7.5A-13-F (Diodes Inc.)	SMAJ7.5A-TP (Micro Commercial)	SMAJ7.5AE3/TR13 (Microchip)	SMAJ7.5E3/TR13 (Microchip)
Voltage - Reverse Standoff (Typ)	7.5V	7.5V	7.5V	7.5V	7.5V	7.5V
Voltage - Breakdown (Min)	7.89V	8.33V	8.33V	8.33V	8.33V	8.33V
Voltage - Clamping (Max) @ Ipp	14.65V	12.9V	12.9V	12.9V	12.9V	14.3V
Current - Peak Pulse (10/1000µs)	31A	31.01A	31A	31A	38.8A	35A
Power - Peak Pulse	400W	400W	400W	400W	500W	500W
Operating Temperature Range	-65°C to 150°C	-55°C to 150°C	-55°C to 150°C	-55°C to 175°C	-65°C to 150°C	-65°C to 150°C
Package / Case	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA	DO-214AC, SMA
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes (Recommended for New Designs)

SMAJ7.5A (Meritek), SMAJ7.5A-13-F (Diodes Incorporated), and SMAJ7.5A-TP (Micro Commercial Co) are functionally equivalent to the original SMAJ7.5. All three maintain the 7.5V reverse standoff voltage, operate within acceptable clamping voltage tolerance (12.9V), and support peak pulse currents of 31A. All are ROHS3 compliant and actively manufactured. These parts are suitable for direct substitution in existing designs.

Enhanced Performance Alternatives

SMAJ7.5AE3/TR13 (Microchip Technology) and SMAJ7.5E3/TR13 (Microchip Technology) offer increased peak pulse current and power dissipation capabilities (38.8A / 500W and 35A / 500W respectively) while maintaining the 7.5V reverse standoff voltage. SMAJ7.5AE3/TR13 provides the widest operating temperature range (-65°C to 150°C), matching the original specification. SMAJ7.5E3/TR13 features a slightly elevated clamping voltage (14.3V) within acceptable tolerance. Both are ROHS3 compliant and actively produced.

Temperature Consideration

SMAJ7.5A-TP (Micro Commercial Co) supports an extended upper operating temperature of 175°C, providing thermal margin for high-temperature applications compared to the original -65°C to 150°C specification.

Frequently Asked Questions (FAQ)

Q: Can SMAJ7.5A (Meritek) be used as a direct replacement for SMAJ7.5 (Littelfuse)?

A: Yes. SMAJ7.5A maintains the critical 7.5V reverse standoff voltage, operates within acceptable clamping voltage range (12.9V vs. 14.65V original), and supports equivalent peak pulse current (31.01A). The DO-214AC (SMA) package and surface-mount configuration are identical. Both are ROHS3 compliant.

Q: What is the difference between SMAJ7.5AE3/TR13 and SMAJ7.5E3/TR13?

A: Both are Microchip Technology products with enhanced specifications. SMAJ7.5AE3/TR13 provides 38.8A peak pulse current and maintains the original -65°C to 150°C temperature range. SMAJ7.5E3/TR13 provides 35A peak pulse current with a slightly higher clamping voltage (14.3V). Both support 500W peak pulse power. Selection depends on whether peak current capacity or clamping voltage precision is prioritized.

Q: Are all substitute parts available in Tape & Reel (TR) packaging?

A: Yes. All listed substitute parts are supplied in Tape & Reel (TR) packaging, suitable for automated assembly processes.

Q: Does the clamping voltage variation between substitutes affect circuit protection?

A: The clamping voltage range (12.9V to 14.3V) represents acceptable engineering tolerance around the original 14.65V specification. All values remain within ±7% and maintain the intended overvoltage protection function. Circuit design should account for this tolerance range during validation.

Q: Which substitute offers the best thermal performance?

A: SMAJ7.5A-TP (Micro Commercial Co) supports the highest operating temperature (up to 175°C), providing additional thermal margin. SMAJ7.5AE3/TR13 and SMAJ7.5E3/TR13 (Microchip) support 500W peak pulse power versus 400W for other substitutes, enabling better thermal dissipation under transient conditions.

Q: Are all substitutes RoHS compliant?

A: Yes. All listed substitute parts are ROHS3 compliant, meeting environmental and regulatory requirements equivalent to the original SMAJ7.5.

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