My Inquiry
My Account
STMicroelectronics SMB6F18AY
- Part No.:
- SMB6F18AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-221AA, SMB Flat Leads
- Datasheet:
-
SMB6F18AY.pdf
- Description:
- TVS DIODE 18VWM 29.2VC SMBFLAT
- Quantity:
- Payment:
- Shipping:
Inventory:8,436
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMB6F18AY from STMicroelectronics is an AEC-Q101 qualified unidirectional automotive TVS diode in SMB Flat package, designed to clamp transient overvoltages up to 29.2 V (10/1000 µs) at 21.5 A peak pulse current while maintaining low leakage (0.2 µA @ 25 °C) and operating up to 175 °C junction temperature. It delivers 600 W peak pulse power (10/1000 µs) and exceeds ISO 10605 ESD immunity (±30 kV air/contact) and ISO 7637-2 Pulse 1/2a/3a/3b surge levels for 12 V battery systems.
For engineers reviewing the SMB6F18AY datasheet, SMB6F18AY pinout, SMB6F18AY application, or SMB6F18AY equivalent, key selection criteria include clamping voltage (29.2 V), stand-off voltage (18 V), dynamic resistance (0.326 Ω), high-temperature reliability (Tj max = 175 °C), and compliance with automotive surge/ESD standards including ISO 7637-2 and ISO 10605.
Technical Context
This unidirectional TVS diode uses planar silicon technology to achieve low leakage current (0.2 µA @ 25 °C, 1 µA @ 85 °C) and stable clamping performance across its full operating junction temperature range (–55 to +175 °C). Its flat 1 mm profile and matte tin-plated leads support automated assembly per J-STD-002 and IPC7531 footprint requirements.
The device is optimized for automotive power line protection where precise voltage standoff (VRM = 18 V), tight VBR tolerance (20–22.2 V), and low dynamic resistance (0.326 Ω) ensure rapid response to ISO 7637-2 transients such as Pulse 1 (–150 V), Pulse 2a (+112 V), Pulse 3a (–220 V), and Pulse 3b (+150 V) on 12 V battery networks.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRM) | 18 V - Maximum continuous reverse working voltage before breakdown; defines system operating margin against normal battery fluctuations. |
| Breakdown Voltage (VBR) | 20–22.2 V @ 1 mA - Guaranteed conduction onset range; ensures reliable triggering during surges without premature activation. |
| Clamping Voltage (VCL) | 29.2 V @ 21.5 A (10/1000 µs) - Peak voltage seen by protected circuit during worst-case surge; directly limits stress on downstream ICs. |
| Peak Pulse Power (PPP) | 600 W @ 10/1000 µs - Sustained energy-handling capability under standardized surge waveform; validates robustness for automotive load dump events. |
| Dynamic Resistance (RD) | 0.326 Ω - Low incremental resistance during clamping; minimizes voltage overshoot and improves current-sharing predictability. |
| Junction Temperature Range | –55 to +175 °C - Enables operation in engine bay and powertrain environments without derating or thermal shutdown. |
| Leakage Current (IRM) | 0.2 µA @ 25 °C - Negligible standby power loss; critical for always-on automotive modules with strict quiescent current budgets. |
Pinout & Package
SMB6F18AY is housed in an SMB Flat package (JEDEC registered outline), measuring 3.3–3.95 mm × 5.2–5.6 mm × 0.9–1.1 mm height, with 1 mm profile optimized for space-constrained automotive PCBs. The package features matte tin-plated leads compliant with JESD 22-B102 E3 and MIL-STD-750 method 2026.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Marked Band) | Surge Current Sink | Connected to protected line; conducts transient energy to ground when voltage exceeds VRM; polarity-critical for unidirectional operation. |
| Anode | Reference / Ground Return | Typically tied to chassis or battery ground; completes clamping path; must maintain low-impedance connection to handle 21.5 A peak pulses. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive under-hood use with extended temperature cycling, mechanical shock, and humidity testing per JEDEC standards. |
| ISO 7637-2 compliance | Withstands defined transients: Pulse 1 (–150 V), Pulse 2a (+112 V), Pulse 3a (–220 V), Pulse 3b (+150 V) without degradation. |
| ISO 10605 ESD immunity | Survives ±30 kV contact and air discharge (C = 150 pF/R = 330 Ω and C = 330 pF/R = 330 Ω), exceeding Level 4 requirements. |
| Low-profile SMB Flat | 1 mm height enables placement beneath connectors or near ECU housings; compatible with IPC7531 footprint and automated reflow (J-STD-020 MSL 1). |
| High-temperature stability | Specified performance maintained up to Tj = 175 °C; clamping voltage drift compensated via αT = 9.2 × 10⁻⁴/°C coefficient. |
Applications
| Body Control Module (BCM) | Infotainment Power Supply |
|---|---|
Use Scenario: Protects 12 V input rails of BCMs from load dump, jump-start spikes, and alternator ripple. IC Role / Device Role / Timing Role: Primary transient voltage suppressor on main power entry point; clamps surges before they reach LDOs and microcontrollers. Use Value: Prevents latch-up or permanent damage to CAN transceivers and power management ICs during ISO 7637-2 Pulse 1 and Pulse 3b events. |
Use Scenario: Shields USB-C PD and display power rails in head units from ESD and ignition-induced transients. IC Role / Device Role / Timing Role: Secondary-level TVS placed after DC-DC converters to suppress fast-rising ESD (IEC 61000-4-2) and conducted noise. Use Value: Maintains <0.2 µA leakage to avoid battery drain in parked mode while clamping ±30 kV ESD to <29.2 V at 21.5 A. |
| ADAS Camera Module | Electric Power Steering (EPS) |
