My Inquiry
My Account
STMicroelectronics SMA6F18AY
;;2.jpg)
- Part No.:
- SMA6F18AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-221AC, SMA Flat Leads
- Datasheet:
-
SMA6F18AY.pdf
- Description:
- TVS DIODE 18VWM 29.2VC SMAFLAT
- Quantity:
- Payment:
- Shipping:
Inventory:2,284
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMA6F18AY from STMicroelectronics is an AEC-Q101-qualified unidirectional automotive TVS diode in SMA 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 contact/air) for robust protection of 12 V/24 V automotive power lines.
For engineers reviewing the SMA6F18AY datasheet, SMA6F18AY pinout, SMA6F18AY application, or SMA6F18AY equivalent, this device is selected for high-reliability surge suppression in battery-supplied ECUs, body control modules, and infotainment power inputs where flat-profile mounting, thermal stability at Tj = 175 °C, and compliance with ISO 7637-2 Pulse 1/2a/3a are mandatory.
Technical Context
This TVS diode uses planar silicon technology to achieve low dynamic resistance (0.326 Ω), stable clamping voltage (29.2 V max at 21.5 A, 10/1000 µs), and minimal temperature coefficient (9.2 × 10⁻⁴ /°C). Its unidirectional configuration enables asymmetric surge handling-blocking reverse surges while conducting forward transients to ground.
It meets stringent automotive stress standards: ISO 7637-2 Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−220 V), and Pulse 3b (+150 V), with verified clamping performance across −55 °C to +175 °C junction range and MSL Level 1 moisture sensitivity rating.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRM) | 18 V - Maximum continuous reverse operating voltage before breakdown; defines minimum system operating margin. |
| Breakdown Voltage (VBR) | 20–22.2 V @ 1 mA - Tight tolerance ensures predictable turn-on during transients without false triggering. |
| Clamping Voltage (VCL) | 29.2 V @ 21.5 A (10/1000 µs) - Limits downstream voltage stress to safe levels for 12 V logic and analog ICs. |
| Peak Pulse Power | 600 W (10/1000 µs), 4 kW (8/20 µs) - Supports both slow automotive load-dump and fast ESD events. |
| Leakage Current | 0.2 µA @ 25 °C, 1 µA @ 85 °C - Enables low-power always-on circuits without battery drain penalty. |
| Junction Temperature Range | −55 to +175 °C - Validated for under-hood placement near engines or power electronics. |
| Dynamic Resistance (RD) | 0.326 Ω - Low impedance ensures rapid voltage stabilization during high-current surges. |
Pinout & Package
SMA6F18AY is housed in a flat, surface-mount SMA Flat package (JEDEC DO-214AC), measuring 2.90 mm × 5.35 mm × 1.10 mm (L × W × H), with matte tin-plated leads and IPC7531-compliant footprint. The package supports reflow soldering per J-STD-020 MSL Level 1 and achieves thermal resistance of ~140 °C/W on 1 cm² copper pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Marked Band) | Surge Return Path | Connected to system ground; conducts transient current when reverse voltage exceeds VRM. |
| Anode | Protected Line Input | Connected to protected line (e.g., battery feed); blocks normal operation but conducts during overvoltage. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive use across temperature, humidity, vibration, and lifetime reliability tests. |
| Flat 1 mm profile | Enables PCB height-constrained layouts in compact ECUs and ADAS modules without mechanical interference. |
| ISO 10605 ±30 kV ESD immunity | Guarantees survival against human-body-model discharges in assembly, service, and field environments. |
| Low αT temperature coefficient | 9.2 × 10⁻⁴ /°C ensures <±5% VBR shift from −40 °C to +125 °C ambient, critical for stable protection. |
| Planar silicon construction | Delivers consistent low leakage and high junction temperature capability versus alloy-junction alternatives. |
Applications
| Body Control Module (BCM) | Infotainment Power Input |
|---|---|
Use Scenario: Protects BCM microcontroller supply rail from load dump and alternator ripple during engine cranking. IC Role / Device Role / Timing Role: Unidirectional TVS clamps negative transients (Pulse 1: −150 V) and positive spikes (Pulse 2a: +112 V) on 12 V input. Use Value: Prevents latch-up or permanent damage to 3.3 V/5 V LDOs and CAN transceivers by limiting voltage to ≤29.2 V. |
Use Scenario: Shields USB-C and HDMI power rails in head units from ESD and hot-swap surges. IC Role / Device Role / Timing Role: Fast-response clamping (8/20 µs) limits ESD-induced overshoot to <39.3 V at 102 A peak. Use Value: Maintains signal integrity and prevents reset events in ARM-based SoCs during ±30 kV air discharge events. |
| ADAS Camera Power Supply | Electric Power Steering (EPS) ECU |
Use Scenario: Secures 5 V camera sensor rail against ignition noise and cable harness coupling in rear-view systems. IC Role / Device Role / Timing Role: Low-leakage (0.2 µA) operation avoids bias current errors in precision analog front-ends. Use Value: Ensures uninterrupted image capture during repeated ISO 7637-2 Pulse 3a (−220 V) events without thermal runaway. |
