My Inquiry
My Account
STMicroelectronics SMBJ8.5A-TR
- Part No.:
- SMBJ8.5A-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ8.5A-TR.pdf
- Description:
- TVS DIODE 8.5VWM 14.4VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:4,202
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMBJ8.5A-TR from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode designed for primary-level surge protection on DC power rails and signal lines. It features a 8.5 V standoff voltage (VRM), 9.4 V minimum breakdown voltage (VBR), 14.4 V clamping voltage (VCL) at 41.7 A peak pulse current (IPP), and 600 W peak pulse power rating (10/1000 µs). It is used in industrial power supplies, automotive body control modules, and PoE-powered devices to suppress ESD and inductive switching transients.
For engineers reviewing the SMBJ8.5A-TR datasheet, SMBJ8.5A-TR pinout, SMBJ8.5A-TR application, or SMBJ8.5A-TR equivalent, key selection criteria include clamping voltage margin relative to protected IC VMAX, leakage current at operating temperature, junction temperature derating above 25 °C, and UL497B recognition for isolated loop circuit protection.
Technical Context
This TVS diode operates as a voltage-clamped shunt protector: under normal bias it presents <1 µA leakage up to 8.5 V; when transient voltage exceeds 9.4 V, it avalanches rapidly (<1 ns response) to clamp the line at ≤14.4 V while diverting up to 41.7 A (10/1000 µs). Its planar silicon junction enables stable performance across –55 °C to +150 °C junction temperature range.
The device complies with IEC 61000-4-2 (±30 kV contact/air discharge) and IEC 61000-4-4 (4 kV level 4), and is UL497B-recognized (file E136224) for use in isolated loop circuits. Its SMB package supports IPC7531-compliant footprint and JEDEC-registered outline, with matte tin-plated leads meeting J-STD-002 solderability and JESD-201 Class 2 whisker resistance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 8.5 V - Maximum continuous reverse operating voltage before significant leakage begins. |
| Breakdown Voltage (VBR) | 9.4–9.9 V @ 1 mA - Confirmed avalanche initiation threshold; ensures reliable triggering before downstream IC damage. |
| Clamping Voltage (VCL) | 14.4 V @ 41.7 A (10/1000 µs) - Peak voltage seen by protected circuit during worst-case surge; defines safe margin vs. IC absolute max rating. |
| Peak Pulse Power (PPP) | 600 W (10/1000 µs) - Sustained energy-handling capability at 25 °C; derates to 350 W at Tj = 150 °C per Figure 3. |
| Leakage Current (IRM) | 1 µA @ 85 °C - Low leakage preserves efficiency in battery-backed or low-power sensor nodes. |
| Junction Temperature Range | –55 °C to +150 °C - Enables deployment in under-hood automotive, industrial motor drives, and high-ambient SMPS. |
| UL Recognition | UL497B (File E136224) - Certified for use in isolated loop circuits, supporting safety-critical telecom and process control interfaces. |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, 2-terminal device with cathode band marking. Dimensions: 3.30–3.95 mm length × 5.10–5.60 mm width × 2.45 mm height (JEDEC MS-012AC).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lowest potential node; establishes reference for clamping action. |
| Cathode | Protected line input | Connected to line being protected (e.g., 12 V rail); conducts surge current to anode during overvoltage event. |
Key Features
| Feature | Design Value |
|---|---|
| IEC 61000-4-2 ESD robustness | ±30 kV air/contact discharge - Eliminates need for external ESD diodes in USB, RS-485, and CAN bus front-ends. |
| Low dynamic resistance (RD) | 0.096 Ω - Minimizes clamping voltage rise under high di/dt surges, improving protection fidelity. |
| High-temperature reliability | Rated to 150 °C junction - Supports placement near heat sources (e.g., MOSFETs, inductors) without derating penalties. |
| UL497B isolation compliance | Recognized for isolated loop circuits - Enables direct use in 4–20 mA analog loops and PLC I/O modules without additional certification effort. |
| Matte tin lead finish | J-STD-002 compliant - Ensures consistent solder wetting and long-term intermetallic stability in automated assembly. |
Applications
| Industrial Power Supply Input Protection | Automotive Body Control Module (BCM) CAN Bus Line Protection |
|---|---|
|
Use Scenario: 24 V DC input stage of programmable logic controller (PLC) power supply exposed to load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Shunt clamping device placed between VIN and GND, triggered within <1 ns to limit transient overshoot. Use Value: Clamps 14.4 V at 41.7 A ensures downstream DC-DC converter ICs (e.g., LM5017) remain below 16 V absolute maximum rating during 10/1000 µs surges. |
Use Scenario: CAN_H/CAN_L lines in BCM exposed to ESD events during connector mating and in-vehicle cable coupling. IC Role / Device Role / Timing Role: Unidirectional TVS on each line referenced to chassis ground; suppresses ±30 kV ESD per IEC 61000-4-2. Use Value: 1 µA leakage at 85 °C prevents signal distortion on 120 Ω differential bus; 14.4 V clamping protects TJA1042 transceiver's 16 V VIO limit. |
| PoE-Powered Device DC Input Protection | Smart Sensor Node Battery Rail Protection |
|
Use Scenario: 48 V DC input of IEEE 802.3af/at powered device (PD) subjected to Ethernet surge coupling and hot-swap transients. IC Role / Device Role / Timing Role: Primary surge limiter upstream of PD interface controller (e.g., TPS23753), clamping induced spikes before rectification. Use Value: 600 W (10/1000 µs) rating handles full PoE+ surge energy; UL497B recognition validates use in safety-isolated PD architectures. |
