SMDJ20 Equivalent & Substitute Parts Reference

Part Overview

The SMDJ20 is a unidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. The device features a 20V reverse standoff voltage with a 34.02V maximum clamping voltage and 92.6A peak pulse current capability in a DO-214AB (SMC) package. The SMDJ20 is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain electrical compatibility across voltage ratings, current handling, and thermal specifications while supporting the same surface-mount package format.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	20	V
Voltage - Breakdown (Min)	21.02	V
Voltage - Clamping (Max) @ Ipp	34.02	V
Current - Peak Pulse (10/1000µs)	92.6	A
Power - Peak Pulse	3000	W
Operating Temperature Range	-65 to 150	°C
Package / Case	DO-214AB, SMC	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution eligibility for the SMDJ20 is determined by the following critical parameters:

Voltage - Reverse Standoff: Must be 20V (±0V tolerance for direct substitution)
Voltage - Clamping (Max) @ Ipp: Must be within 32.4V to 34.02V range
Current - Peak Pulse (10/1000µs): Must be ≥46.3A minimum; 92.6A preferred for full performance equivalence
Power - Peak Pulse: Must be ≥1500W minimum; 3000W preferred for full equivalence
Package / Case: Must be DO-214AB or SMC (equivalent surface-mount packages)
Mounting Type: Must be Surface Mount
Operating Temperature Range: Must support at least -55°C to 150°C
RoHS Status: Must be ROHS3 Compliant

Substitute parts are grouped into two categories: Full Equivalents (matching 92.6A peak pulse current and 3000W power rating) and Functional Equivalents (meeting minimum 46.3A current and 1500W power requirements with acceptable clamping voltage performance).

Parameter Comparison

Manufacturer Part Number	Manufacturer	Voltage - Reverse Standoff (V)	Voltage - Breakdown Min (V)	Voltage - Clamping Max @ Ipp (V)	Current - Peak Pulse (A)	Power - Peak Pulse (W)	Operating Temp (°C)	Package	Product Status
SMDJ20	Littelfuse Inc.	20	21.02	34.02	92.6	3000	-65 to 150	DO-214AB	Obsolete
SMDJ20A	Alpha & Omega Semiconductor Inc.	20	22.2	32.4	92.6	3000	-55 to 150	DO-214AB	Active
SZ1SMC20AT3G	Littelfuse Inc.	20	22.2	32.4	46.3	1500	-65 to 150	SMC	Active
3.0SMCJ20A-13	Diodes Incorporated	20	22.2	32.4	62.6	3000	-55 to 175	SMC	Active
SMCJ20A	Fairchild Semiconductor	20	22.2	32.4	46.3	1500	-55 to 150	SMC	Active
SMCJ20A-TP	Micro Commercial Co	20	22.2	32.4	46.3	1500	-55 to 175	SMC	Active
SMCJ20AE3/TR13	Microchip Technology	20	22.2	32.4	46.3	1500	-65 to 150	SMC	Active
SMLJ20A	Bourns Inc.	20	22.2	32.4	92.6	3000	-55 to 150	SMC	Active
SMLJ20A-TP	Micro Commercial Co	20	22.2	32.4	92.6	3000	-55 to 175	SMC	Active
SMLJ20AE3/TR13	Microchip Technology	20	22.2	32.4	92.6	300	-55 to 150	SMC	Active
TV15C200J-G	Comchip Technology	20	22.2	32.4	46.3	1500	-55 to 150	SMC	Active

Engineering Selection Recommendations

Full Performance Equivalents (92.6A / 3000W):

SMDJ20A (Alpha & Omega Semiconductor Inc.) and SMLJ20A (Bourns Inc.) provide direct electrical equivalence to the SMDJ20 with active product status. Both maintain the 20V reverse standoff voltage, 32.4V clamping voltage, and full 92.6A peak pulse current with 3000W power dissipation. SMDJ20A operates across -55°C to 150°C, while SMLJ20A supports the same range. Both are ROHS3 compliant. SMLJ20A-TP (Micro Commercial Co) extends the upper operating temperature to 175°C while maintaining full electrical specifications and active status.

Functional Equivalents (46.3A / 1500W):

SMCJ20A (Fairchild Semiconductor), SMCJ20A-TP (Micro Commercial Co), SMCJ20AE3/TR13 (Microchip Technology), SZ1SMC20AT3G (Littelfuse Inc.), and TV15C200J-G (Comchip Technology) meet minimum substitution criteria with 46.3A peak pulse current and 1500W power rating. These parts maintain the 20V reverse standoff and 32.4V clamping voltage specifications. SMCJ20AE3/TR13 and SZ1SMC20AT3G support extended temperature ranges (-65°C to 150°C and -65°C to 150°C respectively). All are ROHS3 compliant and active products.

Intermediate Performance:

3.0SMCJ20A-13 (Diodes Incorporated) provides 62.6A peak pulse current with 3000W power rating and extended operating temperature to 175°C, positioning it between functional and full equivalents.

Note: SMLJ20AE3/TR13 (Microchip Technology) shows 300W peak pulse power, which deviates significantly from the 3000W specification and is not recommended for direct substitution in applications requiring full power dissipation capability.

Frequently Asked Questions (FAQ)

Q: Can SMCJ20A replace SMDJ20 in all applications?

A: SMCJ20A is a functional equivalent meeting the 20V reverse standoff and 32.4V clamping voltage requirements. However, it provides 46.3A peak pulse current versus the SMDJ20's 92.6A, and 1500W versus 3000W power dissipation. Applications requiring the full 92.6A current handling or 3000W power capability should use SMDJ20A or SMLJ20A instead.

Q: What is the difference between DO-214AB and SMC packages?

A: DO-214AB and SMC are equivalent surface-mount package designations for the same physical form factor. Parts specified as either package type are mechanically and electrically compatible for PCB assembly.

Q: Why does the SMDJ20 have a higher clamping voltage (34.02V) than most substitutes (32.4V)?

A: The clamping voltage variation falls within acceptable tolerance ranges for TVS diode specifications. The 32.4V clamping voltage of substitute parts remains within functional limits for 20V standoff applications. Applications with strict clamping voltage requirements should specify SMDJ20A or SMLJ20A for closest electrical match.

Q: Are all substitute parts ROHS3 compliant?

A: Yes, all listed substitute parts are ROHS3 compliant, meeting environmental and regulatory requirements equivalent to the original SMDJ20.

Q: Which substitute offers the widest operating temperature range?

A: SMLJ20A-TP and SMCJ20A-TP both support -55°C to 175°C operating temperature. For extended low-temperature operation to -65°C, SMCJ20AE3/TR13, SZ1SMC20AT3G, and the original SMDJ20 specification are available.

Q: Can I use a lower current-rated part (46.3A) in place of the 92.6A SMDJ20?

A: Substitution with lower current-rated parts is application-dependent. If the circuit's transient pulse current does not exceed 46.3A, functional equivalents are acceptable. For circuits generating transient pulses approaching or exceeding 46.3A, full-equivalent parts (SMDJ20A, SMLJ20A) are required to prevent device stress and ensure reliability.

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