SMAT70A-13 Equivalent & Substitute Parts

Part Overview

The SMAT70A-13 is a unidirectional Zener transient voltage suppressor (TVS) diode manufactured by Diodes Incorporated in the DO-214AC (SMA) surface mount package. This component is designed for transient voltage protection applications with a 70V reverse standoff voltage and 100V maximum clamping voltage at 4.6A peak pulse current. The part is currently discontinued at DiGi Electronics, necessitating identification of functionally equivalent alternatives from active product lines that maintain electrical and mechanical compatibility.

Key Parameters

Parameter	Value	Unit
Manufacturer Part Number	SMAT70A-13	—
Manufacturer	Diodes Incorporated	—
Category	Transient Voltage Suppressors (TVS)	—
Type	Zener	—
Unidirectional Channels	1	—
Voltage - Reverse Standoff (Typ)	70	V
Voltage - Breakdown (Min)	77.8	V
Voltage - Clamping (Max) @ Ipp	100	V
Current - Peak Pulse (10/1000µs)	4.6	A
Power - Peak Pulse	400	W
Capacitance @ Frequency	140	pF @ 1MHz
Operating Temperature	-55 to 150	°C (TJ)
Mounting Type	Surface Mount	—
Package / Case	DO-214AC, SMA	—
RoHS Status	RoHS non-compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the SMAT70A-13 is determined by the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - Reverse Standoff (Typ): 70V
Voltage - Clamping (Max) @ Ipp: Must not exceed 100V for direct drop-in replacement
Current - Peak Pulse (10/1000µs): 4.6A minimum
Power - Peak Pulse: 400W
Package / Case: DO-214AC, SMA (surface mount)
Mounting Type: Surface Mount
Unidirectional Channels: 1

Secondary Compatibility Factors:

Operating Temperature Range: -55°C to 150°C minimum
Moisture Sensitivity Level: MSL 1 (Unlimited)
Type: Zener diode

Substitute parts are grouped into two categories:

Category A - Direct Electrical Equivalents (Identical Clamping Voltage): Parts with 70V reverse standoff, 4.6A peak pulse current, and clamping voltage at or below 100V in the SMA package. These provide direct functional replacement without circuit redesign.

Category B - Functional Alternatives (Higher Performance Parameters): Parts with 70V reverse standoff in SMA package but with higher clamping voltage (113V–146V) or higher peak pulse current (16A). These provide enhanced transient suppression capability and are suitable where circuit design permits higher clamping voltages.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff (Typ)	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse (10/1000µs)	Power - Peak Pulse	Package / Case	Operating Temperature	Product Status	RoHS Status
SMAT70A-13	Diodes Incorporated	70V	100V	4.6A	400W	DO-214AC, SMA	-55 to 150°C (TJ)	Discontinued	RoHS non-compliant
SMAT70A-13-F	Diodes Incorporated	70V	100V	4.6A	400W	DO-214AC, SMA	-55 to 150°C (TJ)	Active	ROHS3 Compliant
PTVS64VS1UR,115	Nexperia USA Inc.	64V	103V	3.9A	400W	SOD-123W	-55 to 150°C (TA)	Active	ROHS3 Compliant
SM4T82AY	STMicroelectronics	70V	146V	16A (8/20µs)	400W	DO-214AC, SMA	-55 to 150°C (TJ)	Active	ROHS3 Compliant
SMAJ70A	MDD	70V	113V	4.6A	400W	DO-214AC, SMA	-50 to 150°C (TJ)	Active	ROHS3 Compliant
SMAJ70A-TP	Micro Commercial Co	70V	113V	4.6A	400W	DO-214AC, SMA	-55 to 175°C (TA)	Active	ROHS3 Compliant
SMAJ70A-TR	STMicroelectronics	70V	146V	16A (8/20µs)	400W	DO-214AC, SMA	-55 to 150°C (TJ)	Active	ROHS3 Compliant
SMAJ70CA	MDD	70V	113V	4.6A	400W	DO-214AC, SMA	-50 to 150°C (TJ)	Active	ROHS3 Compliant
SZ1SMA70AT3G	Littelfuse Inc.	70V	113V	4.6A	400W	DO-214AC, SMA	-65 to 150°C (TJ)	Active	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: SMAT70A-13-F

The SMAT70A-13-F is the direct successor to the SMAT70A-13, manufactured by Diodes Incorporated. It maintains identical electrical specifications (70V reverse standoff, 100V clamping voltage, 4.6A peak pulse current) and mechanical compatibility (DO-214AC SMA package). The primary distinction is product status and compliance: SMAT70A-13-F is active in production and ROHS3 compliant, whereas the original SMAT70A-13 is discontinued and RoHS non-compliant. This part requires no circuit redesign and provides direct functional replacement.

