SMAJ48-E3/5A Equivalent & Substitute Parts

Part Overview

The SMAJ48-E3/5A is a unidirectional transient voltage suppressor (TVS) diode manufactured by Vishay General Semiconductor - Diodes Division, designed for general-purpose overvoltage protection in surface-mount applications. This component features a 48V reverse standoff voltage, 85.5V maximum clamping voltage, and 4.7A peak pulse current capability in a DO-214AC (SMA) package. The part is classified as obsolete, necessitating identification of active equivalent and substitute components that maintain functional compatibility within specified electrical and mechanical parameters.

Key Parameters

Parameter	Value	Unit
Voltage - Reverse Standoff (Typ)	48	V
Voltage - Breakdown (Min)	53.3	V
Voltage - Clamping (Max) @ Ipp	85.5	V
Current - Peak Pulse (10/1000µs)	4.7	A
Power - Peak Pulse	400	W
Operating Temperature Range	-55 to 150	°C (TJ)
Package / Case	DO-214AC, SMA	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the SMAJ48-E3/5A is determined by the following critical parameters:

Reverse Standoff Voltage: 48V nominal (allows 47.6V to 51V range based on part specifications)
Breakdown Voltage (Min): 53.3V minimum (allows up to 56.7V)
Clamping Voltage (Max): 85.5V reference (allows range 77.4V to 100V)
Peak Pulse Current: 4.7A minimum (allows 5.2A and higher)
Power Dissipation: 400W minimum (allows 500W and 600W)
Package: DO-214AC (SMA) surface mount
Temperature Range: -55°C to 150°C minimum operating window

Substitute parts are grouped into three categories based on electrical performance:

Category A - Direct Electrical Equivalents (77.4V Clamp, 5.2A Ipp): SMAJ48A-E3/5A, SMAJ48A, SMAJ48A-TP, SMAJ48A-13-F, SMAJ48AE3/TR13. These maintain the same reverse standoff voltage with slightly lower clamping voltage and higher peak pulse current.

Category B - Higher Performance Variants (88.4V to 100V Clamp, 23A to 40A Ipp): SM4T56AY, SMA6J48A-TR, SMA6T56AY, SMAJ48A-TR. These provide enhanced current handling and power dissipation while maintaining the 48V standoff voltage window.

Category C - Voltage-Shifted Alternative (51V Standoff, 82.4V Clamp, 4.9A Ipp): PTVS51VS1UR,115. This part operates at a higher standoff voltage with automotive-grade qualification.

Parameter Comparison

Part Number	Manufacturer	Standoff Voltage (V)	Breakdown Min (V)	Clamp Max (V)	Peak Pulse (A)	Power (W)	Package	Status
SMAJ48-E3/5A	Vishay	48	53.3	85.5	4.7	400	DO-214AC	Obsolete
SMAJ48A-E3/5A	Vishay	48	53.3	77.4	5.2	400	DO-214AC	Active
SMAJ48A	MDD	48	53.3	77.4	5.2	400	DO-214AC	Active
SMAJ48A-TP	Micro Commercial Co	48	53.3	77.4	5.2	400	DO-214AC	Active
SMAJ48A-13-F	Diodes Incorporated	48	53.3	77.4	5.2	400	DO-214AC	Active
SMAJ48AE3/TR13	Microchip Technology	48	53.3	77.4	6.5	500	DO-214AC	Active
SM4T56AY	STMicroelectronics	48	53.3	100	23	400	DO-214AC	Active
SMA6J48A-TR	STMicroelectronics	48	53.3	88.4	40	600	DO-214AC	Active
SMA6T56AY	STMicroelectronics	47.6	53.2	100	40	600	DO-214AC	Active
SMAJ48A-TR	STMicroelectronics	48	53.3	100	23	400	DO-214AC	Active
PTVS51VS1UR,115	Nexperia USA Inc.	51	56.7	82.4	4.9	400	SOD-123W	Active

Engineering Selection Recommendations

Primary Substitutes (Recommended for Direct Replacement)

SMAJ48A-E3/5A, SMAJ48A-TP, SMAJ48A-13-F, and SMAJ48A are the preferred direct substitutes. All maintain the 48V reverse standoff voltage, 53.3V minimum breakdown voltage, and DO-214AC package compatibility. These parts are active products with ROHS3 compliance and unlimited moisture sensitivity rating (MSL 1). The slightly lower clamping voltage (77.4V vs. 85.5V) and higher peak pulse current (5.2A vs. 4.7A) provide improved performance margins within the same power envelope.

