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Taiwan Semiconductor Corporation SMAJ20CH
- Part No.:
- SMAJ20CH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ20CH.pdf
- Description:
- TVS DIODE 20VWM 35.8VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:8,599
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Product details
Overview
SMAJ20CH from Taiwan Semiconductor is a unidirectional 400W transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for robust overvoltage protection in automotive and industrial DC power lines. It features a 20V working stand-off voltage (VWM), 22.2–24.5V breakdown voltage (VBR), 32.4V maximum clamping voltage (VC) at 12.3A peak pulse current, and AEC-Q101 qualification for automotive-grade reliability.
For engineers reviewing the SMAJ20CH datasheet, SMAJ20CH pinout, SMAJ20CH application, or SMAJ20CH equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, moisture sensitivity level (MSL 1), and compatibility with automated SMT placement on 12V–24V board-level power rails.
Technical Context
The SMAJ20CH operates as a unidirectional avalanche diode with glass-passivated junction, delivering sub-1ps response time from 0 V to VBR min. Its single-die DO-214AC construction supports bidirectional surge suppression only when paired with complementary polarity devices - the "CH" suffix confirms unidirectional configuration with cathode band marking.
It meets ISO 7637-2 immunity requirements for automotive electronics, with 400W peak pulse power (10/1000μs waveform) derated above 25°C and steady-state power dissipation of 1W. Junction temperature range spans –55°C to +150°C, enabling deployment in under-hood and industrial control environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - Maximum continuous reverse voltage before leakage exceeds 1 µA; sets operating margin for 12V/24V systems. |
| VBR @ IT=1mA | 22.2–24.5 V - Breakdown threshold at test current; ensures reliable turn-on during transients without false triggering. |
| VC @ IPPM | 32.4 V at 12.3 A - Clamped voltage during 10/1000μs surge; limits downstream IC stress below 33V absolute max ratings. |
| PPPM | 400 W (10/1000μs) - Peak surge energy handling; sufficient for ISO 7637-2 Pulse 1 (inductive load dump) and Pulse 2b (battery disconnect). |
| IR @ VWM | <1 µA - Ultra-low leakage preserves battery life in always-on automotive modules and low-power IoT nodes. |
| TJ Range | –55°C to +150°C - Enables use in engine control units (ECUs), body controllers, and industrial motor drives without thermal derating. |
Pinout & Package
DO-214AC (SMA) surface-mount package: molded epoxy case rated UL 94V-0, matte tin-plated leads compliant with J-STD-002 solderability, polarity indicated by cathode band. Weight: 0.060 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input/Line side (non-banded end) | Connected to protected line (e.g., 24V rail); conducts during reverse surge when cathode is held higher. |
| Cathode | Clamp/Return side (banded end) | Connected to ground or low-impedance return path; defines unidirectional conduction direction and clamping reference. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including engine management, ADAS sensors, and infotainment power supplies. |
| Glass passivated junction | Ensures stable VBR over lifetime and resistance to humidity-induced parameter drift in harsh environments. |
| Fast response time <1 ps | Clamps ESD and fast transients (e.g., ISO 10605, IEC 61000-4-2) before sensitive logic or analog circuitry is damaged. |
| Meets ISO 7637-2 Pulse 1/2a/2b/3a/3b | Provides system-level immunity against load dump, supply interruption, and capacitive coupling events in 12V/24V vehicle networks. |
Applications
| Automotive Body Control Module (BCM) | Industrial 24V PLC Input Stage |
|---|---|
Use Scenario: Protecting microcontroller GPIOs and CAN transceiver power pins from load dump and battery reversal transients in BCMs. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between 24V supply rail and local ground plane. Use Value: Limits clamped voltage to 32.4V, keeping downstream 3.3V/5V regulators and CAN PHYs within safe operating area during 100V/500ms load dump events. | Use Scenario: Safeguarding digital input optocouplers and signal conditioning circuits in programmable logic controller (PLC) field-side terminals. IC Role / Device Role / Timing Role: Primary overvoltage protector on 24V DC sensor input lines exposed to inductive kickback from solenoids and relays. Use Value: Withstands 400W surges per IEC 61000-4-5 (10/1000μs) while maintaining <1µA leakage to avoid false triggering of high-impedance inputs. |
| LED Driver Power Supply | On-board DC/DC Converter Input |
Use Scenario: Suppressing switching noise and line surges in constant-current LED drivers used in commercial lighting fixtures. IC Role / Device Role / Timing Role: Input-side TVS across bulk capacitor terminals to absorb MOSFET switching spikes and lightning-induced surges. Use Value: Clamps transients to ≤32.4V within <1ps, preventing overvoltage failure of primary-side PWM controllers and gate drivers. | Use Scenario: Input rail protection for buck converters powering FPGAs or DSPs in embedded computing modules. IC Role / Device Role / Timing Role: First-line transient suppressor upstream of input filter and converter IC, referenced to system ground. Use Value: Enables compliance with EN 55032 Class B conducted emissions by limiting high-frequency ringing amplitude at converter input. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ20AHE3/5BT | Same VWM (20V), lower VBR min (22.2V vs. 22.2V), identical VC (32.4V), same DO-214AC package, Vishay AEC-Q101 qualified. | No functional difference; validated for identical ISO 7637-2 pulses and automotive temperature profiles. | Select SMAJ20AHE3/5BT if dual-sourcing or long-term availability from alternate franchise distributor is required. |
| P6SMB20AH | Same VWM (20V), slightly higher VC (34.0V at 11.7A), 600W rating (10/1000μs), DO-214AA (SMB) package - 1.6mm wider than SMA. | Larger footprint requires PCB layout change; higher clamping voltage may exceed downstream IC limits in tight-margin designs. | Choose P6SMB20AH only when higher peak power headroom is needed and board space allows SMB footprint. |
Compared with SMAJ20CH, SMAJ20AHE3/5BT offers identical electrical and mechanical specs with second-source assurance, while P6SMB20AH trades smaller DO-214AC size for higher power and looser clamping - requiring layout revision and voltage margin review.
