SMA6S18CAH - 18V Bi-Directional 600W TVS Diode | TSC
料号： SMA6S18CAH ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $0.42 | $0.42 |
| 10 | $0.38 | $3.80 |
| 100 | $0.31 | $31.00 |
| 500 | $0.26 | $130.00 |
| 1,000 | $0.22 | $220.00 |
| 3,000 | $0.18 | $540.00 |
SMA6S18CAH 概述
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.
直接替换替代料： SMA6S18CAH ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
快速对比工具——选择替代料号进行并排对比：
SMA6S18AH
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
SMA6S20CAH
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
SMA6S16CAH
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
SMA6J18CA
✅ 直接替换📋 参考替代料（不在目录中）
SMA6J18CA
✅ 直接替换📋 参考替代料（不在目录中）
TPSMA6L18A
✅ 直接替换📋 参考替代料（不在目录中）
SMA6S18CAH 最大额定值与电气特性
| 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 |
| 工作温度范围 | -55C to +150C |
| Storage Temperature Range | -55C to +150C |
| 封装 | SOD-128 |
| 安装类型 | Surface Mount |
| RoHS 状态 | Compliant |
| Lead-Free | Yes |
| Diode Type | TVS - Transient Voltage Suppressor |
SMA6S18CAH 引脚配置
| 引脚 1 | Terminal 1 — Bi-directional terminal (functionally identical to pin 2) |
| 引脚 2 | Terminal 2 — Bi-directional terminal (functionally identical to pin 1) |
典型应用
SMA6S18CAH 适用于 6 应用s: 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.
推荐
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.
推荐
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.
推荐
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.
推荐
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.
推荐
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.
推荐
推荐产品汇总
工程参考数据： SMA6S18CAH ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | 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 |
关键差异点
- Bi-directional polarity in compact SOD-128 footprint （对比 SMA6S18AH (uni-directional, same brand))
- 600 W peak pulse power in low-profile 1.1 mm height package （对比 TPSMA6L18A (400 W Ppp, same footprint))
- Taiwan Semiconductor brand availability across global distributors （对比 SMA6J18CA (Littelfuse / Bourns cross-brand))
设计说明
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.
合规信息
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.
