Request Quote
(Ships tomorrow)
SMDJ40A Equivalent & Substitute Parts
Part Overview
The SMDJ40A is a unidirectional Zener transient voltage suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose overvoltage protection in surface-mount applications. The device features a 40V reverse standoff voltage, 64.5V maximum clamping voltage, and 46.5A peak pulse current capability in a DO-214AB (SMC) package. The SMDJ40A is currently discontinued at DiGi Electronics. Equivalent and substitute parts are available from multiple manufacturers with identical or comparable electrical specifications, enabling continued design implementation and production continuity.
Substiute Parts
Key Parameters
| Parameter | Value | Unit |
|---|---|---|
| Voltage - Reverse Standoff (Typ) | 40 | V |
| Voltage - Breakdown (Min) | 44.4 | V |
| Voltage - Clamping (Max) @ Ipp | 64.5 | V |
| Current - Peak Pulse (10/1000µs) | 46.5 | A |
| Power - Peak Pulse | 3000 | W |
| Operating Temperature Range | -65 to 150 | °C (TJ) |
| Package / Case | DO-214AB, SMC | — |
| Mounting Type | Surface Mount | — |
| Type | Zener | — |
| Unidirectional Channels | 1 | — |
| RoHS Status | ROHS3 Compliant | — |
| Moisture Sensitivity Level (MSL) | 1 (Unlimited) | — |
Substitute Part Grouping Explanation
Substitution of the SMDJ40A is determined by strict equivalence across the following electrical and mechanical parameters:
- Voltage - Reverse Standoff: 40V (±tolerance)
- Voltage - Breakdown (Min): 44.4V minimum
- Voltage - Clamping (Max) @ Ipp: 64.5V maximum
- Current - Peak Pulse (10/1000µs): 46.5A or greater
- Power - Peak Pulse: 3000W or greater
- Package / Case: DO-214AB (SMC) surface mount
- Operating Temperature Range: -65°C to 150°C or wider
- Type: Unidirectional Zener diode
- RoHS Compliance: ROHS3 Compliant
Substitute parts are grouped into two categories based on peak pulse current and power dissipation capacity:
Category A - Full Electrical Equivalents (46.5A / 3000W): Parts meeting or exceeding all electrical parameters of the original SMDJ40A, including peak pulse current and power dissipation.
Category B - Reduced Current Equivalents (23.2A–32.2A / 1500W): Parts meeting voltage specifications but with reduced peak pulse current and power dissipation. These parts are suitable for applications with lower transient energy requirements.
Parameter Comparison
| Part Number | Manufacturer | Voltage - Reverse Standoff (V) | Voltage - Breakdown Min (V) | Voltage - Clamping Max (V) | Current - Peak Pulse (A) | Power - Peak Pulse (W) | Operating Temp (°C) | Package | Product Status |
|---|---|---|---|---|---|---|---|---|---|
| SMDJ40A | Littelfuse Inc. | 40 | 44.4 | 64.5 | 46.5 | 3000 | -65 to 150 | DO-214AB (SMC) | Discontinued |
| SMDJ40A-HR | Littelfuse Inc. | 40 | 44.4 | 64.5 | 46.5 | 3000 | -65 to 150 | DO-214AB (SMC) | Active |
| SMDJ40A-HRA | Littelfuse Inc. | 40 | 44.4 | 64.5 | 46.5 | 3000 | -65 to 150 | DO-214AB (SMC) | Active |
| SMDJ40A-HRAT7 | Littelfuse | 40 | 44.4 | 64.5 | 46.5 | 3000 | -65 to 150 | DO-214AB (SMC) | Active |
| TPSMD40A | Littelfuse Inc. | 40 | 44.4 | 64.5 | 46.5 | 3000 | -65 to 150 | DO-214AB (SMC) | Active |
| SMDJE40A | Eaton - Electronics Division | 40 | 44.4 | 64.5 | 46.5 | 3000 | -55 to 150 | DO-214AB (SMC) | Active |
| SMLJ40A-TP | Bourns Inc. | 40 | 44.4 | 64.5 | 46.4 | 3000 | -55 to 150 | DO-214AB (SMC) | Active |
| SZ1SMC40AT3G | Littelfuse Inc. | 40 | 44.4 | 64.5 | 32.2 | 1500 | -65 to 150 | DO-214AB (SMC) | Active |
| SMCJ40A | Meritek | 40 | 44.4 | 64.5 | 23.26 | 1500 | -55 to 150 | DO-214AB (SMC) | Active |
| SMCJ40AE3/TR13 | Microchip Technology | 40 | 44.4 | 64.5 | 23.2 | 1500 | -65 to 150 | DO-214AB (SMC) | Active |
Engineering Selection Recommendations
Primary Substitutes (Full Electrical Equivalents):
SMDJ40A-HR, SMDJ40A-HRA, SMDJ40A-HRAT7, and TPSMD40A from Littelfuse Inc. are direct functional equivalents with identical electrical specifications and active product status. These parts maintain the 46.5A peak pulse current and 3000W power dissipation of the original SMDJ40A and are recommended as primary replacements for discontinued inventory.
