SMAJ70C Equivalent & Substitute Parts

Part Overview

The SMAJ70C 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 70V reverse standoff voltage with a 118.65V maximum clamping voltage and 4.6A peak pulse current capability in a DO-214AC (SMA) package. The SMAJ70C is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	Value
Voltage - Reverse Standoff (Typ)	70V
Voltage - Breakdown (Min)	73.71V
Voltage - Clamping (Max) @ Ipp	118.65V
Current - Peak Pulse (10/1000µs)	4.6A
Power - Peak Pulse	400W
Package / Case	DO-214AC, SMA
Operating Temperature	-65°C ~ 150°C (TJ)
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the SMAJ70C are qualified based on the following electrical and mechanical parameters:

Critical Matching Parameters:

Voltage - Reverse Standoff: 70V (all substitutes match)
Voltage - Breakdown (Min): 77.8V (all substitutes match or exceed)
Package / Case: DO-214AC, SMA (all substitutes match)
Mounting Type: Surface Mount (all substitutes match)
RoHS Status: ROHS3 Compliant (all substitutes match)
MSL Rating: 1 (Unlimited) (all substitutes match)

Allowable Variation Parameters:

Voltage - Clamping (Max) @ Ipp: 113V to 146V (within acceptable range for 70V standoff class)
Current - Peak Pulse: 4.6A to 27A (higher ratings provide equivalent or superior protection)
Power - Peak Pulse: 400W to 600W (higher ratings provide equivalent or superior protection)
Operating Temperature: -50°C to -65°C minimum; 150°C to 175°C maximum (all meet or exceed original specification)

Substitutes are grouped into two categories: direct electrical equivalents (matching clamping voltage and current specifications) and enhanced-performance alternatives (higher current or power ratings with compatible voltage characteristics).

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse	Power - Peak Pulse	Operating Temperature	Product Status
SMAJ70C	Littelfuse Inc.	70V	118.65V	4.6A	400W	-65°C ~ 150°C	Obsolete
SMAJ70CA	MDD	70V	113V	4.6A	400W	-50°C ~ 150°C	Active
SZ1SMA70CAT3G	Littelfuse Inc.	70V	113V	4.6A	400W	-65°C ~ 150°C	Active
SMA6J70CA-TR	STMicroelectronics	70V	120V	27A (8/20µs)	600W	-55°C ~ 175°C	Active
SMAJ70CA-13-F	Diodes Incorporated	70V	113V	4.6A	400W	-55°C ~ 150°C	Active
SMAJ70CA-TP	Micro Commercial Co	70V	113V	4.6A	400W	-55°C ~ 175°C	Active
SMAJ70CA-TR	STMicroelectronics	70V	146V	16A (8/20µs)	400W	-55°C ~ 150°C	Active
SMAJ70CAE3/TR13	Microchip Technology	70V	113V	4.4A	500W	-65°C ~ 150°C	Active
SMAJ70CE3/TR13	Microchip Technology	70V	125V	4A	500W	-65°C ~ 150°C	Active
TV04A700JB-G	Comchip Technology	70V	113V	4.64A	400W	-55°C ~ 150°C	Active

Engineering Selection Recommendations

Direct Electrical Equivalents (Recommended for Drop-In Replacement):

SMAJ70CA (MDD), SMAJ70CA-13-F (Diodes Incorporated), SMAJ70CA-TP (Micro Commercial Co), and TV04A700JB-G (Comchip Technology) provide electrical specifications matching the original SMAJ70C within acceptable tolerances. All are active products with ROHS3 compliance and MSL 1 rating. These parts are suitable for direct substitution where the original -65°C minimum operating temperature is not required.

Littelfuse Equivalent (Temperature-Matched):

SZ1SMA70CAT3G (Littelfuse Inc.) maintains the original -65°C to 150°C operating temperature range and is manufactured by the original component supplier. This part is qualified to AEC-Q101 automotive standards and includes capacitance specification (95pF @ 1MHz). Selection of this part preserves the full temperature performance envelope of the original design.

Enhanced-Performance Alternatives:

SMAJ70CAE3/TR13 (Microchip Technology) and SMAJ70CE3/TR13 (Microchip Technology) offer increased peak pulse current (4.4A and 4A respectively) and power dissipation (500W), providing margin for higher transient stress conditions while maintaining the -65°C minimum temperature rating. These parts are suitable where additional protection margin is beneficial.

SMA6J70CA-TR and SMAJ70CA-TR (STMicroelectronics) represent higher-performance variants with significantly increased current handling (27A and 16A respectively) and extended temperature range to 175°C. These parts are appropriate for applications requiring enhanced transient suppression capability or operation in elevated-temperature environments.

Frequently Asked Questions (FAQ)

Q: Can SMAJ70CA directly replace SMAJ70C?

A: Yes. SMAJ70CA shares the same 70V reverse standoff voltage, 113V clamping voltage, 4.6A peak pulse current, and DO-214AC package. The primary difference is product status (active vs. obsolete) and a slightly reduced minimum operating temperature (-50°C vs. -65°C). For applications not requiring the full -65°C rating, SMAJ70CA is a direct substitute.

Q: What is the difference between 113V and 118.65V clamping voltage?

A: Both voltages fall within the acceptable clamping range for 70V standoff TVS diodes. The SMAJ70C specifies 118.65V maximum clamping, while most substitutes specify 113V maximum. This 5.65V difference is within normal manufacturing tolerance for this device class and does not affect circuit compatibility for general-purpose overvoltage protection applications.

Q: Should I use SZ1SMA70CAT3G if my design requires -65°C operation?

A: SZ1SMA70CAT3G is the appropriate selection if your application requires the full -65°C to 150°C operating temperature range. This part is manufactured by Littelfuse (the original supplier) and maintains identical electrical specifications and temperature performance to the obsolete SMAJ70C.

Q: What is the advantage of higher-current alternatives like SMA6J70CA-TR?

A: Higher-current variants (27A for SMA6J70CA-TR vs. 4.6A for SMAJ70C) provide increased transient suppression capability and margin for higher-energy surge events. These parts are suitable for applications experiencing higher transient stress or where design margin is required. The 70V standoff voltage remains identical, ensuring circuit compatibility.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts are ROHS3 compliant with MSL 1 (Unlimited) moisture sensitivity rating, matching the environmental compliance of the original SMAJ70C.

Q: Can I use SMAJ70CA-TP with extended temperature range (-55°C to 175°C)?

A: Yes. SMAJ70CA-TP (Micro Commercial Co) offers an extended operating temperature range of -55°C to 175°C compared to the original -65°C to 150°C. This part is suitable for applications requiring higher maximum operating temperature, though the minimum temperature is limited to -55°C.

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