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Taiwan Semiconductor Corporation SMAJ188C
- Part No.:
- SMAJ188C
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ188C.pdf
- Description:
- 300W, 232V, 10%, BIDIRECTIONAL,
- Quantity:
- Payment:
- Shipping:
Inventory:6,374
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Product details
Overview
SMAJ188C from Taiwan Semiconductor is a unidirectional 400W transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for high-energy surge protection in DC power rails. It features a 188V working stand-off voltage (VWM), 209–255V breakdown voltage (VBR), and clamps to ≤344V at 0.9A peak impulse current under 10/1000μs waveform - suitable for automotive ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance and industrial DC/DC converter input protection.
For engineers reviewing the SMAJ188C datasheet, SMAJ188C pinout, SMAJ188C application, or SMAJ188C equivalent, this page delivers verified electrical parameters, DO-214AC terminal mapping, bidirectional capability context (C suffix denotes unidirectional), clamping performance under standardized surge waveforms, and real-world selection guidance against comparable TVS diodes for overvoltage hardening of 12–48V systems.
Technical Context
The SMAJ188C operates as a unidirectional avalanche diode with glass-passivated junction, enabling fast response (<1.0ps rise time from 0V to VBR min) and low leakage (<1μA at VWM). Its 150°C maximum junction temperature and -55°C to +150°C operating range support under-hood and industrial ambient conditions.
It delivers 400W peak pulse power (10/1000μs) up to 78V VWM; above 78V, rating reduces to 300W - confirmed by absolute maximum ratings table and derating curve (Fig.2). The device meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements per its DO-214AC molding compound.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 188 V - Maximum continuous reverse voltage before clamping begins; defines safe operating margin for 180–190V DC bus applications. |
| VBR min/max | 209 V / 255 V @ 1 mA - Confirmed breakdown threshold range; ensures reliable triggering above VWM with design margin. |
| VC @ IPPM | ≤344 V @ 0.9 A - Clamped voltage during 10/1000μs surge; determines protected circuit's maximum transient exposure. |
| PPPM | 400 W (10/1000μs) - Peak surge energy handling capacity; supports single-event transients per ISO 7637-2. |
| IR @ VWM | ≤1 μA - Reverse leakage at rated stand-off; minimizes standby power loss in high-impedance sensing or battery-backed rails. |
| Package | DO-214AC (SMA) - Surface-mount outline with cathode band marking; compatible with automated placement and reflow profiles. |
| Polarity | Unidirectional - Cathode-banded terminal conducts forward during positive surges only; requires correct orientation on PCB. |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with matte tin-plated leads, cathode band indicating terminal 1 (cathode), terminal 2 (anode); weight ≈0.060g; moisture sensitivity level 1 (J-STD-020).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Terminal 1 (Banded end) | Cathode | Connected to protected line (e.g., +Vin); conducts avalanche current when line voltage exceeds VBR relative to ground. |
| Terminal 2 | Anode | Typically tied to system ground or low-side reference; completes surge current path during clamping event. |
Key Features
| Feature | Design Value |
|---|---|
| Fast response time | <1.0 ps from 0 V to VBR min - enables suppression before sensitive downstream ICs experience overvoltage stress. |
| Glass passivated junction | Enhanced reliability and stable VBR over temperature and lifetime vs. non-passivated alternatives. |
| ISO 7637-2 compliance | Validated for Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling) - critical for automotive ECUs. |
| RoHS & halogen-free | Meets IEC 61249-2-21 and EU RoHS directives - supports green manufacturing and end-of-life compliance. |
| Automated placement ready | DO-214AC footprint and lead finish comply with J-STD-002 solderability standards - ensures high-yield SMT assembly. |
Applications
| Automotive ECU Power Input | Industrial DC/DC Converter Input |
|---|---|
Use Scenario: Protecting microcontroller power supply inputs in engine control units exposed to load dump and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS clamping transient energy on 12V/24V rail before it reaches LDOs or PMICs. Use Value: Limits peak voltage to ≤344V during ISO 7637-2 Pulse 1 (12V systems), preventing latch-up or gate oxide damage in downstream silicon. |
Use Scenario: Safeguarding isolated DC/DC converter primary-side input against switching noise and external surges in factory automation PLCs. IC Role / Device Role / Timing Role: Standoff-rated surge absorber placed upstream of input filter capacitors and active rectifiers. Use Value: Absorbs 400W pulses without degradation, maintaining <1μA leakage to avoid loading 48V backplane monitoring circuits. |
| LED Driver Power Stage | Telecom Power Interface |
Use Scenario: Overvoltage protection for constant-current LED drivers in streetlight systems subject to lightning-induced surges. IC Role / Device Role / Timing Role: Primary-line TVS on HV DC bus (e.g., 150–200V) to clamp induced transients before buck controller ICs. Use Value: 188V VWM aligns with 200V nominal bus; 344V clamping ensures MOSFETs and gate drivers remain within SOA limits. |
Use Scenario: Front-end surge suppression on 48V telecom power feeds entering base station equipment cabinets. IC Role / Device Role / Timing Role: First-stage protector on -48V DC input, coordinated with downstream GDTs and MOVs in multi-stage architecture. Use Value: Low IR (<1μA) prevents drift in precision current-sense resistors used for remote power monitoring and billing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ188A | Breakdown range 209–231V (narrower than SMAJ188C's 209–255V); same VWM (188V), lower VC (328V vs. 344V). | Better clamping ratio for margin-critical 180V rails; identical DO-214AC footprint and polarity. | Select SMAJ188A if tighter VBR tolerance and lower clamping voltage are required; verify layout compatibility with cathode band orientation. |
| ON Semiconductor 1.5SMC188A | Same VWM (188V), but higher PPPM (1500W), larger DO-214AB (SMB) package, and higher IR (5μA). | Higher surge capacity suits repeated transient environments (e.g., motor drives); SMB footprint requires PCB redesign. | Choose 1.5SMC188A only when 1500W rating is mandatory and board space allows DO-214AB; not drop-in for SMAJ188C. |
Compared with SMAJ188C, SMAJ188A offers improved clamping consistency at the cost of reduced upper VBR margin, while 1.5SMC188A trades package compatibility for significantly higher surge endurance - making SMAJ188C optimal for space-constrained, single-event ISO 7637-2 compliant designs where leakage and footprint are prioritized.
