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Taiwan Semiconductor Corporation SMAJ188AH
- Part No.:
- SMAJ188AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ188AH.pdf
- Description:
- TVS DIODE 188VWM 328VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,736
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Product details
Overview
SMAJ188AH from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for high-energy surge protection in DC power rails. It features a 188 V working stand-off voltage (VWM), 209–231 V breakdown voltage (VBR), 328 V maximum clamping voltage (VC) at 0.9 A peak impulse current, and 400 W peak pulse power rating with 10/1000 µs waveform - suitable for automotive-grade ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance in on-board DC/DC converters.
For engineers reviewing the SMAJ188AH datasheet, SMAJ188AH pinout, SMAJ188AH application, or SMAJ188AH equivalent, key selection criteria include its DO-214AC (SMA) package compatibility, AEC-Q101 qualification, <1.0 ps response time, sub-1 µA leakage at 188 V, and bidirectional-capable variant options (e.g., SMAJ188CH) where polarity reversal protection is required.
Technical Context
The SMAJ188AH operates as a unidirectional avalanche diode, leveraging glass-passivated junction technology to achieve fast transient suppression with minimal capacitance. Its clamping behavior is defined by a 10/1000 µs standard surge waveform, and thermal performance is rated for continuous operation from –55 °C to +150 °C junction temperature.
It meets ISO 7637-2 immunity requirements for automotive electronics, including Pulse 1 (inductive load dump simulation), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling noise). The device is not bidirectional by default - bidirectional variants use CH or CAH suffixes and share identical VWM/VBR/VC specs but support reverse-polarity surge conduction.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 188 V - maximum continuous DC operating voltage before leakage exceeds 1 µA; defines safe rail margin for 188 V nominal systems |
| VBR min/max | 209–231 V @ 1 mA - verified avalanche onset range ensuring predictable turn-on during overvoltage events |
| VC @ IPPM | 328 V @ 0.9 A - clamped voltage during 10/1000 µs surge; limits downstream IC stress to ≤328 V |
| PPPM | 400 W - peak pulse power handling per 10/1000 µs waveform; derates linearly above 25 °C ambient |
| TJ max | +150 °C - maximum junction temperature enabling under-hood automotive deployment without forced cooling |
| IR @ VWM | <1 µA - ultra-low reverse leakage preserves system efficiency and battery life in always-on circuits |
| Response time | <1.0 ps - enables suppression of ESD and fast-rising transients before sensitive circuitry reacts |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, single-die unidirectional configuration. Cathode indicated by molded band; anode and cathode terminals are axially aligned along the body axis.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (A) | Low-side reference terminal | Connected to ground or low-voltage return path; completes clamping loop during positive transients |
| Cathode (K) | High-side surge input terminal | Connected to protected line (e.g., 188 V rail); conducts avalanche current to ground when VAK ≥ VBR |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive under-hood applications including temperature cycling, humidity, and mechanical shock per JESD22 |
| Glass passivated junction | Enhances long-term reliability and moisture resistance vs. epoxy-passivated alternatives; supports J-STD-020 Level 1 MSL |
| ISO 7637-2 compliance | Guarantees robustness against real-world automotive transients: Pulse 1 (load dump), Pulse 2a/2b (switching), Pulse 3a/3b (line impedance coupling) |
| Matte tin-plated leads | Ensures solderability per J-STD-002 and eliminates whisker growth risk per JESD201 Class 2 |
| UL 94V-0 molding compound | Provides flame-retardant housing essential for automotive and industrial safety-critical assemblies |
Applications
| Automotive On-Board DC/DC Converter | Industrial SMPS Input Stage |
|---|---|
Use Scenario: Protects 188 V intermediate bus in 48 V–188 V isolated DC/DC converters used in ADAS domain controllers and gateway ECUs. IC Role / Device Role / Timing Role: Unidirectional TVS placed across primary-side input capacitor to clamp load-dump transients and ISO 7637-2 Pulse 1 surges. Use Value: Limits voltage excursion to ≤328 V during 400 W pulses, preventing MOSFET gate oxide failure and controller latch-up. | Use Scenario: Safeguards front-end rectifier and bulk capacitor in high-voltage industrial switch-mode power supplies operating near 188 V DC. IC Role / Device Role / Timing Role: Standoff-rated transient suppressor installed between AC-DC output and downstream PFC stage to absorb line-induced spikes. Use Value: Withstands repetitive 10/1000 µs surges up to 400 W while maintaining <1 µA leakage, minimizing standby power loss. |
| Telecom Power Shelf Protection | Rail Voltage Monitoring Interface |
Use Scenario: Shields distributed 188 V telecom power shelf outputs feeding remote radio units (RRUs) in 5G base stations. IC Role / Device Role / Timing Role: Primary surge arrestor on secondary-side distribution bus, coordinated with upstream MOVs and downstream polyfuses. Use Value: Fast <1 ps response ensures clamping before transient propagates to sensitive RF amplifiers and clock modules. | Use Scenario: Guards analog input of voltage supervisor IC monitoring 188 V rail integrity in battery management systems (BMS) for energy storage. IC Role / Device Role / Timing Role: Low-leakage protector placed ahead of precision resistor divider to prevent ESD damage to ADC reference path. Use Value: Sub-1 µA IR at 188 V avoids measurement offset drift; DO-214AC footprint allows compact placement near sensor interface. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ188CH | Bidirectional variant; same VWM (188 V), VBR (209–255 V), VC (344 V), but conducts in both polarities | Required where reverse-polarity transients or AC-coupled signals exist; unsuitable for DC-only unidirectional rails | Select SMAJ188CH only if bidirectional protection is mandated by system-level surge test plan |
| SMBJ188AH | Same electrical specs but in larger DO-214AA (SMB) package; 600 W PPPM rating (vs. 400 W) | Higher power handling suits higher-energy environments; requires PCB layout change due to larger footprint and pitch | Choose SMBJ188AH when surge energy exceeds 400 W or thermal dissipation demands larger copper area |
Compared with SMAJ188CH and SMBJ188AH, the SMAJ188AH offers optimal space-constrained unidirectional protection at 400 W in DO-214AC, balancing AEC-Q101 reliability, low leakage, and automotive transient compliance without over-specifying package size or bidirectional capability.
