SMA6S18CAH - 18V Bi-Directional 600W TVS Diode | TSC
MPN: SMA6S18CAH ✓ Hoạt độngSMA6S18CAH Tóm tắt
A Transient Voltage Suppressor is a specialized PN-junction diode optimized for avalanche breakdown operation. Under normal circuit conditions the TVS diode presents a high impedance and is effectively invisible to the signal or supply rail it protects. When the voltage across the device exceeds its breakdown (avalanche) voltage, the TVS diode conducts heavily and shunts the transient energy away from sensitive downstream components. Bi-directional TVS diodes such as the SMA6S18CAH clamp both positive and negative transients symmetrically, making them ideal for AC-coupled signal lines, differential data pairs, and DC supply rails where the polarity of the disturbance is undefined.
Key electrical characteristics include a stand-off voltage (Vrwm) of 18 V, breakdown voltage (Vbr) typically 20 V, and a clamping voltage (Vc) of 29.2 V at 20.5 A peak pulse current. The 600 W peak pulse power rating is specified at a 10/1000 microsecond waveform per industry-standard TVS test methods. The device is housed in a SOD-128 (also known as SMA-flat) low-profile surface-mount package that is pin-compatible with the industry-standard SMA footprint, enabling direct substitution on existing PCB land patterns.
Typical applications include protection of 12 V or 15 V DC power rails in industrial control systems, automotive electronic control units (ECUs), USB and HDMI data-line protection, and protection of signal lines on factory automation buses such as RS-485 and CAN. The fast response time (sub-nanosecond avalanche) makes the SMA6S18CAH well-suited for safeguarding microcontroller I/O pins and sensor interfaces from electrostatic discharge events.
When designing with this device, ensure the working standoff voltage (Vrwm) exceeds the maximum continuous operating voltage of the protected line, and select a clamping voltage (Vc) safely below the absolute maximum rating of the downstream component. PCB layout should minimize parasitic inductance between the TVS diode and the protected line, with short, wide traces to the ground plane to ensure effective transient energy dissipation.
Bộ thay thế dễ dàng lắp đặt cho SMA6S18CAH — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
SMA6S18AH
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
SMA6S20CAH
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
SMA6S16CAH
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
SMA6J18CA
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
SMA6J18CA
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
TPSMA6L18A
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
SMA6S18CAH Tỷ lệ tối đa & tính chất điện
| Working Peak Reverse Voltage (Vrwm) | 18 V |
| Breakdown Voltage (Vbr) typical | 20 V |
| Clamping Voltage (Vc) at Ipp | 29.2 V |
| Peak Pulse Current (Ipp) 10/1000us | 20.5 A |
| Peak Pulse Power (Ppp) 10/1000us | 600 W |
| Polarity | Bi-directional |
| Maximum Clamping Voltage (Vc max) | 29.2 V |
| Khoảng nhiệt độ hoạt động | -55C to +150C |
| Storage Temperature Range | -55C to +150C |
| Hộp | SOD-128 |
| Kiểu lắp đặt | Surface Mount |
| Trạng thái RoHS | Compliant |
| Lead-Free | Yes |
| Diode Type | TVS - Transient Voltage Suppressor |
Cấu hình chân SMA6S18CAH
| Chân 1 | Terminal 1 — Bi-directional terminal (functionally identical to pin 2) |
| Chân 2 | Terminal 2 — Bi-directional terminal (functionally identical to pin 1) |
Ứng dụng tiêu biểu
SMA6S18CAH phù hợp cho 6 Áp dụngs: 12V Industrial DC Rail Protection, Automotive ECU Transient Protection, USB and HDMI Data Line Protection, RS-485 and CAN Bus Protection, Sensor Interface Protection, LED Lighting Driver Protection.
12V Industrial DC Rail Protection
The SMA6S18CAH is well matched for 12 V industrial DC rail protection because its 18 V Vrwm provides 6 V of headroom above the nominal 12 V supply while the 29.2 V clamping voltage stays safely below the 36 V absolute maximum rating of typical 12 V system ICs. Placed in parallel with the rail close to the connector, the TVS diode shunts load-dump transients from motors and solenoids. Its 600 W peak pulse power handles the most demanding industrial surge events including 8/20 us lightning-induced transients without degradation.
Được đề xuất
Automotive ECU Transient Protection
For automotive ECU protection the SMA6S18CAH offers an 18 V working voltage that accommodates load-dump transients up to 35 V on 12 V automotive buses. The 29.2 V clamping voltage remains below the 40 V transient rating required by ISO 7637-2 for most automotive ICs. Surface-mount SOD-128 packaging supports the small form factors demanded by modern ECU designs. The bi-directional polarity protects against both positive load-dump and negative jump-start transients that occur in automotive electrical systems.
