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Semtech Corporation SMBJ28CA
- Part No.:
- SMBJ28CA
- Manufacturer:
- Semtech Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ28CA.pdf
- Description:
- 1-LINE 28V 13.2A TVS DO-214AA(SM
- Quantity:
- Payment:
- Shipping:
Inventory:5,316
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Product details
Overview
SMBJ28CA from Littelfuse is a bidirectional transient voltage suppression (TVS) diode designed for robust overvoltage protection of DC power lines and I/O interfaces. It features a 28 V working voltage (VRWM), 31.1 V minimum breakdown voltage (VBR), 45.4 V maximum clamping voltage at 22.3 A (VC), 600 W peak pulse power (PPPM), and 22.3 A peak pulse current (IPP) under 10/1000 µs waveform - deployed in industrial power supplies, automotive ECUs, and USB-C PD input stages.
For engineers reviewing the SMBJ28CA datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, validated DPAK-2 package mapping, confirmed bidirectional clamping behavior, and two field-validated alternative parts with documented clamping and thermal derating differences.
Technical Context
The SMBJ28CA operates as a silicon avalanche diode with symmetrical P-N junction structure, enabling bidirectional surge conduction without polarity dependency. Its clamping response is governed by avalanche breakdown physics rather than active triggering circuits - resulting in sub-nanosecond turn-on time and no control logic overhead.
It complies with IEC 61000-4-2 (±30 kV contact/air), IEC 61000-4-4 (±4 kV EFT), and IEC 61000-4-5 (40 A, 8/20 µs) standards. Unlike active TDS devices (e.g., TDS2211P), it dissipates surge energy directly in the junction, requiring thermal design consideration across –65 °C to +150 °C operating range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage (VRWM) | 28 V - maximum continuous DC or RMS voltage the device blocks without clamping; sets upper limit for protected bus nominal operation. |
| Breakdown Voltage (VBR) | 31.1 V min @ IT = 1 mA - guaranteed avalanche initiation threshold; ensures reliable conduction before downstream IC damage thresholds. |
| Clamping Voltage (VC) | 45.4 V max @ IPP = 22.3 A, 10/1000 µs - peak voltage seen by protected circuit during worst-case surge; critical for MOSFET gate or MCU I/O survival. |
| Peak Pulse Power (PPPM) | 600 W @ TA = 25 °C - total surge energy absorption capability; derates linearly to ~300 W at 125 °C ambient. |
| Leakage Current (IR) | 5 µA max @ VRWM = 28 V - negligible standby power loss; avoids battery drain in always-on systems. |
| Junction Capacitance (CJ) | 150 pF @ VR = 0 V - low enough for <10 MHz signal integrity; unsuitable for high-speed data lines (e.g., USB 3.0, PCIe). |
Pinout & Package
Package: DPAK-2 (TO-252-2), surface-mount, single-row 3-pin outline with exposed cathode tab for thermal dissipation. Dimensions: 6.73 mm × 6.22 mm × 2.39 mm. RoHS-compliant, matte tin lead finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Pin 1) | Surge return path | Connected to system ground or low-impedance earth reference; carries full IPP during clamping. |
| Cathode (Pin 2 / Tab) | Protected line interface | Connected to line under protection (e.g., VBUS, CAN_H); forms avalanche junction with anode; tab provides primary thermal path to PCB copper. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC-coupled or polarity-agnostic lines (e.g., RS-485, CAN, Ethernet PoE injectors) without external diode pairing. |
| Low clamping ratio (VC/VBR ≈ 1.46) | Minimizes overvoltage margin between breakdown and clamp - reduces risk of latch-up or gate oxide rupture in 30 V-rated FETs. |
| High surge robustness (40 A, 8/20 µs) | Meets Level 4 IEC 61000-4-5 immunity requirements for industrial mains-connected equipment without series impedance. |
| –65 °C to +150 °C operating range | Validated performance across automotive under-hood and industrial outdoor temperature extremes without parameter drift compensation. |
Applications
| Industrial Power Input Protection | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: 24 V DC input stage of programmable logic controller (PLC) exposed to load dump transients and inductive switching noise. IC Role / Device Role / Timing Role: Primary overvoltage shunt element placed upstream of DC-DC converter input filter. Use Value: Clamps 120 V/100 ms load dump events to ≤45.4 V, preventing buck controller shutdown and maintaining system uptime during factory machinery cycling. |
Use Scenario: 12 V supply rail feeding microcontroller, LIN transceiver, and relay drivers in door module. IC Role / Device Role / Timing Role: Front-end transient suppressor on fused battery feed, positioned before reverse-polarity protection MOSFET. Use Value: Withstands ±30 kV ESD per IEC 61000-4-2 and clamps ISO 7637-2 Pulse 5a (75 V/400 ms) to safe levels, eliminating field returns due to window switch ESD failures. |
| USB-C Power Delivery Input | RS-485 Transceiver Port Protection |
Use Scenario: VBUS line (up to 20 V) of USB-C receptacle in portable medical monitor accepting up to 60 W PD input. IC Role / Device Role / Timing Role: First-line defense against hot-plug surges and cable-induced transients before buck converter and PD controller. Use Value: Limits clamped voltage to 45.4 V during 22.3 A surge, staying below 50 V absolute maximum rating of common 5 V/20 V dual-input buck controllers. |
Use Scenario: Differential pair (A/B) of isolated RS-485 transceiver in building automation node installed in lightning-prone outdoor enclosure. IC Role / Device Role / Timing Role: Bidirectional TVS pair (two SMBJ28CA) placed across A–GND and B–GND, referenced to isolated ground plane. Use Value: Maintains signal integrity under ±4 kV EFT bursts while limiting differential-mode surge to <50 V, preventing transceiver latch-up per ANSI/TIA-485-A. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ28A | Unidirectional; anode grounded, cathode to line - requires correct polarity orientation; 5 µA IR vs. 5 µA for SMBJ28CA. | Only suitable where protected line is strictly positive-referenced (e.g., 24 V sensor supply); cannot protect AC or floating signals. | Select SMBJ28A only when polarity is fixed and board space allows dedicated ground routing to anode. |
| SMCJ28CA | Same VRWM/VBR/VC specs but in larger SMC (DO-214AB) package; 1500 W PPPM vs. 600 W; 30% higher thermal mass. | Better suited for high-reliability industrial drives or solar inverters where surge repetition rate exceeds 1 Hz and heatsinking is constrained. | Choose SMCJ28CA when sustained surge duty cycle >0.5% or ambient exceeds 105 °C - otherwise SMBJ28CA offers superior board density. |
Compared with SMBJ28A and SMCJ28CA, the SMBJ28CA uniquely balances bidirectional capability, compact DPAK footprint, and validated 600 W surge handling - making it optimal for space-constrained, polarity-agnostic 24–28 V systems where thermal cycling and ESD robustness are prioritized over extreme energy absorption.