SMDJE40A (Eaton - Electronics Division) provides full electrical equivalence with 46.5A peak pulse current and 3000W power dissipation. Operating temperature range is -55°C to 150°C, which is narrower than the original part's -65°C to 150°C range.
SMLJ40A-TP (Bourns Inc.) meets all electrical specifications with 46.4A peak pulse current and 3000W power dissipation. Operating temperature range is -55°C to 150°C. REACH status is listed as REACH Affected, which may require compliance verification for specific applications.
Secondary Substitutes (Reduced Current Equivalents):
SZ1SMC40AT3G (Littelfuse Inc.) maintains voltage specifications and operating temperature range (-65°C to 150°C) but provides reduced peak pulse current (32.2A) and power dissipation (1500W). This part is suitable for applications with lower transient energy requirements and carries AEC-Q101 automotive qualification.
SMCJ40A (Meritek) and SMCJ40AE3/TR13 (Microchip Technology) provide voltage equivalence with reduced peak pulse current (23.26A and 23.2A respectively) and 1500W power dissipation. SMCJ40AE3/TR13 maintains the -65°C to 150°C operating temperature range. These parts are suitable for lower-energy transient protection applications.
Compliance Considerations:
All listed substitute parts are ROHS3 Compliant and carry MSL 1 (Unlimited) moisture sensitivity rating. TPSMD40A and SZ1SMC40AT3G carry AEC-Q101 automotive qualification. Selection should account for application-specific compliance requirements and operating temperature constraints.
Frequently Asked Questions (FAQ)
Q: Can SMDJ40A-HR be used as a direct replacement for SMDJ40A?
A: Yes. SMDJ40A-HR is a direct functional equivalent with identical electrical specifications (40V reverse standoff, 64.5V clamping, 46.5A peak pulse current, 3000W power dissipation) and active product status. The part is pin-compatible in DO-214AB (SMC) package configuration.
Q: What is the difference between Category A and Category B substitutes?
A: Category A substitutes (SMDJ40A-HR, SMDJ40A-HRA, SMDJ40A-HRAT7, TPSMD40A, SMDJE40A, SMLJ40A-TP) maintain the full 46.5A peak pulse current and 3000W power dissipation of the original SMDJ40A. Category B substitutes (SZ1SMC40AT3G, SMCJ40A, SMCJ40AE3/TR13) provide reduced peak pulse current (23.2A–32.2A) and 1500W power dissipation. Selection depends on transient energy requirements of the specific application.
Q: Are all substitute parts available in the same package as SMDJ40A?
A: Yes. All listed substitute parts use the DO-214AB (SMC) surface-mount package, ensuring mechanical and footprint compatibility with the original SMDJ40A design.
Q: Does operating temperature range affect part selection?
A: Operating temperature range should be verified against application requirements. SMDJ40A-HR, SMDJ40A-HRA, SMDJ40A-HRAT7, TPSMD40A, SZ1SMC40AT3G, and SMCJ40AE3/TR13 support -65°C to 150°C operation. SMDJE40A, SMLJ40A-TP, and SMCJ40A support -55°C to 150°C operation. Applications requiring -65°C minimum operating temperature should use parts rated to that specification.
Q: Are automotive-qualified alternatives available?
A: Yes. TPSMD40A and SZ1SMC40AT3G carry AEC-Q101 automotive qualification. TPSMD40A provides full electrical equivalence (46.5A, 3000W), while SZ1SMC40AT3G provides reduced current capability (32.2A, 1500W).
Q: What compliance certifications apply to all substitute parts?
A: All listed substitute parts are ROHS3 Compliant and carry MSL 1 (Unlimited) moisture sensitivity rating. REACH status varies by manufacturer and should be verified for specific supply chain requirements.
Alternative Parts
SJ6012L2TP
Littelfuse Inc.
6 Alternative Parts
JMK107BBJ476MA-RE
Taiyo Yuden
10 Alternative Parts
GMK107BBJ475MA-T
Taiyo Yuden
5 Alternative Parts
SJ6020N2ARP
Littelfuse Inc.
3 Alternative Parts
SJ6025R2ATP
Littelfuse Inc.
4 Alternative Parts
2474-05L
API Delevan Inc.
1 Alternative Parts
4590R-684K
API Delevan Inc.
1 Alternative Parts
CM6560R-334
API Delevan Inc.
1 Alternative Parts
CM6460-104
API Delevan Inc.
1 Alternative Parts
5526-12
API Delevan Inc.
1 Alternative Parts