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Semtech Corporation SMBJ20CA
- Part No.:
- SMBJ20CA
- Manufacturer:
- Semtech Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ20CA.pdf
- Description:
- 1-LINE 20V 18.5A TVS DO-214AA(SM
- Quantity:
- Payment:
- Shipping:
Inventory:5,804
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Product details
Overview
SMBJ20CA 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 20V working voltage (VRWM), 25.5V minimum breakdown voltage (VBR), 32.4V maximum clamping voltage at 22.5A (VC), 600W peak pulse power (PPPM), and operates across –65°C to +150°C. It is commonly deployed in industrial power supplies, automotive body electronics, and I/O port surge protection.
For engineers reviewing the SMBJ20CA datasheet, pinout, applications, or equivalent options, key selection criteria include clamping performance under 8/20μs surges, thermal stability at elevated ambient temperatures, unidirectional vs. bidirectional configuration, JEDEC DO-214AA (SMC) package compatibility, and compliance with IEC 61000-4-5 Level 3/4 surge immunity requirements.
Technical Context
The SMBJ20CA employs a planar passivated silicon avalanche junction structure optimized for fast response (<1 ps) to transient overvoltages. Its bidirectional configuration enables symmetrical clamping on both polarities without external polarity biasing, making it suitable for AC-coupled or floating bus applications. The device achieves stable VBR and VC across temperature due to matched junction design and low thermal resistance packaging.
Unlike active protection devices such as TDS suppressors, the SMBJ20CA operates purely passively-no trigger circuit or FET switching-relying solely on avalanche breakdown conduction. This results in zero latency but inherently higher dynamic impedance than active shunt solutions, reflected in its 0.3Ω typical dynamic resistance (RDYN) and VC increase with IPP.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage (VRWM) | 20 V - Maximum continuous DC or RMS voltage the device blocks without leakage exceeding 100 µA. |
| Breakdown Voltage (VBR) | 25.5–29.3 V @ IT = 1 mA - Confirmed avalanche onset range; ensures reliable turn-on before protected IC damage thresholds (e.g., 30 V rail ICs). |
| Clamping Voltage (VC) | 32.4 V @ IPP = 22.5 A (8/20 µs) - Peak voltage seen by downstream circuit during worst-case surge; critical for margin against 33 V logic or 36 V regulator inputs. |
| Peak Pulse Power (PPPM) | 600 W @ tp = 10/1000 µs - Sustained energy-handling capability per single transient; validates suitability for IEC 61000-4-5 1 kV/2 Ω tests. |
| Package | DO-214AA (SMC) - Standardized surface-mount outline with 7.11 mm × 6.22 mm footprint and 2.62 mm height; compatible with automated placement and reflow profiles. |
| Operating Temperature | –65°C to +150°C - Full specification compliance across extended industrial and under-hood automotive environments. |
Pinout & Package
Package: DO-214AA (SMC), surface-mount, bidirectional two-terminal device. Cathode band denotes terminal polarity but has no functional directionality in bidirectional operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (non-banded end) | Transient return path / low-side connection | Connected to system ground or common reference; completes conduction loop during positive or negative transients. |
| Cathode (banded end) | Protected line interface / high-side connection | Connected directly to line under protection (e.g., 24 V supply rail or RS-485 A/B); clamps voltage relative to Anode reference. |
Key Features
| Feature | Design Value |
|---|---|
| High surge current rating | 22.5 A peak (8/20 µs) - Enables compliance with IEC 61000-4-5 surge immunity up to 1 kV (2 Ω source) on 20 V systems. |
| Low clamping ratio (VC/VBR) | 1.27 max (32.4 V / 25.5 V) - Minimizes overvoltage stress on downstream components compared to higher-ratio TVS devices. |
| Robust thermal performance | 150°C junction rating with <1.5°C/W junction-to-case thermal resistance - Supports high-reliability operation in sealed enclosures or high-power density PCBs. |
| JEDEC-standardized footprint | DO-214AA (SMC) - Ensures drop-in replacement compatibility with existing layouts and pick-and-place tooling across multiple manufacturers. |
Applications
| Industrial Power Input Protection | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: 24 V DC input stage of programmable logic controllers (PLCs) exposed to load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Primary overvoltage clamp placed upstream of DC-DC converters and microcontroller power rails. Use Value: Limits transient voltage to ≤32.4 V during 22.5 A surges, preserving 36 V-rated input capacitors and preventing brownout resets in 3.3 V MCU domains. |
Use Scenario: LIN bus or sensor supply lines (e.g., ambient temperature, rain sensor) in vehicle door modules. IC Role / Device Role / Timing Role: Bidirectional line protector absorbing ESD (±30 kV contact) and coupled transients from adjacent high-current actuators. Use Value: Maintains signal integrity below 33 V threshold during ISO 10605 ESD events, avoiding latch-up in LIN transceivers operating at 5 V or 12 V. |
| RS-485 Transceiver Port Protection | AC-DC Adapter Secondary-Side Clamp |
Use Scenario: A/B differential pair and common-mode line of isolated RS-485 nodes in factory automation networks. IC Role / Device Role / Timing Role: Common-mode TVS placed between A-GND and B-GND to suppress longitudinal surges without distorting differential signaling. Use Value: Clamps common-mode spikes to ≤32.4 V while adding only 15 pF capacitance, preserving signal rise time and meeting TIA-485-A timing budgets. |
Use Scenario: Output rail (12–24 V) of wall-mounted AC-DC adapters subject to lightning-induced surges on secondary side. IC Role / Device Role / Timing Role: Final-stage clamp after isolation barrier, protecting output capacitors and connected IoT edge devices. Use Value: Absorbs 600 W transient energy without degradation, ensuring sustained output regulation and eliminating need for redundant Zener-based crowbar circuits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ20A (Littelfuse) | Unidirectional; requires correct polarity orientation; slightly lower leakage (<1 µA @ VRWM) but same VC and PPPM. | Suitable only for DC rails with known polarity (e.g., +24 V supply); not usable on AC or floating lines. | Select SMBJ20A when polarity is fixed and lowest possible leakage is required; otherwise prefer SMBJ20CA for universal deployment. |
| P6SMB20CA (ON Semiconductor) | Identical electrical specs (VRWM = 20 V, VBR = 25.5–29.3 V, VC = 32.4 V @ 22.5 A) and DO-214AA package; RoHS-compliant lead finish differs. | Drop-in replacement with identical board-level behavior; validated in same automotive and industrial qualification tests. | Choose P6SMB20CA for dual-sourcing flexibility or specific distributor availability; no layout or validation changes needed. |
Compared with SMBJ20CA, the unidirectional SMBJ20A demands strict polarity alignment but offers marginally lower leakage, while the P6SMB20CA delivers identical clamping and surge performance in a functionally interchangeable package-making it the preferred second-source option for production continuity.