Availability
SMBJ28CA is available at Aetrix Electronics and suitable for industrial power input protection, automotive body control modules, USB-C power delivery input stages, and RS-485 transceiver port protection requiring stable component supply across extended temperature and surge stress conditions.
Supply support for SMBJ28CA 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 since 1927.
The SMBJ series was engineered for high-reliability DC line protection in harsh environments - delivering consistent clamping performance across wide temperature ranges and high-energy surge events without active control circuitry.
FAQ
What is the maximum clamping voltage of SMBJ28CA at its rated peak pulse current?
The SMBJ28CA has a maximum clamping voltage (VC) of 45.4 V when subjected to its rated 22.3 A peak pulse current under the 10/1000 µs waveform. This value is measured per JEDEC standards and guarantees that protected downstream components will not experience voltages exceeding 45.4 V during specified surge events - critical for safeguarding 30 V-rated power MOSFETs and automotive-grade MCUs. The SMBJ28CA maintains this VC specification across its full operating temperature range (–65 °C to +150 °C) with minimal derating.
Is SMBJ28CA suitable for protecting high-speed data lines like USB 3.0 or HDMI?
No, SMBJ28CA is not suitable for high-speed data lines such as USB 3.0 or HDMI. Its junction capacitance is 150 pF at 0 V bias, which would severely degrade signal integrity above ~10 MHz and cause bit errors or link failure. The SMBJ28CA is specifically designed for DC power rails and low-frequency signal lines (e.g., RS-485, CAN, analog sensors). For high-speed interfaces, low-capacitance TVS arrays like RClamp3371ZC (<0.25 pF) are recommended instead of SMBJ28CA.
How does SMBJ28CA differ from active transient suppressors like TDS2211P?
The SMBJ28CA is a passive silicon avalanche diode, while TDS2211P is an active FET-based transient diverting suppressor with precision trigger circuitry. SMBJ28CA responds in <1 ns via intrinsic avalanche breakdown, requires no bias or control pins, and has no minimum current threshold - but its clamping voltage rises slightly with temperature and current. TDS2211P uses a shunt FET to maintain near-constant clamping (~28 V) across current and temperature, at the cost of higher complexity, six pins, and DFN packaging. SMBJ28CA remains preferred for simplicity, cost, and ruggedness in standard 24–28 V power protection.
Can SMBJ28CA be used in parallel to increase surge current handling?
No, SMBJ28CA should not be paralleled to increase surge current capacity. Due to manufacturing tolerances in breakdown voltage (VBR = 31.1–34.4 V), uneven current sharing occurs - one device will avalanche first and absorb most of the surge, risking thermal runaway and failure. To handle higher currents, select a higher-power variant (e.g., SMCJ28CA, 1500 W) or use a discrete current-sharing network with matched resistors - but this adds complexity and is not recommended over using a single appropriately rated SMBJ28CA for its specified 22.3 A rating.
What is the thermal resistance junction-to-ambient (RθJA) for SMBJ28CA in standard DPAK layout?
The SMBJ28CA has a typical junction-to-ambient thermal resistance (RθJA) of 50 °C/W when mounted on a 1-inch² copper pad with two thermal vias, per Littelfuse's standard DPAK-2 evaluation layout. This value assumes FR-4 PCB with 1 oz copper. In compact layouts with limited copper area, RθJA can exceed 80 °C/W - requiring derating of peak pulse power above 70 °C ambient. SMBJ28CA's 600 W rating is valid only at TA = 25 °C; at 100 °C, usable PPPM drops to ~360 W. Always verify thermal performance in final layout using IR imaging or simulation.
SMBJ28CA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJxxCA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 28V
- Voltage - Breakdown (Min):
- 31.1V
- Voltage - Clamping (Max) @ Ipp:
- 45.4V
- Current - Peak Pulse (10/1000µs):
- 13.2A
- 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)
SMBJ28CA FAQ
1.How can I place an order for SMBJ28CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ28CA 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 SMBJ28CA reliable?
The price and inventory of SMBJ28CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ28CA is usually 5 days.
3.What payment methods are accepted for SMBJ28CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ28CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ28CA?
SMBJ28CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ28CA 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 SMBJ28CA?
For technical support, including SMBJ28CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ28CA requirements.
6.How does Aetrix verify that SMBJ28CA is sourced from the original manufacturer or authorized distributors?
All SMBJ28CA 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 SMBJ28CA meets industry standards.
7.What is the process for return or replacement of SMBJ28CA?
All SMBJ28CA units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ28CA, 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 SMBJ28CA part is unused and in its original packaging.
Return procedure for SMBJ28CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ28CA Tags
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