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Taiwan Semiconductor Corporation SMAJ48H
- Part No.:
- SMAJ48H
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ48H.pdf
- Description:
- TVS DIODE 48VWM 85.5VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:3,193
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Product details
Overview
SMAJ48H from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for clamping fast transients in DC power rails. It features 48 V working stand-off voltage (VWM), 53.3–65.1 V breakdown voltage (VBR) at 1 mA test current, and clamps to ≤85.5 V at 4.7 A peak impulse current under 10/1000 µs waveform - suitable for protecting automotive DC/DC converters and industrial SMPS inputs.
For engineers reviewing the SMAJ48H datasheet, SMAJ48H pinout, SMAJ48H application, or SMAJ48H equivalent, key selection criteria include its AEC-Q101 qualification, 400 W peak pulse power rating (10/1000 µs), <1 ps response time, low leakage (<1 µA @ 48 V), and ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance for automotive load-dump and switching surge immunity.
Technical Context
The SMAJ48H operates as a unidirectional avalanche diode with glass-passivated junction, optimized for rapid clamping of voltage spikes on positive-rail lines. Its 150 °C maximum junction temperature and -55 °C to +150 °C operating range support under-hood automotive and industrial environments.
It delivers 400 W peak pulse power per 10/1000 µs waveform up to 78 V VWM; above that, rating drops to 300 W. The device meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements, with matte tin-plated leads compliant to J-STD-002 solderability standards.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 48 V - Maximum continuous reverse voltage before significant leakage; sets safe operating margin for 48 V nominal systems. |
| VBR min/max | 53.3 V / 65.1 V @ 1 mA - Confirmed avalanche onset range; ensures reliable triggering above system overvoltage thresholds. |
| VC @ IPPM | ≤85.5 V @ 4.7 A - Clamped voltage during 10/1000 µs surge; defines worst-case rail excursion seen by downstream ICs. |
| PPPM | 400 W (10/1000 µs) - Peak transient energy handling capacity; sufficient for ISO 7637-2 Pulse 1 (inductive switch-off) and Pulse 2b (battery dump). |
| IR @ VWM | <1 µA - Negligible standby leakage at rated stand-off; avoids battery drain in always-on automotive modules. |
| TJ max | +150 °C - Enables placement near hot components (e.g., MOSFETs, inductors) without thermal derating concerns. |
| Package | DO-214AC (SMA) - Standardized SMT outline with cathode band marking; compatible with automated pick-and-place and reflow profiles. |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with two coplanar leads; polarity indicated by cathode band (cathode = marked end). Lead finish: matte tin, solderable per J-STD-002. Weight: 0.060 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference node | Connected to ground or return path; forms clamping path when cathode is at higher potential. |
| Cathode | Protected line input | Connected to the rail being protected (e.g., 48 V supply); conducts during overvoltage to shunt current to ground. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD - required for engine control, body electronics, and ADAS modules. |
| Glass-passivated junction | Stable, low-noise avalanche behavior across life cycle; prevents parameter drift under humidity and thermal stress. |
| Fast response time <1 ps | Clamps transients before sensitive logic or analog circuitry responds - critical for protecting CAN transceivers and microcontrollers. |
| ISO 7637-2 compliance | Tested against Pulse 1 (inductive load disconnect), Pulse 2a (supply interruption), Pulse 2b (battery dump), and Pulses 3a/3b (switching noise) - full automotive EMC readiness. |
| Moisture sensitivity level 1 | No floor-life limitation or bake requirement before reflow; simplifies manufacturing and inventory management. |
Applications
| Automotive DC/DC Converter Input Protection | Industrial SMPS Surge Suppression |
|---|---|
Use Scenario: Protecting 48 V input stage of buck converter in vehicle infotainment head unit exposed to load-dump events per ISO 7637-2 Pulse 5a. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between 48 V rail and chassis ground, triggered within picoseconds to limit voltage to ≤85.5 V. Use Value: Prevents damage to primary-side controller ICs (e.g., UCC28070) and gate drivers during 120 V/100 ms transients. | Use Scenario: Safeguarding 48 V auxiliary supply in programmable logic controller (PLC) backplane against switching surges from relay coils and motor drives. IC Role / Device Role / Timing Role: Standoff protection element absorbing repetitive 400 W pulses without degradation; mounted upstream of input filter capacitors. Use Value: Eliminates need for external crowbar circuits or redundant fusing while maintaining >100,000 surge cycles lifetime. |
| LED Driver Power Rail Clamp | On-Board Charger (OBC) Auxiliary Supply |
Use Scenario: Securing constant-current LED driver input in commercial lighting fixture subjected to lightning-induced surges on long cable runs. IC Role / Device Role / Timing Role: Primary overvoltage suppression device on 48 V bus, operating in parallel with bulk capacitance to absorb fast-edge transients. Use Value: Maintains LED string integrity by limiting rail overshoot to <86 V - below MOSFET VDS(max) and driver IC absolute maximum ratings. | Use Scenario: Protecting 48 V auxiliary supply rail in electric vehicle on-board charger during high-voltage battery connection/disconnection events. IC Role / Device Role / Timing Role: Fast-acting clamping diode on isolated 48 V secondary side, coordinated with primary-side TVS and common-mode chokes. Use Value: Ensures uninterrupted operation of MCU, CAN interface, and gate drivers during 100 V/40 ms load-dump transients per ISO 16750-2. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ48AH | Narrower VBR range (53.3–58.9 V vs. 53.3–65.1 V); tighter tolerance improves clamping predictability but reduces margin for VBR drift over temperature/life. | Better suited for precision-clamp designs where VC variation must be minimized; less tolerant of aging-related VBR increase. | Select SMAJ48AH when system-level testing confirms tighter VBR distribution improves robustness; otherwise SMAJ48H offers broader process margin. |
| SMBJ48A | Same VWM/VBR specs but in larger DO-214AA (SMB) package; 600 W peak power rating (10/1000 µs) vs. 400 W. | Higher power handling supports longer-duration transients (e.g., extended load-dump); requires larger PCB footprint and different pad layout. | Choose SMBJ48A only if surge test profiles exceed 400 W capability or if thermal dissipation constraints favor larger package. |
Compared with SMAJ48AH and SMBJ48A, the SMAJ48H balances cost, board space, and robustness for mainstream 48 V automotive and industrial applications - delivering verified AEC-Q101 performance in the smallest standardized SMT TVS outline without over-specifying power or tolerance.
