SMAJ45 Equivalent & Substitute Parts

Part Overview

The SMAJ45 is a unidirectional transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. This component features a 45V reverse standoff voltage with a 76.34V maximum clamping voltage and 5.5A peak pulse current capability in a DO-214AC (SMA) package. The SMAJ45 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 meeting RoHS3 compliance and MSL Level 1 moisture sensitivity requirements.

Substiute Parts

SMAJ45

Littelfuse Inc.In Stock: 760SMAJ45 Datasheet

Current PartRFQ

SMAJ45A

MeritekIn Stock: 300376SMAJ45A Datasheet

DirectRFQ

SMAJ45A

MeritekIn Stock: 300376SMAJ45A Datasheet

DirectRFQ

SMAJ45A-13-F

Diodes IncorporatedIn Stock: 15348SMAJ45A-13-F Datasheet

MFR RecommendedRFQ

SMAJ45A-TP

Micro Commercial CoIn Stock: 921SMAJ45A-TP Datasheet

MFR RecommendedRFQ

SMAJ45AE3/TR13

Microchip TechnologyIn Stock: 969SMAJ45AE3/TR13 Datasheet

MFR RecommendedRFQ

SMAJ45E3/TR13

Microchip TechnologyIn Stock: 1173SMAJ45E3/TR13 Datasheet

MFR RecommendedRFQ

TV04A450J-G

Comchip TechnologyIn Stock: 1169TV04A450J-G Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SMAJ45 is determined by the following criteria:

Mandatory Electrical Parameters:

• Voltage - Reverse Standoff (Typ): 45V
• Package / Case: DO-214AC (SMA)
• Type: Zener (unidirectional)
• Unidirectional Channels: 1
• RoHS3 Compliance
• MSL Level 1

Allowable Variation Parameters:

• Voltage - Clamping (Max) @ Ipp: 72.7V to 80.3V (acceptable range for general-purpose protection)
• Current - Peak Pulse (10/1000µs): 5.5A to 6.9A (higher ratings provide enhanced protection margin)
• Power - Peak Pulse: 400W to 500W (proportional to current rating)
• Operating Temperature Range: -55°C to -65°C minimum; 150°C to 175°C maximum (extended ranges acceptable)

All substitute parts listed maintain the 45V standoff voltage and DO-214AC package specification, ensuring direct mechanical and electrical compatibility. Variations in clamping voltage and peak pulse current represent different manufacturer implementations of the same functional specification, all suitable for general-purpose transient suppression applications.

Parameter Comparison

Engineering Selection Recommendations

All listed substitute parts are classified as Active products, ensuring ongoing availability and manufacturing support. Each substitute maintains ROHS3 compliance and MSL Level 1 moisture sensitivity specifications, meeting current regulatory and supply chain requirements.

For direct electrical equivalence: SMAJ45A (Meritek), SMAJ45A-13-F (Diodes Incorporated), and TV04A450J-G (Comchip Technology) provide identical electrical performance to the original SMAJ45, with 72.7V clamping voltage and 5.5A peak pulse current.

For enhanced protection margin: SMAJ45AE3/TR13 (Microchip Technology) offers increased peak pulse current (6.9A) and power dissipation (500W) while maintaining the same 45V standoff voltage and clamping voltage, suitable for applications requiring higher transient energy absorption.

For extended temperature operation: SMAJ45A-TP (Micro Commercial Co) extends the maximum operating temperature to 175°C, accommodating high-temperature circuit environments while maintaining standard electrical ratings.

For higher clamping voltage: SMAJ45E3/TR13 (Microchip Technology) provides 80.3V maximum clamping voltage with 6.2A peak pulse current and 500W power dissipation, appropriate for applications with stricter voltage regulation requirements.

Frequently Asked Questions (FAQ)

Q: Can SMAJ45A substitute directly for the obsolete SMAJ45? A: Yes. SMAJ45A maintains identical reverse standoff voltage (45V), package type (DO-214AC/SMA), and peak pulse current (5.5A). The 72.7V clamping voltage is within the acceptable operating range for general-purpose transient suppression. All compliance certifications (ROHS3, MSL Level 1) are equivalent.

Q: What is the difference between SMAJ45AE3/TR13 and SMAJ45E3/TR13? A: Both are Microchip Technology products with identical 45V standoff voltage and DO-214AC package. SMAJ45AE3/TR13 provides 72.7V clamping voltage with 6.9A peak pulse current (500W), while SMAJ45E3/TR13 provides 80.3V clamping voltage with 6.2A peak pulse current (500W). Selection depends on whether lower clamping voltage with higher current capacity or higher clamping voltage with moderate current capacity is required.

Q: Are all substitute parts available in Tape & Reel packaging? A: Yes. All substitute parts listed are supplied in Tape & Reel (TR) packaging, suitable for automated assembly processes.

Q: Does operating temperature range affect substitution compatibility? A: Operating temperature range does not prevent substitution if the application operates within the substitute part's specified range. SMAJ45A-TP extends to 175°C maximum, while other substitutes operate to 150°C. Verify application requirements before selection.

Q: What is the significance of the different clamping voltages (72.7V, 76.34V, 80.3V)? A: All values fall within acceptable limits for 45V standoff TVS diodes. The clamping voltage represents the maximum voltage across the diode during transient suppression. Lower clamping voltages provide tighter voltage regulation; higher values allow greater voltage excursion. Selection depends on protected circuit voltage tolerance specifications.

Q: Can SMAJ45AE3/TR13 be used in place of SMAJ45A-TP? A: Both are suitable substitutes for the SMAJ45. SMAJ45AE3/TR13 offers higher current capacity (6.9A vs 5.5A) and lower maximum operating temperature (-65°C minimum vs -55°C). SMAJ45A-TP extends to 175°C maximum temperature. Selection depends on thermal environment and transient energy requirements.