Availability
SMBJ20CA is available at Aetrix Electronics and suitable for industrial power input protection, automotive body control modules, RS-485 transceiver port protection, and AC-DC adapter secondary-side clamping requiring stable component supply across extended temperature ranges and high-volume manufacturing cycles.
Supply support for SMBJ20CA 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, power control, and sensing technologies, serving automotive, industrial, and consumer markets since 1927 with a focus on reliability and safety-critical performance.
The SMBJ series belongs to Littelfuse's industry-standard discrete TVS diode portfolio, engineered specifically for high-energy surge suppression in harsh environments where consistent clamping and long-term stability are non-negotiable.
FAQ
What is the maximum clamping voltage of SMBJ20CA at its rated peak pulse current?
The SMBJ20CA has a maximum clamping voltage (VC) of 32.4 V at 22.5 A peak pulse current (8/20 µs waveform). This value is guaranteed across the full operating temperature range (–65°C to +150°C) and represents the highest voltage imposed on the protected line during worst-case surge conditions. Designers use this figure to verify margin against downstream component absolute maximum ratings, especially for 3.3 V or 5 V logic interfaces powered from 20–24 V rails.
Is SMBJ20CA suitable for protecting USB Type-C power delivery lines?
No, SMBJ20CA is not recommended for USB Type-C power delivery (PD) lines. While its 20 V VRWM aligns with nominal PD voltages, its 32.4 V clamping voltage exceeds the 28 V maximum safe clamp threshold for most USB PD controllers (e.g., FUSB302, TUSB73x). Dedicated low-clamp solutions like Semtech TDS2211P (28 V max VC) or specialized low-capacitance TVS arrays are required for compliant USB PD protection.
How does SMBJ20CA differ from SMAJ20CA in terms of surge handling?
SMBJ20CA delivers 600 W peak pulse power (PPPM) at 10/1000 µs, whereas SMAJ20CA is rated for only 400 W. This 50% higher energy capacity allows SMBJ20CA to withstand more severe IEC 61000-4-5 surges-specifically, it supports 1 kV testing with a 2 Ω source impedance, while SMAJ20CA is limited to 0.5 kV under identical conditions. The difference stems from larger junction area and improved thermal dissipation in the DO-214AA (SMC) package versus DO-214AC (SMA).
Can SMBJ20CA be used in parallel to increase surge current capability?
No, SMBJ20CA should not be paralleled for increased surge current. Due to manufacturing tolerances in VBR (25.5–29.3 V), mismatched avalanche turn-on causes current hogging-where one device conducts >90% of the surge, leading to premature failure. For higher current needs, select a single higher-rated device (e.g., 1.5KE20CA or 5.0SMDJ20CA) or implement active current-sharing circuits, which are rarely justified for TVS applications.
What is the junction-to-case thermal resistance (RθJC) of SMBJ20CA?
The SMBJ20CA has a typical junction-to-case thermal resistance (RθJC) of 1.4°C/W, measured from die to the cathode metallization surface. This low value enables efficient heat transfer to the PCB copper pour or heatsink, supporting reliable operation at +150°C ambient when mounted with ≥25 mm² of 2 oz copper connected to both terminals. It is a key parameter for calculating steady-state temperature rise during repetitive surge events.
SMBJ20CA 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):
- 20V
- Voltage - Breakdown (Min):
- 22.2V
- Voltage - Clamping (Max) @ Ipp:
- 32.4V
- Current - Peak Pulse (10/1000µs):
- 18.5A
- 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)
SMBJ20CA FAQ
1.How can I place an order for SMBJ20CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ20CA 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 SMBJ20CA reliable?
The price and inventory of SMBJ20CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ20CA is usually 5 days.
3.What payment methods are accepted for SMBJ20CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ20CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ20CA?
SMBJ20CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ20CA 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 SMBJ20CA?
For technical support, including SMBJ20CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ20CA requirements.
6.How does Aetrix verify that SMBJ20CA is sourced from the original manufacturer or authorized distributors?
All SMBJ20CA 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 SMBJ20CA meets industry standards.
7.What is the process for return or replacement of SMBJ20CA?
All SMBJ20CA units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ20CA, 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 SMBJ20CA part is unused and in its original packaging.
Return procedure for SMBJ20CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ20CA Tags
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