Use Scenario: Guards motor driver gate-drive supply against inductive kickback from 3-phase BLDC motors. IC Role / Device Role / Timing Role: High-power clamping (400 W @ Tj = 175 °C) sustains protection during sustained overvoltage conditions. Use Value: Eliminates need for secondary crowbar circuits, reducing BOM count and board area in safety-critical EPS designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A | Lower peak power (400 W), higher VCL (32.4 V @ 19.4 A), same SMA package | Limited to non-load-dump applications; insufficient for ISO 7637-2 Pulse 1 compliance | Select only if system transients are ESD-only and thermal derating below 150 °C is acceptable. |
| SMBJ18A | Higher package thermal resistance (SMB vs SMA), 600 W rating but lower Ipp (21.5 A → 19.4 A), same VBR range | Less effective heat dissipation in high-density layouts; requires larger copper area for equivalent Tj control | Prefer only when existing SMB footprint reuse is required and board-level thermal management is enhanced. |
Compared with SMAJ18A and SMBJ18A, SMA6F18AY provides superior thermal robustness (175 °C Tj max), tighter VCL (29.2 V), and full ISO 7637-2 Pulse 1/2a/3a coverage-making it the only choice for next-generation ASIL-B power rail protection where long-term reliability under thermal cycling is non-negotiable.
Availability
SMA6F18AY is available at Aetrix Electronics and suitable for automotive electronic control units, body electronics modules, and advanced driver-assistance systems requiring stable component supply with AEC-Q101 traceability and full ISO 7637/10605 compliance.
Supply support for SMA6F18AY 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 automotive-grade analog, power, and microcontroller solutions with vertical manufacturing and rigorous quality certification.
SMA6FxxAY belongs to ST's Transil™ automotive TVS family, engineered specifically for ISO 7637-2 and ISO 10605 compliance in 12 V/24 V vehicle networks-prioritizing thermal resilience, low leakage, and flat-profile integration in space-constrained ECUs.
FAQ
What is the maximum clamping voltage of SMA6F18AY under a 10/1000 µs surge?
The maximum clamping voltage is 29.2 V at 21.5 A peak pulse current for a 10/1000 µs waveform, measured at Tj = 25 °C. This value increases linearly with junction temperature using the 9.2 × 10⁻⁴ /°C coefficient, reaching ~31.5 V at Tj = 175 °C.
Can SMA6F18AY be used in 24 V automotive systems?
Yes-its 18 V stand-off voltage and 29.2 V clamping level provide adequate margin above nominal 24 V system peaks (typically ≤28 V), and its 175 °C junction rating supports under-hood deployment. However, verify system transient amplitude does not exceed 40 V to maintain safe operating area.
Does SMA6F18AY meet ISO 7637-2 Pulse 1 requirements?
Yes-it is explicitly validated for ISO 7637-2 Pulse 1 (−150 V, 50 Ω source impedance) with clamping performance confirmed in Figure 12 of DS12477. The device limits voltage to ≤29.2 V during the pulse, protecting downstream 3.3 V/5 V logic interfaces.
What is the recommended PCB footprint for optimal thermal performance?
Use the JEDEC-registered SMA Flat footprint per Figure 17 in DS12477: 2.5 mm × 5.5 mm pad layout with ≥1 cm² copper pour per terminal. Thermal resistance drops from ~140 °C/W to ~85 °C/W with 2 cm² total copper, enabling sustained 400 W operation at Tj = 175 °C.
SMA6F18AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-221AC, SMA Flat Leads
- Series:
- SMA6F
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 18V
- 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:
- SMAflat
SMA6F18AY FAQ
1.How can I place an order for SMA6F18AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA6F18AY 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 SMA6F18AY reliable?
The price and inventory of SMA6F18AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA6F18AY is usually 5 days.
3.What payment methods are accepted for SMA6F18AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA6F18AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA6F18AY?
SMA6F18AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA6F18AY 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 SMA6F18AY?
For technical support, including SMA6F18AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA6F18AY requirements.
6.How does Aetrix verify that SMA6F18AY is sourced from the original manufacturer or authorized distributors?
All SMA6F18AY 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 SMA6F18AY meets industry standards.
7.What is the process for return or replacement of SMA6F18AY?
All SMA6F18AY units undergo pre-shipment inspection (PSI). If there is an issue with SMA6F18AY, 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 SMA6F18AY part is unused and in its original packaging.
Return procedure for SMA6F18AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMA6F18AY 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…