Availability
SMAJ20CH is available at Aetrix Electronics and suitable for automotive body electronics, industrial 24V PLCs, LED driver power supplies, and on-board DC/DC converter inputs requiring stable component supply across extended temperature ranges and high-reliability production cycles.
Supply support for SMAJ20CH 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 semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs for automotive, industrial, and consumer markets.
The SMAJ series was developed specifically for AEC-Q101-compliant transient protection in 12V/24V automotive and ruggedized industrial power systems, emphasizing low clamping, fast response, and MSL-1 manufacturability.
FAQ
What is the clamping voltage of the SMAJ20CH under a 10/1000μs surge?
The SMAJ20CH has a maximum clamping voltage (VC) of 32.4 V at 12.3 A peak pulse current under the standardized 10/1000μs waveform. This value is measured per Figure 5 in the official datasheet and ensures protected circuits remain below critical overvoltage thresholds during ISO 7637-2 Pulse 1 and Pulse 2b events. The SMAJ20CH maintains this clamping performance across its full operating temperature range.
Is the SMAJ20CH suitable for bidirectional transient suppression?
No, the SMAJ20CH is a unidirectional TVS diode, indicated by the "CH" suffix and cathode band marking. For bidirectional protection, Taiwan Semiconductor specifies separate parts with "CAH" suffix (e.g., SMAJ20CAH). Using SMAJ20CH in reverse-biased configurations risks permanent damage due to lack of forward surge capability in the reverse direction.
Does the SMAJ20CH meet automotive qualification standards?
Yes, the SMAJ20CH is AEC-Q101 qualified and explicitly tested to meet ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b immunity requirements. Its DO-214AC package carries MSL Level 1 rating per J-STD-020, and it operates reliably from –55°C to +150°C - fulfilling core environmental and reliability demands for automotive ECUs, body control modules, and ADAS power domains.
What is the maximum steady-state power dissipation for the SMAJ20CH?
The SMAJ20CH has a maximum steady-state power dissipation (PD) of 1 W at 25°C ambient, as specified in the Absolute Maximum Ratings table. This rating applies to continuous DC or low-frequency reverse bias conditions and must be thermally derated linearly above 25°C per the Pulse Derating Curve (Figure 2). At 100°C ambient, usable PD drops to approximately 0.5 W.
How does the SMAJ20CH compare to the SMAJ20AH variant?
The SMAJ20CH and SMAJ20AH share identical VWM (20 V), IR (<1 µA), and TJ range (–55°C to +150°C), but differ in breakdown voltage: SMAJ20CH has VBR min/max of 22.2–24.5 V, while SMAJ20AH is 22.2–27.1 V. Both deliver the same 32.4 V clamping voltage at rated current. The "CH" variant offers tighter VBR tolerance, improving consistency in precision clamp applications.
SMAJ20CH 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):
- 20V
- Voltage - Breakdown (Min):
- 22.2V
- Voltage - Clamping (Max) @ Ipp:
- 35.8V
- Current - Peak Pulse (10/1000µs):
- 11.2A
- 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)
SMAJ20CH FAQ
1.How can I place an order for SMAJ20CH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ20CH 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 SMAJ20CH reliable?
The price and inventory of SMAJ20CH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ20CH is usually 5 days.
3.What payment methods are accepted for SMAJ20CH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ20CH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ20CH?
SMAJ20CH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ20CH 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 SMAJ20CH?
For technical support, including SMAJ20CH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ20CH requirements.
6.How does Aetrix verify that SMAJ20CH is sourced from the original manufacturer or authorized distributors?
All SMAJ20CH 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 SMAJ20CH meets industry standards.
7.What is the process for return or replacement of SMAJ20CH?
All SMAJ20CH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ20CH, 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 SMAJ20CH part is unused and in its original packaging.
Return procedure for SMAJ20CH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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