1SMA40CAT3G Equivalent & Substitute Parts

Part Overview

The 1SMA40CAT3G is a transient voltage suppressor (TVS) diode manufactured by Littelfuse, classified as a Zener-type bidirectional TVS in the DO-214AC (SMA) surface mount package. This component is designed for general-purpose transient voltage suppression applications with a 40V reverse standoff voltage and 64.5V maximum clamping voltage. The part is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Manufacturer Part Number	1SMA40CAT3G
Manufacturer	Littelfuse
Category	Transient Voltage Suppressors (TVS)
Type	Zener
Package / Case	DO-214AC, SMA
Voltage - Reverse Standoff (Typ)	40V
Voltage - Breakdown (Min)	44.4V
Voltage - Clamping (Max) @ Ipp	64.5V
Current - Peak Pulse (10/1000µs)	6.2A
Power - Peak Pulse	400W
Operating Temperature Range	-65°C ~ 150°C (TJ)
Bidirectional Channels	1
RoHS Status	ROHS3 Compliant
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the 1SMA40CAT3G is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - Reverse Standoff: 40V (exact match required)
Voltage - Breakdown (Min): 44.4V (exact match required)
Voltage - Clamping (Max) @ Ipp: 64.5V (exact match required)
Current - Peak Pulse (10/1000µs): 6.2A (exact match required)
Power - Peak Pulse: 400W (exact match required)
Package / Case: DO-214AC, SMA (exact match required)
Type: Zener, Bidirectional (exact match required)

Secondary Compatibility Factors:

Operating Temperature Range: Minimum -55°C acceptable (original: -65°C)
RoHS Status: ROHS3 Compliant (all substitutes meet this requirement)
Mounting Type: Surface Mount (all substitutes use this type)

Substitute parts are grouped into two categories:

Category A - Direct Electrical & Package Equivalents (SMA Package, 6.2A): Parts with identical electrical specifications and SMA package form factor. These are pin-for-pin and functionally equivalent replacements.

Category B - Higher Current Alternative (SMC Package, 23.3A): The SMCJ40CA offers the same voltage specifications but in a larger SMC (DO-214AB) package with increased current handling (23.3A) and power dissipation (1500W). This part is suitable only if PCB layout and thermal management accommodate the larger package.

Parameter Comparison

Parameter	1SMA40CAT3G (Original)	SMAJ40CA	ATV04A400JB-HF	SMAJ40CA-13-F	SMAJ40CA-E3/61	SMAJ40CA-M3/5A	SMAJ40CA-M3/61	SMAJ40CA-TP	TV04A400JB-G	SMCJ40CA
Manufacturer	Littelfuse	Good-Ark Semiconductor	Comchip Technology	Diodes Incorporated	Vishay General Semiconductor	Vishay General Semiconductor	Vishay General Semiconductor	Micro Commercial Co	Comchip Technology	MDD
Voltage - Reverse Standoff (Typ)	40V	40V	40V	40V	40V	40V	40V	40V	40V	40V
Voltage - Breakdown (Min)	44.4V	44.4V	44.4V	44.4V	44.4V	44.4V	44.4V	44.4V	44.4V	44.4V
Voltage - Clamping (Max) @ Ipp	64.5V	64.5V	64.5V	64.5V	64.5V	64.5V	64.5V	64.5V	64.5V	64.5V
Current - Peak Pulse (10/1000µs)	6.2A	6.2A	6.2A	6.2A	6.2A	6.2A	6.2A	6.2A	6.2A	23.3A
Power - Peak Pulse	400W	400W	400W	400W	400W	400W	400W	400W	400W	1500W
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-214AB, SMC
Operating Temperature Range	-65°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)	-55°C ~ 150°C (TJ)	-55°C ~ 175°C (TA)	-55°C ~ 150°C (TJ)	-50°C ~ 150°C (TJ)
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active	Active
Type	Zener	Zener	Zener	Zener	Zener	Zener	Zener	Zener	Zener	Zener
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (SMA Package, 6.2A Peak Pulse):

All parts listed in Category A—SMAJ40CA, ATV04A400JB-HF, SMAJ40CA-13-F, SMAJ40CA-E3/61, SMAJ40CA-M3/5A, SMAJ40CA-M3/61, SMAJ40CA-TP, and TV04A400JB-G—are electrically and mechanically equivalent to the 1SMA40CAT3G. All are active products with ROHS3 compliance and identical voltage and current specifications. Selection among these parts is based on availability, packaging format (Cut Tape vs. Tape & Reel), and manufacturer preference.

ATV04A400JB-HF and TV04A400JB-G carry AEC-Q101 automotive qualification, suitable for applications requiring automotive-grade components.

SMAJ40CA-TP offers the widest operating temperature range (-55°C ~ 175°C), providing additional thermal margin in high-temperature environments.

For Higher Current Applications (SMC Package, 23.3A Peak Pulse):

The SMCJ40CA is suitable only if the application requires higher transient current handling (23.3A vs. 6.2A) and increased power dissipation (1500W vs. 400W). This part requires a larger PCB footprint (DO-214AB vs. DO-214AC) and is not a pin-for-pin replacement. Use only if thermal and layout constraints permit the larger package.

Frequently Asked Questions (FAQ)

Q: Can I use SMCJ40CA as a direct replacement for 1SMA40CAT3G?

A: No. While SMCJ40CA has identical voltage specifications, it uses a different package (DO-214AB/SMC vs. DO-214AC/SMA). The larger SMC package is not pin-compatible with SMA footprints. Use SMCJ40CA only if your PCB layout and thermal design accommodate the larger package and you require the higher current rating (23.3A).

Q: What is the difference between the various SMAJ40CA variants (SMAJ40CA-13-F, SMAJ40CA-E3/61, SMAJ40CA-M3/5A, SMAJ40CA-M3/61, SMAJ40CA-TP)?

A: These variants differ in packaging format and manufacturer specifications. SMAJ40CA-13-F and SMAJ40CA-E3/61 are supplied in Cut Tape format. SMAJ40CA-M3/5A, SMAJ40CA-M3/61, and SMAJ40CA-TP are supplied in Tape & Reel format. SMAJ40CA-TP offers the widest operating temperature range (-55°C ~ 175°C). All are electrically identical with 40V standoff, 64.5V clamping, and 6.2A peak pulse specifications.

Q: Are ATV04A400JB-HF and TV04A400JB-G suitable for automotive applications?

A: Yes. Both parts carry AEC-Q101 automotive qualification and are graded for automotive use. They are suitable for applications requiring automotive-grade transient voltage suppression.

Q: What is the minimum operating temperature difference between the original part and substitutes?

A: The original 1SMA40CAT3G operates from -65°C; most substitutes operate from -55°C, a 10°C difference at the lower end. SMAJ40CA-TP extends to -55°C minimum. If your application requires operation below -55°C, verify thermal performance with the substitute part's datasheet.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed are ROHS3 compliant, matching the original part's compliance status.

Q: Can I mix different manufacturers' parts in the same design?

A: Yes. All substitute parts meet identical electrical specifications (40V standoff, 64.5V clamping, 6.2A peak pulse, 400W power) and are ROHS3 compliant. Mixing manufacturers is acceptable from an electrical standpoint; however, verify packaging format consistency (Cut Tape vs. Tape & Reel) for assembly compatibility.

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