Enhanced Performance Alternatives

SMAJ48AE3/TR13 (Microchip Technology) offers increased peak pulse current (6.5A) and power dissipation (500W) while maintaining electrical compatibility. SM4T56AY and SMAJ48A-TR (STMicroelectronics) provide significantly higher current handling (23A) with 100V clamping voltage, suitable for applications requiring greater transient energy absorption. SMA6J48A-TR and SMA6T56AY deliver maximum performance with 40A peak pulse current and 600W power dissipation for demanding protection circuits.

Voltage-Shifted Alternative

PTVS51VS1UR,115 (Nexperia USA Inc.) operates at 51V standoff voltage with automotive-grade qualification (AEC-Q101). This part is suitable only when the higher voltage threshold is acceptable and automotive compliance is required. Package change to SOD-123W requires PCB layout modification.

Compliance Considerations

All recommended substitutes maintain ROHS3 compliance and EAR99 export classification. Operating temperature ranges vary: most parts support -55°C to 150°C; SMAJ48A-TP extends to -55°C to 175°C; SMA6T56AY operates -40°C to 150°C. Select based on thermal environment requirements.

Frequently Asked Questions (FAQ)

Q: Can SMAJ48A-E3/5A directly replace SMAJ48-E3/5A without circuit modification?

A: Yes. Both parts share identical reverse standoff voltage (48V), breakdown voltage (53.3V minimum), and DO-214AC package. The lower clamping voltage (77.4V vs. 85.5V) and higher peak pulse current (5.2A vs. 4.7A) represent improved performance within the same electrical class.

Q: What is the difference between the 77.4V clamp group and the 100V clamp group?

A: The 77.4V group (SMAJ48A variants) maintains the original clamping characteristic with standard current handling (5.2A). The 100V group (SM4T56AY, SMAJ48A-TR) provides higher voltage clamping with significantly increased peak pulse current (23A), suitable for circuits requiring greater transient suppression capability.

Q: Why does PTVS51VS1UR,115 have a different package (SOD-123W)?

A: PTVS51VS1UR,115 is a Nexperia automotive-qualified part with a 51V standoff voltage. The SOD-123W package is physically smaller than DO-214AC and requires PCB footprint redesign. This part is suitable only when automotive compliance and higher voltage threshold are design requirements.

Q: Are all substitute parts RoHS compliant?

A: Yes. All listed substitute parts maintain ROHS3 compliance status, consistent with the original SMAJ48-E3/5A specification.

Q: What is the temperature range consideration for substitute selection?

A: Most substitutes operate -55°C to 150°C (TJ). SMAJ48A-TP extends to -55°C to 175°C for high-temperature applications. SMA6T56AY operates -40°C to 150°C, which may be limiting in extreme cold environments. Verify thermal requirements against application specifications.

Q: Can higher-current variants (40A) be used in place of the original 4.7A part?

A: Yes, with circuit verification. Higher-current variants (SMA6J48A-TR, SMA6T56AY) provide superior transient suppression and are backward-compatible electrically. However, increased clamping voltage (88.4V to 100V) may affect circuit behavior. Validate against system protection thresholds.

Q: Is packaging interchangeability guaranteed across all DO-214AC substitutes?

A: Yes, for all parts listed with DO-214AC (SMA) package designation. PTVS51VS1UR,115 uses SOD-123W and requires footprint modification. Verify supplier device package designation before procurement.

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