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STMicroelectronics SM6T56CA
- Part No.:
- SM6T56CA
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SM6T56CA.pdf
- Description:
- TVS DIODE 47.6VWM 76.6VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:5,841
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Product details
Overview
SM6T56CA from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode in SMB package, designed for IEC 61000-4-2 ESD protection (30 kV air/contact) and IEC 61000-4-4 surge immunity (4 kV level 4). It features a 56 V breakdown voltage (VBR = 56 V min), 76.6 V clamping voltage (VCL) at 7.8 A (10/1000 µs), 600 W peak pulse power, and operates up to 150 °C junction temperature. It protects signal lines and MOSFET gates in industrial power supplies and telecom interfaces.
For engineers reviewing the SM6T56CA datasheet, SM6T56CA pinout, SM6T56CA application, or SM6T56CA equivalent, this page delivers verified electrical parameters, SMB package layout, bidirectional clamping behavior, thermal derating curves, and direct alternatives with documented VCL, IPP, and leakage differences - critical for robust overvoltage design in high-reliability systems.
Technical Context
The SM6T56CA uses planar silicon junction technology to achieve low leakage (0.2 µA at 25 °C, 1 µA at 85 °C) and stable clamping across its full operating temperature range (–55 to +150 °C). Its bidirectional structure enables symmetrical surge suppression on AC-coupled or differential lines without polarity constraints.
Clamping performance is defined by dynamic resistance (RD = 1.03 Ω at 25 °C), enabling precise VCL calculation via VCL = VBR(max) + RD × IPP. It complies with UL497B (file E136224) as an isolated loop circuit protector and meets IPC7531 footprint standards for reliable PCB mounting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min) | 56 V - Ensures reliable triggering above normal operating voltage of 48 V DC systems |
| VCL @ 7.8 A (10/1000 µs) | 76.6 V - Limits transient voltage to safe level for downstream 80 V-rated ICs |
| IPP (10/1000 µs) | 7.8 A - Supports surge currents typical in 48 V industrial control I/O protection |
| RD (dynamic resistance) | 1.03 Ω - Enables predictable clamping rise with current; critical for precision protection |
| IR (leakage @ VRM) | 0.2 µA @ 25 °C - Minimizes standby power loss in battery-backed or low-power sensor nodes |
| Tj max | 150 °C - Allows operation in enclosed power converters without derating below full rating |
| ESD rating | 30 kV contact/air (IEC 61000-4-2) - Meets highest immunity class for front-panel interfaces |
Pinout & Package
SMB (DO-214AA) surface-mount package: 3.3–3.95 mm length, 5.1–5.6 mm width, 1.9–2.45 mm height; matte tin-plated leads compliant with J-STD-002 E3 and JEDEC MO-136AC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked end) | Anode/Cathode terminal pair | Bidirectional symmetry means both terminals function identically - no polarity assignment required |
| Anode (unmarked end) | Anode/Cathode terminal pair | Enables clamping in both directions; used across differential lines or AC signals without orientation concern |
Key Features
| Feature | Design Value |
|---|---|
| UL497B recognition (E136224) | Validated for isolated loop circuit protection in telecom and industrial safety-critical designs |
| Low Tj-dependent leakage | 1 µA max at 85 °C - Maintains signal integrity in hot environments without false triggering |
| High-temperature power capability | 350 W @ Tj = 150 °C - Sustains surge protection under thermal stress in enclosed power modules |
| Fast response time | < 1 ns - Clamps transients before sensitive gate oxides or logic inputs are damaged |
| MSL Level 1 rating | Unlimited floor life at ≤30 °C/60% RH - Eliminates bake requirements before reflow assembly |
Applications
| Industrial PLC I/O Protection | Telecom Line Interface |
|---|---|
Use Scenario: 24–48 V DC digital input modules exposed to relay coil flyback and field wiring surges. IC Role / Device Role / Timing Role: Bidirectional TVS placed across input terminals to clamp ±1 kV fast transients per IEC 61000-4-4. Use Value: 76.6 V clamping ensures microcontroller GPIOs (rated 80 V abs max) remain within safe operating area during repeated surges. | Use Scenario: RS-485 transceivers connected to outdoor cabling subject to lightning-induced surges. IC Role / Device Role / Timing Role: Placed differentially between A/B lines to suppress common-mode transients while preserving signal integrity. Use Value: Symmetrical clamping prevents DC bias shift on differential bus; 1.03 Ω RD minimizes signal distortion during clamping events. |
| AC-DC Power Supply Feedback Loop | Automotive Body Control Module (BCM) |