Availability
SMAJ48H is available at Aetrix Electronics and suitable for automotive DC/DC converters, industrial SMPS units, and LED driver power rails requiring stable component supply with AEC-Q101 qualification and ISO 7637-2 compliance.
Supply support for SMAJ48H 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, rectifiers, and MOSFETs for automotive, industrial, and consumer markets.
The SMAJ series was developed specifically for AEC-Q101-compliant transient suppression in compact SMT form factors, targeting 12 V–188 V systems where reliability, fast response, and standardized packaging are mandatory.
FAQ
What is the maximum clamping voltage of the SMAJ48H under standard test conditions?
The SMAJ48H has a maximum clamping voltage (VC) of 85.5 V when subjected to its rated peak impulse current of 4.7 A using the 10/1000 µs waveform. This value is measured at TA = 25°C and represents the upper bound of voltage seen by protected circuitry during a defined transient event. The SMAJ48H maintains this clamping performance across its specified operating temperature range, making it suitable for demanding automotive and industrial environments where consistent overvoltage protection is critical.
Is the SMAJ48H unidirectional or bidirectional, and how is polarity identified?
The SMAJ48H is a unidirectional TVS diode, intended for use on positive-rail protection with cathode connected to the protected line and anode grounded. Polarity is marked by a distinct cathode band on the DO-214AC (SMA) package body - consistent with industry-standard diode marking conventions. Bidirectional variants in the same family use CH or CAH suffixes (e.g., SMAJ48CH), which are not interchangeable with the SMAJ48H due to differing electrical symmetry and clamping behavior in both directions.
Does the SMAJ48H meet automotive qualification standards?
Yes, the SMAJ48H is AEC-Q101 qualified and tested per ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b for automotive electromagnetic compatibility. It also complies with JESD201 Class 2 whisker resistance, J-STD-020 moisture sensitivity level 1, and RoHS/halogen-free requirements per IEC 61249-2-21. These qualifications confirm its suitability for under-hood and cabin-mounted electronic control units where long-term reliability under thermal, mechanical, and electrical stress is mandatory.
What is the peak pulse power rating of the SMAJ48H, and how does it vary with pulse duration?
The SMAJ48H is rated for 400 W peak pulse power with the standard 10/1000 µs double-exponential waveform. This rating applies up to 78 V VWM; for devices with VWM > 78 V (e.g., SMAJ85H), the rating reduces to 300 W. The device's pulse derating curve (Fig.2 in datasheet) shows linear reduction above TA = 25°C - at 125°C ambient, its usable peak power drops to approximately 200 W. Pulse width deviations from 10/1000 µs require recalculating IPPM using the peak pulse power rating curve (Fig.1).
Can the SMAJ48H be used in bidirectional signal-line protection?
No, the SMAJ48H is strictly unidirectional and must not be used for bidirectional signal-line protection such as RS-485, CAN, or USB data lines. Its asymmetrical IV characteristics provide clamping only for positive transients on the cathode side. For bidirectional protection, TSC offers dedicated variants like SMAJ48CH (with CH suffix) or recommends purpose-built low-capacitance TVS arrays. Using SMAJ48H on AC-coupled or differential signal paths risks forward conduction, signal distortion, or failure to suppress negative-going transients.
SMAJ48H 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):
- 48V
- Voltage - Breakdown (Min):
- 53.3V
- Voltage - Clamping (Max) @ Ipp:
- 85.5V
- Current - Peak Pulse (10/1000µs):
- 4.7A
- 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)
SMAJ48H FAQ
1.How can I place an order for SMAJ48H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ48H 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 SMAJ48H reliable?
The price and inventory of SMAJ48H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ48H is usually 5 days.
3.What payment methods are accepted for SMAJ48H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ48H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ48H?
SMAJ48H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ48H 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 SMAJ48H?
For technical support, including SMAJ48H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ48H requirements.
6.How does Aetrix verify that SMAJ48H is sourced from the original manufacturer or authorized distributors?
All SMAJ48H 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 SMAJ48H meets industry standards.
7.What is the process for return or replacement of SMAJ48H?
All SMAJ48H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ48H, 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 SMAJ48H part is unused and in its original packaging.
Return procedure for SMAJ48H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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