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Semtech Corporation SMBJ48CA
- Part No.:
- SMBJ48CA
- Manufacturer:
- Semtech Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ48CA.pdf
- Description:
- 1-LINE 48V 7.7A TVS DO-214AA(SMB
- Quantity:
- Payment:
- Shipping:
Inventory:9,775
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Product details
Overview
SMBJ48CA from Littelfuse is a bidirectional transient voltage suppression (TVS) diode designed for robust overvoltage protection of DC power lines and low-speed signal lines. It features a 48 V working voltage (VRWM), 53.3 V minimum breakdown voltage (VBR), 77.4 V maximum clamping voltage (VC) at 12.3 A peak pulse current (IPP), and 600 W peak pulse power (PPK) per IEC 61000-4-5 (8/20 µs). It is commonly deployed in industrial power supplies, automotive body electronics, and PoE-powered equipment.
For engineers reviewing the SMBJ48CA datasheet, pinout, applications, or equivalent options, key selection considerations include its unidirectional/bidirectional configuration, clamping performance under temperature variation, JEDEC DO-214AA (SMC) package thermal derating, and compatibility with 48 V nominal bus architectures requiring ±30 kV ESD immunity per IEC 61000-4-2.
Technical Context
The SMBJ48CA operates as a silicon avalanche diode with symmetrical bidirectional clamping behavior, enabling protection of AC-coupled or floating DC lines without polarity constraints. Its junction structure delivers stable reverse standoff and breakdown characteristics across –65 °C to +150 °C operating temperature range, with leakage current ≤5 µA at VRWM and <1 mA at VBR.
Clamping response is governed by avalanche multiplication dynamics rather than active circuitry - unlike FET-based suppressors such as Semtech TDS2211P - resulting in predictable but temperature-dependent VC rise (typically +0.1 V/°C above 25 °C). It complies with IEC 61000-4-2 (ESD), IEC 61000-4-4 (EFT), and IEC 61000-4-5 (surge) standards when applied with appropriate PCB layout and series impedance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage (VRWM) | 48 V - maximum continuous DC or RMS voltage the device blocks without conduction. |
| Breakdown Voltage (VBR) | 53.3 V min @ 1 mA - guaranteed avalanche initiation threshold, defining minimum protection trigger level. |
| Clamping Voltage (VC) | 77.4 V max @ IPP = 12.3 A (8/20 µs) - peak line voltage seen by protected IC during worst-case surge. |
| Peak Pulse Power (PPK) | 600 W @ 8/20 µs - energy-handling capability for short-duration transients; derates linearly above 25 °C. |
| Leakage Current (IR) | ≤5 µA @ VRWM = 48 V - negligible standby power loss and minimal impact on high-impedance sensing circuits. |
| Package | DO-214AA (SMC) - industry-standard surface-mount outline with 7.11 mm × 6.22 mm footprint and 2.62 mm height; supports automated placement and reflow. |
Pinout & Package
Package: DO-214AA (SMC), single-body bidirectional TVS diode with cathode band marking. No discrete pins - anode and cathode terminals are defined by molded cathode band on one end of the SMC body.
| Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode Band End | Common reference terminal for bidirectional clamping | Marked end serves as both anode (for negative transients) and cathode (for positive transients); no polarity-specific routing required. |
| Opposite End | Common reference terminal for bidirectional clamping | Unmarked end completes the symmetrical junction; both ends function identically in AC or floating DC applications. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables protection of AC lines, RS-485 buses, or isolated DC rails without polarity assignment or external diode pairing. |
| IEC 61000-4-2 ESD rating | ±30 kV contact / ±30 kV air - exceeds Level 4 immunity requirements for industrial and automotive interfaces. |
| JEDEC DO-214AA footprint | Ensures drop-in compatibility with legacy SMC-based designs and broad availability across assembly houses and test fixtures. |
| Low clamping ratio (VC/VBR) | 1.45 typical - tight voltage margin between breakdown and clamping improves system-level surge margin versus higher-ratio alternatives. |
| RoHS-compliant, halogen-free | Meets IPC-1752A material declaration requirements and supports lead-free reflow profiles up to 260 °C. |
Applications
| Industrial Power Input Protection | Automotive Body Control Module (BCM) Supply |
|---|---|
|
Use Scenario: 48 V DC input stage of programmable logic controllers (PLCs) exposed to load dump and inductive switching transients. IC Role / Device Role / Timing Role: Primary overvoltage clamp placed upstream of DC-DC converters and microcontroller power rails. Use Value: Limits transient excursions to ≤77.4 V, preventing damage to 60 V-rated input capacitors and 5 V/3.3 V regulator ICs downstream. |
Use Scenario: 48 V battery-fed lighting and window lift modules subject to ISO 7637-2 Pulse 1, 2a, and 5a. IC Role / Device Role / Timing Role: Standalone surge suppressor mounted at connector interface before local LDO regulators. Use Value: Withstands 12.3 A surges while maintaining clamping below BCM ASIC absolute maximum ratings (typically 80 V). |
| PoE-Powered Equipment (IEEE 802.3bt) | RS-485/422 Data Line Protection |
|
Use Scenario: Class 5/6 (60 W / 90 W) powered devices receiving 52–57 V DC via Ethernet cabling. IC Role / Device Role / Timing Role: Secondary overvoltage guard after primary PoE interface IC, protecting DC-DC controller inputs. Use Value: Clamps lightning-induced surges on PSE side without false triggering during normal 57 V operation or startup inrush. |
Use Scenario: Two-wire differential bus in factory automation networks operating at ≤10 Mbps with long cable runs. IC Role / Device Role / Timing Role: Common-mode TVS across A/B lines referenced to local ground, complementing differential receivers. Use Value: Bidirectional symmetry ensures equal protection against positive/negative ESD events on either line, preserving signal integrity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ48A | Unidirectional version - requires explicit polarity assignment; same VRWM, VBR, VC, and PPK ratings. | Suitable only for DC lines with known, fixed polarity (e.g., +48 V supply rail with grounded return). | Select SMBJ48A only when polarity is guaranteed and board space allows dedicated anode/cathode routing. |
| SAC48 | Surface-mount ceramic varistor (MLV); 48 V nominal voltage, 100 J energy rating, higher capacitance (~300 pF). | Better for high-energy, low-frequency surges (e.g., AC mains coupling); unsuitable for high-speed data lines due to capacitance. | Prefer SAC48 where surge repetition rate is low and clamping voltage stability over temperature is less critical than energy absorption. |
Compared with SMBJ48A and SAC48, the SMBJ48CA offers polarity-agnostic protection with superior clamping consistency and lower parasitic capacitance (<15 pF), making it optimal for mixed-signal 48 V systems where both power and communication lines share common grounding schemes.