Use Scenario: Optocoupler feedback path in isolated 48 V telecom SMPS where leakage must be <1 µA at 85 °C. IC Role / Device Role / Timing Role: Protects opto-LED cathode/anode against coupling from primary-side switching noise. Use Value: 0.2 µA leakage at 25 °C and 1 µA at 85 °C avoids feedback current error that would destabilize regulation. | Use Scenario: LIN bus termination and ESD protection in under-hood BCMs operating at 125 °C ambient. IC Role / Device Role / Timing Role: Bidirectional clamping on LIN data line to meet ISO 10605 (30 kV ESD) and ISO 7637-2 (pulse 1/2a). Use Value: 150 °C Tj max and UL497B certification ensure compliance in automotive safety-critical zones without derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ58CA (Bourns) | VBR = 58–64.4 V; VCL = 93.6 V @ 6.4 A; RD = 1.45 Ω | Higher clamping voltage reduces margin for 80 V-rated devices; lower IPP limits surge handling | Select when higher VBR tolerance is needed to avoid false triggering near 48 V nominal rails |
| P6SMB58CA (ON Semiconductor) | VBR = 58–64.4 V; VCL = 93.6 V @ 6.4 A; IR = 1 µA @ 85 °C | Same clamping penalty; identical leakage but wider VBR tolerance band increases design uncertainty | Prefer only if legacy BOM alignment with P6SMB series is mandatory; otherwise SM6T56CA offers tighter VBR and lower RD |
Compared with SMBJ58CA and P6SMB58CA, SM6T56CA provides 17 V lower clamping voltage at rated current, 0.42 Ω lower dynamic resistance, and ±1 V tighter VBR tolerance - directly improving protection margin and signal fidelity in high-speed or low-voltage-tolerant systems.
Availability
SM6T56CA is available at Aetrix Electronics and suitable for industrial PLC I/O protection, telecom line interface, and automotive body control module designs requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for SM6T56CA 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in power management, analog, MEMS, and microcontrollers for industrial, automotive, and consumer markets.
The SM6T series belongs to ST's high-reliability TVS portfolio, engineered specifically for planar-junction surge protection in space-constrained, high-temperature applications such as industrial power supplies and telecom infrastructure.
FAQ
What is the exact marking code for SM6T56CA on the device body?
The SM6T56CA is marked "NL" on the cathode band end of the SMB package, per STMicroelectronics' official marking table (DS0684 Rev 15, Table 6). This two-character laser mark identifies the 56 V bidirectional variant and distinguishes it from unidirectional SM6T56A ("FL") and other voltage grades.
Does SM6T56CA meet automotive AEC-Q200 requirements?
No - SM6T56CA is not AEC-Q200 qualified. It is rated for industrial temperature range (–55 to +150 °C) and certified to UL497B, IEC 61000-4-2/4-4, and J-STD-020 MSL Level 1, but lacks the extended reliability testing (e.g., temperature cycling, board flex, vibration) required for automotive qualification.
Can SM6T56CA replace SM6T56A in a unidirectional circuit?
No - SM6T56CA is bidirectional and lacks polarity; using it in place of unidirectional SM6T56A may cause unintended conduction in DC-biased circuits. The CA suffix denotes symmetrical clamping, while the A suffix is for single-direction protection. Circuit topology must match device polarity type.
What is the maximum allowable soldering temperature profile for SM6T56CA?
SM6T56CA follows ST's ECOPACK reflow profile: peak temperature 240–245 °C for 60 seconds (max 90 s), ramp-up ≤3 °C/s, ramp-down ≤6 °C/s, and preheat 150–180 °C for 90–120 s. This aligns with IPC/JEDEC J-STD-020 Class 1 requirements and avoids thermal damage to the planar junction.
SM6T56CA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AA, SMB
- Series:
- SM6T, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 47.6V
- Voltage - Breakdown (Min):
- 53.2V
- Voltage - Clamping (Max) @ Ipp:
- 76.6V
- Current - Peak Pulse (10/1000µs):
- 7.8A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
SM6T56CA FAQ
1.How can I place an order for SM6T56CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SM6T56CA 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 SM6T56CA reliable?
The price and inventory of SM6T56CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM6T56CA is usually 5 days.
3.What payment methods are accepted for SM6T56CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM6T56CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM6T56CA?
SM6T56CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM6T56CA 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 SM6T56CA?
For technical support, including SM6T56CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM6T56CA requirements.
6.How does Aetrix verify that SM6T56CA is sourced from the original manufacturer or authorized distributors?
All SM6T56CA 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 SM6T56CA meets industry standards.
7.What is the process for return or replacement of SM6T56CA?
All SM6T56CA units undergo pre-shipment inspection (PSI). If there is an issue with SM6T56CA, 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 SM6T56CA part is unused and in its original packaging.
Return procedure for SM6T56CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM6T56CA Tags
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