Use Scenario: Safeguards MIPI CSI-2 interface power and I²C control lines against hot-swap and cable discharge events. IC Role / Device Role / Timing Role: Localized TVS on camera board power inputs; coordinates with ferrite beads to form low-pass filter for EMC robustness. Use Value: Ensures uninterrupted video streaming by limiting clamping overshoot to 29.2 V during 8/20 µs ESD bursts, preserving signal integrity. |
Use Scenario: Guards motor driver supply rails against inductive kickback from steering column actuator coils. IC Role / Device Role / Timing Role: High-energy TVS on H-bridge VDD rail; absorbs Pulse 2a (+112 V) and Pulse 3a (–220 V) without thermal runaway. Use Value: Delivers 470 W clamping power at Tj = 175 °C, enabling sustained operation during repeated EPS assist cycles in high-ambient conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional automotive TVS applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ18A | Same SMB package but rated for 600 W (10/1000 µs); VBR = 20–22.1 V, VCL = 29.2 V @ 20.9 A; no AEC-Q101 qualification. | Lacks automotive qualification; suitable for industrial/commercial 12 V systems but not OEM vehicle production. | Select SMBJ18A only for non-automotive designs where AEC-Q101 is not mandated and cost sensitivity outweighs qualification needs. |
| TPSMA6L18A | SMB package, AEC-Q101 qualified; VBR = 20–22.1 V, VCL = 29.2 V @ 21.5 A; same PPP rating but higher RD (0.35 Ω vs. 0.326 Ω). | Identical surge/ESD ratings; slightly higher dynamic resistance may increase clamping overshoot marginally under extreme pulse repetition. | Choose TPSMA6L18A if dual-sourcing is required and TI's supply chain offers better lead time or volume pricing for Tier 1 programs. |
Compared with SMBJ18A and TPSMA6L18A, SMB6F18AY provides the lowest dynamic resistance (0.326 Ω) and highest junction temperature rating (175 °C), making it optimal for thermally constrained automotive modules requiring long-term reliability under repeated surge stress.
Availability
SMB6F18AY is available at Aetrix Electronics and suitable for body control modules, ADAS camera power supplies, infotainment systems, and electric power steering ECUs requiring stable component supply across automotive production lifecycles.
Supply support for SMB6F18AY 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, delivering intelligent power, sensing, and control solutions for automotive, industrial, and consumer markets.
SMB6F18AY belongs to the SMB6FxxAY series - a family of AEC-Q101 qualified unidirectional TVS diodes engineered specifically for ISO 7637-2 and ISO 10605 compliance in 12 V automotive electrical architectures.
FAQ
What is the maximum clamping voltage of SMB6F18AY under a 10/1000 µs surge?
The maximum clamping voltage (VCL) of SMB6F18AY is 29.2 V when subjected to a 10/1000 µs surge at 21.5 A peak current, as specified in Table 2 of DS12412 Rev 1. This value is measured at Tamb = 25 °C and remains stable up to Tj = 175 °C due to its temperature-compensated design (αT = 9.2 × 10⁻⁴/°C).
Does SMB6F18AY meet ISO 7637-2 Pulse 3a and Pulse 3b requirements?
Yes, SMB6F18AY is explicitly validated for ISO 7637-2 Pulse 3a (–220 V) and Pulse 3b (+150 V) on 12 V battery systems, as confirmed in the "Description" section and Figure 12–15 of DS12412. Its 600 W peak pulse power rating and low dynamic resistance ensure reliable suppression without failure under these waveforms.
Can SMB6F18AY be used in bidirectional configurations?
No, SMB6F18AY is a unidirectional TVS diode, indicated by the "A" suffix in its ordering code and confirmed in the "Description" and "Characteristics" sections. It conducts only in reverse bias above VRM = 18 V. For bidirectional protection, ST offers the SMB6FxxCA series, which is not pin-compatible or functionally interchangeable.
What is the recommended PCB footprint for SMB6F18AY?
The recommended footprint follows IPC7531 and is detailed in Figure 17 of DS12412: pad length 3.44 mm (0.136 in), pad width 1.20 mm (0.047 in), center-to-center spacing 5.84 mm (0.230 in), and solder mask opening matching copper. Thermal relief via copper area under each lead improves Rth(j-a) to ≤150 °C/W per Figure 11.
SMB6F18AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-221AA, SMB Flat Leads
- Series:
- SMB6FxxAY
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 18V (Max)
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 29.2V
- Current - Peak Pulse (10/1000µs):
- 21.5A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMBflat
SMB6F18AY FAQ
1.How can I place an order for SMB6F18AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SMB6F18AY 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 SMB6F18AY reliable?
The price and inventory of SMB6F18AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMB6F18AY is usually 5 days.
3.What payment methods are accepted for SMB6F18AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMB6F18AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMB6F18AY?
SMB6F18AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMB6F18AY 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 SMB6F18AY?
For technical support, including SMB6F18AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMB6F18AY requirements.
6.How does Aetrix verify that SMB6F18AY is sourced from the original manufacturer or authorized distributors?
All SMB6F18AY 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 SMB6F18AY meets industry standards.
7.What is the process for return or replacement of SMB6F18AY?
All SMB6F18AY units undergo pre-shipment inspection (PSI). If there is an issue with SMB6F18AY, 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 SMB6F18AY part is unused and in its original packaging.
Return procedure for SMB6F18AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMB6F18AY 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…