Availability
SMAJ188AH is available at Aetrix Electronics and suitable for automotive on-board DC/DC converters, industrial SMPS input stages, and telecom power shelf protection requiring stable component supply and full traceability.
Supply support for SMAJ188AH 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 Taiwanese semiconductor manufacturer specializing in discrete power devices, TVS diodes, and rectifiers for automotive and industrial markets.
The SMAJ series was developed specifically for AEC-Q101-compliant transient suppression in harsh-environment DC power systems, emphasizing low leakage, fast response, and ISO 7637-2 immunity.
FAQ
What is the clamping voltage of SMAJ188AH under a 10/1000 µs surge?
The SMAJ188AH has a maximum clamping voltage (VC) of 328 V when subjected to its rated peak impulse current (IPPM) of 0.9 A using the standardized 10/1000 µs waveform. This value is measured per Figure 5 in the official datasheet and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ188AH maintains this clamping performance across its specified operating temperature range.
Is SMAJ188AH suitable for bidirectional surge protection?
No, SMAJ188AH is a unidirectional TVS diode intended for DC rail protection where transients occur only in one polarity. For bidirectional applications - such as AC lines or systems requiring reverse-polarity transient suppression - the SMAJ188CH variant must be used. SMAJ188AH's cathode band marking and electrical specifications confirm its unidirectional conduction path; using it in reverse-biased configurations risks permanent breakdown.
Does SMAJ188AH meet automotive qualification standards?
Yes, SMAJ188AH is AEC-Q101 qualified and explicitly tested to meet ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b transient immunity requirements. Its construction - including glass-passivated junction, matte tin-plated leads compliant with JESD201 Class 2, and UL 94V-0 molding compound - satisfies automotive under-hood environmental stress conditions. TSC documentation confirms full AEC-Q101 certification for the SMAJx(A)H family.
What is the maximum steady-state power dissipation for SMAJ188AH?
The SMAJ188AH has a steady-state power dissipation (PD) rating of 1 W at 25 °C ambient temperature. This value applies to continuous DC or low-frequency reverse-bias conditions and must be derated linearly above 25 °C per the pulse derating curve in Figure 2 of the datasheet. Unlike its 400 W peak pulse rating, PD = 1 W reflects thermal equilibrium limits under non-transient operating conditions.
How does SMAJ188AH compare to SMAJ188H in terms of breakdown voltage?
SMAJ188AH specifies a tighter breakdown voltage range of 209–231 V (min–max) at 1 mA test current, whereas SMAJ188H is rated 209–255 V. This narrower VBR window improves design predictability for clamping threshold alignment in safety-critical systems. Both share identical VWM (188 V), VC (328 V vs. 344 V), and PPPM (400 W), making SMAJ188AH preferable where consistent avalanche onset is required.
SMAJ188AH 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:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 188V
- Voltage - Breakdown (Min):
- 209V
- Voltage - Clamping (Max) @ Ipp:
- 328V
- Current - Peak Pulse (10/1000µs):
- 900mA
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ188AH FAQ
1.How can I place an order for SMAJ188AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ188AH 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 SMAJ188AH reliable?
The price and inventory of SMAJ188AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ188AH is usually 5 days.
3.What payment methods are accepted for SMAJ188AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ188AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ188AH?
SMAJ188AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ188AH 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 SMAJ188AH?
For technical support, including SMAJ188AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ188AH requirements.
6.How does Aetrix verify that SMAJ188AH is sourced from the original manufacturer or authorized distributors?
All SMAJ188AH 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 SMAJ188AH meets industry standards.
7.What is the process for return or replacement of SMAJ188AH?
All SMAJ188AH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ188AH, 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 SMAJ188AH part is unused and in its original packaging.
Return procedure for SMAJ188AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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