Availability
SMAJ188C is available at Aetrix Electronics and suitable for automotive ECU protection, industrial DC/DC converter input hardening, and LED driver power stage surge suppression requiring stable component supply across production lifecycles.
Supply support for SMAJ188C 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
Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in TVS diodes, rectifiers, and power devices since 1979.
The SMAJ series was developed specifically for surface-mount surge protection in automotive and industrial power systems, emphasizing robustness under ISO 7637-2 pulses, tight parametric control, and high-reliability packaging for extended thermal cycling.
FAQ
What is the polarity configuration of SMAJ188C?
The SMAJ188C is a unidirectional TVS diode, marked with a cathode band on Terminal 1. It conducts avalanche current only when the anode (Terminal 2) is at a lower potential than the cathode (Terminal 1) - meaning it protects against positive transients on the cathode-connected line. This configuration is essential for proper integration into DC power rails where polarity is fixed, such as automotive 12V/24V systems. Always orient the SMAJ188C with the banded end toward the protected voltage source.
Does SMAJ188C meet automotive surge immunity standards?
Yes, SMAJ188C meets ISO 7637-2 requirements for Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling), as explicitly stated in the manufacturer's datasheet. Its 400W peak pulse power rating (10/1000μs), fast response time (<1.0ps), and clamping voltage of ≤344V at 0.9A ensure compliance in 12V and 24V vehicle networks. Engineers deploying SMAJ188C in ECUs or body control modules can rely on its validated performance without additional external filtering.
How does the clamping voltage of SMAJ188C compare to its breakdown voltage?
The SMAJ188C has a breakdown voltage (VBR) range of 209–255V at 1mA test current, while its maximum clamping voltage (VC) is 344V at 0.9A peak impulse current (10/1000μs). This ~35–65% clamping ratio reflects the device's ability to limit transient overvoltage well above VBR but within safe limits for downstream components. For example, at 188V working voltage, the 344V clamping ceiling provides 156V headroom - sufficient to protect 300V-rated MOSFETs or 350V-input DC/DC controllers without overstressing their absolute maximum ratings.
Can SMAJ188C be used in bidirectional surge protection circuits?
No - SMAJ188C is strictly unidirectional, as indicated by the "C" suffix per Taiwan Semiconductor's ordering convention (C = unidirectional, CA = bidirectional). For bidirectional protection, the SMAJ188CA variant must be used instead. Attempting to use SMAJ188C in AC or reversible-polarity applications will result in forward conduction during negative transients, potentially causing failure or short-circuit behavior. Always confirm suffix designation and verify polarity marking before schematic placement of SMAJ188C.
What is the maximum junction temperature and thermal derating behavior of SMAJ188C?
The SMAJ188C has a maximum junction temperature (TJ MAX) of 150°C and operates from -55°C to +150°C. Its peak pulse power rating of 400W (10/1000μs) is specified at TA = 25°C and derates linearly above that ambient, per Fig.2 in the datasheet - e.g., at 85°C ambient, usable PPPM drops to approximately 260W. This derating must be applied in thermally constrained enclosures (e.g., sealed automotive junction boxes) to prevent thermal runaway during repetitive surge events. The DO-214AC package's low thermal resistance supports effective PCB copper pour heatsinking.
SMAJ188C Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AC, SMA
- Series:
- SMAJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 188V
- Voltage - Breakdown (Min):
- 209V
- Voltage - Clamping (Max) @ Ipp:
- 344V
- Current - Peak Pulse (10/1000µs):
- 900mA
- Power - Peak Pulse:
- 400W
- 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:
- DO-214AC (SMA)
SMAJ188C FAQ
1.How can I place an order for SMAJ188C through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ188C 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 SMAJ188C reliable?
The price and inventory of SMAJ188C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ188C is usually 5 days.
3.What payment methods are accepted for SMAJ188C?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ188C transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ188C?
SMAJ188C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ188C 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 SMAJ188C?
For technical support, including SMAJ188C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ188C requirements.
6.How does Aetrix verify that SMAJ188C is sourced from the original manufacturer or authorized distributors?
All SMAJ188C 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 SMAJ188C meets industry standards.
7.What is the process for return or replacement of SMAJ188C?
All SMAJ188C units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ188C, 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 SMAJ188C part is unused and in its original packaging.
Return procedure for SMAJ188C:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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