Use Scenario: 3.3 V battery rail in wireless environmental sensor node subject to ESD during handling and PCB rework. IC Role / Device Role / Timing Role: Low-leakage TVS placed directly at microcontroller VDD pin to absorb human-body-model (HBM) discharges. Use Value: 0.2 µA leakage at 25 °C preserves multi-year battery life; fast response prevents latch-up in STM32L4-series MCUs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ8.5CA-TR | Bidirectional version; symmetric clamping (±14.4 V); same VRM, VBR, IPP, and package. | Required for AC-coupled or differential signal lines (e.g., RS-485, USB D+/D−) where polarity reversal occurs. | Select only if bidirectional protection is needed; otherwise unidirectional SMBJ8.5A-TR offers lower cost and simpler layout. |
| SMAJ8.5A-TR | Lower PPP rating (400 W vs. 600 W); same VRM/VBR but higher VCL (15.0 V @ 27.8 A); SMA package (smaller footprint, lower thermal mass). | Suitable for space-constrained consumer electronics with lower surge exposure; not recommended for industrial 10/1000 µs compliance. | Choose only for cost-sensitive, low-energy applications; avoid where IEC 61000-4-4 level 4 or UL497B is required. |
Compared with SMBJ8.5CA-TR, the unidirectional SMBJ8.5A-TR provides tighter clamping margin for DC rails and eliminates unnecessary bidirectional capacitance. Against SMAJ8.5A-TR, it delivers 50% higher surge energy handling and certified UL497B compliance-critical for industrial and automotive safety-critical designs.
Availability
SMBJ8.5A-TR is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, PoE-powered devices, and smart sensor nodes requiring stable component supply across extended temperature ranges and regulatory-compliant surge protection.
Supply support for SMBJ8.5A-TR 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 automotive, industrial, and power discrete technologies with vertical manufacturing and broad IP portfolio.
The SMBJ series belongs to ST's Transil™ TVS portfolio, engineered specifically for high-reliability transient suppression in harsh environments-emphasizing low leakage, high-temperature operation, and international safety certifications like UL497B and IEC 61000-4-x.
FAQ
What is the maximum clamping voltage of SMBJ8.5A-TR at 41.7 A?
The maximum clamping voltage (VCL) is 14.4 V under 10/1000 µs waveform conditions at 25 °C ambient, as specified in Table 2 of DS1283 Rev 14. This value increases with junction temperature per the αT coefficient (7.3 × 10−4/°C), reaching ~15.5 V at Tj = 150 °C.
Does SMBJ8.5A-TR meet automotive-grade requirements?
SMBJ8.5A-TR is not AEC-Q200 qualified, but its –55 °C to +150 °C operating junction temperature range, UL497B recognition, and IEC 61000-4-2/4-4 compliance make it suitable for non-safety-critical automotive applications such as body electronics, infotainment power rails, and sensor interfaces-provided system-level qualification is performed.
How does SMBJ8.5A-TR differ from SMBJ8.5CA-TR in circuit implementation?
SMBJ8.5A-TR is unidirectional and must be oriented with cathode toward the protected line and anode to ground; SMBJ8.5CA-TR is bidirectional and symmetrical, allowing placement across any two points without polarity concern. The CA variant exhibits identical electrical specs except for reversed polarity behavior and slightly higher capacitance in AC paths.
Can SMBJ8.5A-TR be used in parallel for higher surge current handling?
No-parallel connection is not recommended due to mismatched dynamic resistance (RD = 0.096 Ω) and VBR tolerances (±5%), which cause current imbalance and premature failure of one device. For >41.7 A surge capability, select a higher-rated part (e.g., SMBJ12A-TR) or implement staged protection with upstream MOVs.
SMBJ8.5A-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJ, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 8.5V
- Voltage - Breakdown (Min):
- 9.4V
- Voltage - Clamping (Max) @ Ipp:
- 14.4V
- Current - Peak Pulse (10/1000µs):
- 41.7A
- 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
SMBJ8.5A-TR FAQ
1.How can I place an order for SMBJ8.5A-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ8.5A-TR 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 SMBJ8.5A-TR reliable?
The price and inventory of SMBJ8.5A-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ8.5A-TR is usually 5 days.
3.What payment methods are accepted for SMBJ8.5A-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ8.5A-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ8.5A-TR?
SMBJ8.5A-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ8.5A-TR 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 SMBJ8.5A-TR?
For technical support, including SMBJ8.5A-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ8.5A-TR requirements.
6.How does Aetrix verify that SMBJ8.5A-TR is sourced from the original manufacturer or authorized distributors?
All SMBJ8.5A-TR 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 SMBJ8.5A-TR meets industry standards.
7.What is the process for return or replacement of SMBJ8.5A-TR?
All SMBJ8.5A-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ8.5A-TR, 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 SMBJ8.5A-TR part is unused and in its original packaging.
Return procedure for SMBJ8.5A-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ8.5A-TR Tags
-
ESD9B5.0ST5G
onsemi
-
DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
-
D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
-
DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
-
D5V0L1B2WS-7
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