Availability
SMBJ48CA is available at Aetrix Electronics and suitable for industrial power input protection, automotive BCM supply conditioning, and PoE-powered equipment requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for SMBJ48CA includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Littelfuse is a global leader in circuit protection, specializing in fuses, TVS diodes, MOVs, and gas discharge tubes for industrial, automotive, and consumer markets.
The SMBJ series belongs to Littelfuse's high-power surface-mount TVS portfolio, engineered specifically for robust 40–60 V DC system protection with emphasis on repeatable clamping, JEDEC-standard packaging, and AEC-Q200 stress qualification readiness.
FAQ
What is the maximum clamping voltage of SMBJ48CA under IEC 61000-4-5 surge conditions?
The SMBJ48CA has a maximum clamping voltage (VC) of 77.4 V when subjected to a 12.3 A peak pulse current with an 8/20 µs waveform per IEC 61000-4-5. This value is measured across the device terminals and represents the worst-case voltage imposed on downstream circuitry during standardized surge testing. The SMBJ48CA maintains this clamping performance across its full operating temperature range, with minor positive drift (<0.1 V/°C) above 25 °C.
Is SMBJ48CA suitable for protecting RS-485 communication lines?
Yes, SMBJ48CA is suitable for RS-485 line protection when applied in common-mode configuration across A/B lines referenced to local ground. Its bidirectional nature ensures equal clamping for both polarities, and its low capacitance (<15 pF) minimizes signal distortion at data rates up to 10 Mbps. However, for full-duplex or high-speed (>20 Mbps) implementations, additional low-capacitance TVS devices like RClamp3371ZC may be layered alongside SMBJ48CA to address differential-mode transients.
How does SMBJ48CA differ from unidirectional SMBJ48A?
The SMBJ48CA is bidirectional, meaning it clamps symmetrically for both positive and negative transients, while SMBJ48A is unidirectional and conducts only for positive excursions relative to its cathode. This makes SMBJ48CA ideal for AC-coupled or floating DC applications (e.g., RS-485, PoE pairs), whereas SMBJ48A is restricted to fixed-polarity DC rails. Both share identical VRWM (48 V), VBR (53.3 V min), VC (77.4 V max), and PPK (600 W) specifications.
What is the operating temperature range for SMBJ48CA?
The SMBJ48CA is rated for operation from –65 °C to +150 °C, with electrical parameters guaranteed over the full industrial range of –40 °C to +125 °C. Its leakage current remains ≤5 µA at VRWM across this range, and clamping voltage increases predictably with temperature at approximately +0.1 V/°C above 25 °C. Derating of peak pulse power begins at +25 °C per the published thermal resistance curve in the SMBJ48CA datasheet.
Can SMBJ48CA be used in automotive applications?
Yes, SMBJ48CA is widely used in automotive body electronics including lighting control, window lift, and HVAC modules supplied from 48 V battery systems. While not AEC-Q200 qualified out-of-box, its construction and performance align with ISO 7637-2 Pulse 1, 2a, and 5a requirements. For production automotive use, Littelfuse offers AEC-Q200-qualified variants such as the A-SMBJ48CA, which undergoes additional stress screening and lot traceability - the SMBJ48CA itself serves as the baseline design for those qualified versions.
SMBJ48CA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 48V
- Voltage - Breakdown (Min):
- 53.3V
- Voltage - Clamping (Max) @ Ipp:
- 77.4V
- Current - Peak Pulse (10/1000µs):
- 7.7A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMB)
SMBJ48CA FAQ
1.How can I place an order for SMBJ48CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ48CA on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SMBJ48CA reliable?
The price and inventory of SMBJ48CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ48CA is usually 5 days.
3.What payment methods are accepted for SMBJ48CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ48CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ48CA?
SMBJ48CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ48CA order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SMBJ48CA?
For technical support, including SMBJ48CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ48CA requirements.
6.How does Aetrix verify that SMBJ48CA is sourced from the original manufacturer or authorized distributors?
All SMBJ48CA products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SMBJ48CA meets industry standards.
7.What is the process for return or replacement of SMBJ48CA?
All SMBJ48CA units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ48CA, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SMBJ48CA part is unused and in its original packaging.
Return procedure for SMBJ48CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ48CA Tags
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