Secondary Recommendations for Active Sourcing:

For applications where higher clamping voltage tolerance exists, the following active parts provide equivalent 70V reverse standoff protection in the SMA package:

SMAJ70A (MDD) and SMAJ70A-TP (Micro Commercial Co): Both maintain 70V reverse standoff and 4.6A peak pulse current with 113V clamping voltage. SMAJ70A-TP extends operating temperature to 175°C. Both are ROHS3 compliant and actively produced.
SMAJ70A-TR (STMicroelectronics) and SM4T82AY (STMicroelectronics): Both are TRANSIL™ series parts with 70V reverse standoff in SMA package. These deliver higher peak pulse current (16A at 8/20µs) and higher clamping voltage (146V), suitable for applications requiring enhanced transient suppression.
SZ1SMA70AT3G (Littelfuse Inc.): Maintains 70V reverse standoff and 4.6A peak pulse current with 113V clamping voltage. Offers extended low-temperature operation to -65°C and carries AEC-Q101 automotive qualification.

Not Recommended: PTVS64VS1UR,115 (Nexperia)

This part operates at 64V reverse standoff (6V lower than the original specification) and uses SOD-123W package instead of SMA. While it provides similar clamping voltage and peak pulse current, the lower standoff voltage and different package make it unsuitable as a direct substitute.

Not Recommended: SMAJ70CA (MDD)

This part is bidirectional (2 channels) rather than unidirectional (1 channel) as specified for the SMAT70A-13. Bidirectional TVS diodes are not functionally equivalent to unidirectional devices in circuits designed for single-direction transient suppression.

Frequently Asked Questions (FAQ)

Q: Can SMAT70A-13-F be used as a direct replacement for SMAT70A-13?

A: Yes. SMAT70A-13-F is the active production equivalent with identical electrical specifications (70V reverse standoff, 100V clamping voltage, 4.6A peak pulse current) and mechanical compatibility (DO-214AC SMA package). The only differences are product status (active vs. discontinued) and RoHS compliance (ROHS3 vs. non-compliant). No circuit redesign is required.

Q: What is the difference between unidirectional and bidirectional TVS diodes?

A: Unidirectional TVS diodes (like SMAT70A-13) suppress transients in one direction only and are used in circuits with defined polarity. Bidirectional TVS diodes (like SMAJ70CA) suppress transients in both directions and are used in AC circuits or where polarity is undefined. The SMAT70A-13 is unidirectional; substitutes must maintain this characteristic unless circuit design is modified.

Q: Can I use SMAJ70A or SZ1SMA70AT3G instead of SMAT70A-13?

A: Yes, with circuit validation. Both parts maintain 70V reverse standoff and 4.6A peak pulse current in the SMA package but have higher clamping voltage (113V vs. 100V). If your circuit design permits clamping voltage up to 113V, these parts are functionally suitable. Both are ROHS3 compliant and actively produced. Circuit simulation or testing is necessary to confirm performance in your specific application.

Q: Why is the PTVS64VS1UR,115 not recommended?

A: The PTVS64VS1UR,115 has a 64V reverse standoff voltage, which is 6V lower than the SMAT70A-13 specification of 70V. This lower standoff voltage may cause premature triggering in circuits designed for 70V protection. Additionally, it uses SOD-123W package instead of SMA, requiring PCB layout changes. It is not a suitable substitute.

Q: What does RoHS compliance mean for TVS diode selection?

A: RoHS (Restriction of Hazardous Substances) compliance indicates the part does not contain restricted materials such as lead, cadmium, or mercury. ROHS3 compliant parts (like SMAT70A-13-F) meet current regulatory requirements for electronics manufacturing and are required for many industrial and consumer applications. The original SMAT70A-13 is RoHS non-compliant and may not be acceptable for new designs or regulated markets.

Q: Can I use SM4T82AY or SMAJ70A-TR for higher transient current protection?

A: Yes, if your circuit design permits. Both parts deliver 16A peak pulse current (vs. 4.6A in SMAT70A-13) and 146V clamping voltage. They maintain 70V reverse standoff and SMA package compatibility. These higher-performance parts are suitable for applications requiring enhanced transient suppression. Circuit validation is necessary to confirm the higher clamping voltage does not interfere with downstream components.

Q: What is the significance of operating temperature range differences?

A: Operating temperature range defines the thermal limits within which the part maintains specified electrical performance. SMAT70A-13 operates from -55°C to 150°C. Substitutes like SMAJ70A-TP extend to 175°C, providing margin for high-temperature applications. SZ1SMA70AT3G extends to -65°C for low-temperature environments. Select based on your application's thermal requirements.

Q: Are all SMA package TVS diodes mechanically interchangeable?

A: Yes, all parts specified as DO-214AC (SMA) package are mechanically interchangeable on the PCB. However, electrical parameters (voltage, current, clamping voltage) differ between parts. Mechanical compatibility does not guarantee functional equivalence. Always verify electrical specifications match your circuit requirements.

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