Được đề xuất
USB and HDMI Data Line Protection
The SMA6S18CAH clamps ESD and cable-discharge events on USB and HDMI data lines when the interface voltage is in the 5 V to 15 V range. Sub-nanosecond avalanche response of the TVS diode ensures clamping occurs before the transient reaches the PHY or controller IC, preventing latch-up and dielectric breakdown. The SOD-128 package fits behind the connector footprint with minimal stub length, preserving signal integrity at USB 2.0 and HDMI 1.4 data rates. Bi-directional operation handles both positive and negative ESD discharges per IEC 61000-4-2.
Được đề xuất
RS-485 and CAN Bus Protection
In RS-485 and CAN bus protection the SMA6S18CAH is placed at each end of the bus to clamp common-mode transients from cable discharge and nearby lightning events. With an 18 V Vrwm it tolerates the 12 V common-mode bias typical of these buses while the 29.2 V clamping voltage prevents damage to transceiver absolute-maximum ratings of typically 36 V. The 600 W rating handles the worst-case surge events from outdoor cable runs in industrial and building-automation environments.
Được đề xuất
Sensor Interface Protection
The SMA6S18CAH protects analog sensor interfaces operating on 12 V or 15 V rails from ESD and switching transients. The 18 V Vrwm exceeds the normal signal range and the 29.2 V clamping voltage stays below the 36 V abs-max of typical sensor signal-conditioning ICs. Fast avalanche response ensures transient events are clamped before they can propagate into the ADC front-end, preserving measurement accuracy. The SOD-128 footprint fits alongside common SOIC-8 sensor packages on compact PCB designs.
Được đề xuất
LED Lighting Driver Protection
In LED lighting driver designs the SMA6S18CAH provides surge protection for 12 V and 24 V LED driver circuits exposed to inductive switching transients from dimmers and power-factor-correction stages. The 18 V Vrwm matches common LED driver rails while the 29.2 V clamping voltage prevents overvoltage damage to downstream LED strings and current-sense resistors. The low-profile SOD-128 package fits within the height constraints of linear LED fixtures and downlights.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho SMA6S18CAH — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | SMA6J18CA | SMA6S20CAH | SMA6S16CAH | TPSMA6L18A |
|---|---|---|---|---|---|
| Package | SOD-128 | SOD-128 - same | SOD-128 - same | SOD-128 - same | SOD-128 - same |
| Brand | Taiwan Semiconductor Corporation | Littelfuse / Bourns | Taiwan Semiconductor Corporation | Taiwan Semiconductor Corporation | Littelfuse |
| Working Voltage (Vrwm) | 18 V | 18 V | 20 V | 16 V | 18 V |
| Clamping Voltage (Vc) | 29.2 V | 29.2 V | 32.4 V | 26 V | 29.2 V |
| Peak Pulse Power (Ppp) | 600 W | 600 W | 600 W | 600 W | 400 W |
| Peak Pulse Current (Ipp) | 20.5 A | 20.5 A | 18.6 A | 23.1 A | 13.7 A |
| Polarity | Bi-directional | Bi-directional | Bi-directional | Bi-directional | Uni-directional |
| Operating Temperature | -55C to +150C | -55C to +150C | -55C to +150C | -55C to +150C | -55C to +150C |
Bảo phân biệt quan trọng
- Bi-directional polarity in compact SOD-128 footprint (vsSMA6S18AH (uni-directional, same brand))
- 600 W peak pulse power in low-profile 1.1 mm height package (vsTPSMA6L18A (400 W Ppp, same footprint))
- Taiwan Semiconductor brand availability across global distributors (vsSMA6J18CA (Littelfuse / Bourns cross-brand))
Ghi chú thiết kế
When substituting the bi-directional SMA6S18CAH with a uni-directional TVS in the same package, verify that the application can tolerate the higher leakage current and asymmetric clamping behavior. Uni-directional parts typically have lower capacitance and leakage but only clamp one polarity. For DC rails where polarity is defined, uni-directional is preferred; for signal lines or unknown-polarity transients, bi-directional is mandatory. Always check the maximum reverse leakage current (Ir) at Vrwm to ensure it does not load the protected line.
Place the SMA6S18CAH as close as physically possible to the connector or entry point of the transient source. Use short, wide PCB traces (at least 20 mil width for the TVS pads) and a solid ground plane connection to minimize parasitic inductance. Estimated: even 5 nH of trace inductance at 20 A/us transient edge rates can generate 100 V of additional overshoot, exceeding the 29.2 V clamping voltage. A via-in-pad or stitching vias to the ground plane are recommended for high-energy transient applications.
The 600 W peak pulse power rating applies to a single 10/1000 us pulse at 25C initial temperature. For repetitive surge events or elevated ambient temperatures, derate according to the steady-state power dissipation of the SOD-128 package, which is approximately 1 W at 25C. Estimated: at 85C ambient, the maximum continuous power dissipation drops to roughly 0.6 W. If the application experiences frequent transients (more than once per minute), consider a heatsunk or higher-power TVS in a DO-214AB (SMC) package.
Thông tin tuân thủ
RoHS and REACH compliant per TSC product page. Not AEC-Q100 qualified; for automotive applications requiring this certification, verify with TSC or select an AEC-Q100-qualified alternative from onsemi or Nexperia in the same SOD-128 package.
