SMAJ20C Equivalent & Substitute Parts

Part Overview

The SMAJ20C 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 20V reverse standoff voltage with a 34.02V maximum clamping voltage and 12.3A peak pulse current capability in a DO-214AC (SMA) package. The SMAJ20C is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Voltage - Reverse Standoff (Typ)	20V
Voltage - Breakdown (Min)	21.02V
Voltage - Clamping (Max) @ Ipp	34.02V
Current - Peak Pulse (10/1000µs)	12.3A
Power - Peak Pulse	400W
Operating Temperature Range	-65°C ~ 150°C (TJ)
Package / Case	DO-214AC, SMA
Type	Zener
Bidirectional Channels	1
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the SMAJ20C is determined by strict alignment of the following electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - Reverse Standoff (Typ): 20V
Voltage - Breakdown (Min): 22.2V (acceptable range for 20V standoff class)
Package / Case: DO-214AC, SMA
Type: Zener, Bidirectional, Single Channel
Mounting Type: Surface Mount
RoHS Status: ROHS3 Compliant

Secondary Compatibility Parameters:

Current - Peak Pulse (10/1000µs): 12.3A minimum
Power - Peak Pulse: 400W minimum
Operating Temperature: -55°C to 150°C minimum range
Moisture Sensitivity Level (MSL): 1 (Unlimited)

Substitute parts are grouped into two categories: direct electrical equivalents with identical clamping voltage specifications, and functionally compatible alternatives with higher current and power ratings that maintain the same voltage protection class.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse	Power - Peak Pulse	Operating Temperature	Product Status	Package
SMAJ20C	Littelfuse Inc.	20V	34.02V	12.3A	400W	-65°C ~ 150°C	Obsolete	DO-214AC, SMA
SMAJ20CA	MDD	20V	32.4V	12.3A	400W	-50°C ~ 150°C	Active	DO-214AC, SMA
SMAJ20CA-13-F	Diodes Incorporated	20V	32.4V	12.3A	400W	-55°C ~ 150°C	Active	DO-214AC, SMA
SMAJ20CA-TP	Micro Commercial Co	20V	32.4V	12.3A	400W	-55°C ~ 175°C	Active	DO-214AC, SMA
SMAJ20CAE3/TR13	Microchip Technology	20V	32.4V	15.4A	500W	-65°C ~ 150°C	Active	DO-214AC, SMA
SMAJ20CE3/TR13	Microchip Technology	20V	35.8V	13.9A	500W	-65°C ~ 150°C	Active	DO-214AC, SMA
TV04A200JB-G	Comchip Technology	20V	32.4V	12.35A	400W	-55°C ~ 150°C	Active	DO-214AC, SMA
SM4T23CAY	STMicroelectronics	20V	42.8V	54A (8/20µs)	400W	-55°C ~ 150°C	Active	DO-214AC, SMA
SMA6J20CA-TR	STMicroelectronics	20V	36.8V	93A (8/20µs)	600W	-55°C ~ 175°C	Active	DO-214AC, SMA

Engineering Selection Recommendations

Direct Equivalents (Recommended Primary Substitutes):

SMAJ20CA-13-F (Diodes Incorporated), SMAJ20CA-TP (Micro Commercial Co), and TV04A200JB-G (Comchip Technology) are direct functional equivalents to the SMAJ20C. These parts maintain the 20V reverse standoff voltage class, 32.4V clamping voltage, and 12.3A peak pulse current specification. All three are active products with ROHS3 compliance and MSL 1 rating. SMAJ20CA-13-F and TV04A200JB-G support the full -55°C to 150°C operating range, while SMAJ20CA-TP extends to -55°C to 175°C, providing additional thermal margin for high-temperature applications.

Enhanced Performance Alternatives:

SMAJ20CAE3/TR13 and SMAJ20CE3/TR13 (both Microchip Technology) offer increased current and power handling while maintaining the 20V voltage class. SMAJ20CAE3/TR13 provides 15.4A peak pulse current and 500W power dissipation with -65°C to 150°C temperature range. SMAJ20CE3/TR13 delivers 13.9A peak pulse current, 500W power, and 35.8V clamping voltage, also rated -65°C to 150°C. These parts are suitable for applications requiring higher transient energy absorption.

Higher Current Capacity Options:

SM4T23CAY (STMicroelectronics) and SMA6J20CA-TR (STMicroelectronics) are functionally compatible alternatives with significantly higher current ratings (54A and 93A respectively) and enhanced power dissipation (400W and 600W). These parts maintain the 20V voltage class but feature higher clamping voltages (42.8V and 36.8V). Selection of these parts is appropriate only when circuit design permits the higher clamping voltage specification.

All recommended substitutes are active products with ROHS3 compliance, MSL 1 rating, and DO-214AC (SMA) package compatibility.

Frequently Asked Questions (FAQ)

Q: Can SMAJ20CA-13-F directly replace SMAJ20C in existing designs?

A: Yes. SMAJ20CA-13-F maintains identical voltage protection specifications (20V standoff, 32.4V clamping) and current rating (12.3A). The part is pin-compatible in DO-214AC (SMA) package and meets all compliance requirements. No circuit modifications are required.

Q: What is the difference between the 32.4V and 35.8V clamping voltage options?

A: SMAJ20CAE3/TR13 clamps at 32.4V maximum, while SMAJ20CE3/TR13 clamps at 35.8V maximum. Both maintain the 20V reverse standoff voltage class. Selection depends on circuit tolerance for transient voltage peaks. Lower clamping voltage (32.4V) provides tighter protection; higher clamping voltage (35.8V) reduces component stress during transient events.

Q: Are SM4T23CAY and SMA6J20CA-TR suitable substitutes for general-purpose applications?

A: These parts are functionally compatible but feature higher clamping voltages (42.8V and 36.8V respectively) and significantly higher current ratings (54A and 93A). They are appropriate only when circuit design specifications permit the higher clamping voltage. For standard 20V protection applications, direct equivalents with 32.4V clamping are preferred.

Q: What is the temperature range consideration when selecting a substitute?

A: The SMAJ20C operates from -65°C to 150°C. Most active substitutes support -55°C to 150°C minimum. SMAJ20CA-TP extends to 175°C, and SMAJ20CAE3/TR13 and SMAJ20CE3/TR13 match the original -65°C specification. For applications requiring the full -65°C lower temperature limit, select Microchip Technology parts or verify circuit requirements.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All recommended substitute parts listed are ROHS3 compliant with MSL 1 (Unlimited) moisture sensitivity rating, matching the original SMAJ20C specification.

Q: What is the significance of the DO-214AC (SMA) package specification?

A: DO-214AC and SMA are equivalent designations for the same surface-mount package. All substitute parts use this identical package, ensuring mechanical and electrical compatibility with existing PCB layouts and assembly processes. No footprint modifications are required.

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