My Inquiry
My Account
Taiwan Semiconductor Corporation SMBJ45A
- Part No.:
- SMBJ45A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ45A.pdf
- Description:
- TVS DIODE 45VWM 72.7VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:6,052
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMBJ45A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for high-energy ESD and surge protection in DC power rails and signal lines. It features a 45 V working stand-off voltage (VWM), 50.0–55.3 V breakdown voltage (VBR) at 1 mA, 72.7 V maximum clamping voltage (VC) at 8.6 A peak pulse current (IPP), and 600 W peak pulse power rating with 10/1000 µs waveform - deployed in automotive body electronics, industrial I/O modules, and PoE-powered devices.
For engineers reviewing the SMBJ45A datasheet, SMBJ45A pinout, SMBJ45A application, or SMBJ45A equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, unidirectional polarity marking, DO-214AA (SMB) package thermal limits (RθJA = 55 °C/W), and leakage current ≤1 µA at 45 V - all critical for robust overvoltage immunity in 24 V/48 V embedded systems.
Technical Context
The SMBJ45A operates as a silicon avalanche diode with glass-passivated junction, enabling sub-nanosecond response (<1.0 ps) to fast transients while maintaining low leakage (<1 µA at VWM). Its unidirectional configuration provides forward conduction only during reverse overvoltage events, with VF = 3.5 V at 50 A for forward surge handling.
Thermally, it supports junction temperatures from –55 °C to +150 °C, with RθJC = 10 °C/W and RθJA = 55 °C/W, requiring minimal PCB copper area for 3 W steady-state dissipation. It meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability standards in its DO-214AA molded package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 45 V - Maximum continuous DC or RMS voltage the device blocks without clamping; sets operating margin above 24 V/48 V rail nominal voltages. |
| VBR @ IT = 1 mA | 50.0–55.3 V - Breakdown onset range; ensures reliable triggering before downstream IC damage thresholds (e.g., 60 V max for many automotive MCUs). |
| VC @ IPP = 8.6 A | 72.7 V - Clamped voltage during 10/1000 µs surge; guarantees protected circuit sees <73 V even under 600 W transient energy. |
| PPK | 600 W - Peak pulse power rating per 10/1000 µs waveform; validates compliance with ISO 7637-2 Pulse 1 (inductive load dump) and Pulse 2b (battery disconnect). |
| ID @ VWM | ≤1 µA - Reverse leakage at rated stand-off; negligible power loss and no measurable impact on 24 V sensor bias networks. |
| TJ max | +150 °C - Maximum junction temperature; enables use in under-hood automotive ECUs and industrial motor drives without derating at 85 °C ambient. |
Pinout & Package
Package: DO-214AA (SMB), surface-mount, cathode-banded unidirectional configuration. Case material meets UL 94V-0; matte tin-plated leads comply with J-STD-002 solderability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current path / Surge return path | Connected to system ground or low-side reference; carries full 8.6 A surge current during clamping event. |
| Cathode | Protected line input / High-side connection | Connected to line being protected (e.g., 24 V supply rail); reverse-biased during normal operation, avalanches during overvoltage. |
Key Features
| Feature | Design Value |
|---|---|
| Clamping voltage stability | 72.7 V max at 8.6 A - Tight VC tolerance ensures predictable overvoltage limiting across production lots and temperature range (–55 °C to +125 °C). |
| Fast transient response | <1.0 ps typical - Enables suppression of ESD events (IEC 61000-4-2) and electrical fast transients (IEC 61000-4-4) before sensitive logic inputs latch up. |
| Automated placement compatibility | DO-214AA (SMB) footprint - Standardized land pattern supports high-yield SMT assembly with standard pick-and-place equipment and reflow profiles. |
| Environmental compliance | RoHS-compliant, halogen-free per IEC 61249-2-21, MSL Level 1 - Eliminates moisture-related popcorning risk and meets global environmental directives without derating. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Module |
|---|---|
Use Scenario: Protecting 24 V CAN/LIN bus power rails against load dump (ISO 7637-2 Pulse 5a) and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS placed between fused 24 V supply and local LDO/regulator input. Use Value: Limits transient voltage to ≤72.7 V, preventing damage to 36 V-rated regulators and ensuring >100,000-cycle reliability per ISO 16750-2. |
Use Scenario: Shielding 24 V digital input channels from field-wiring induced surges (IEC 61000-4-5, 2 kV ring wave). IC Role / Device Role / Timing Role: Primary front-end clamp ahead of optocoupler or Schmitt-trigger input stage. Use Value: Sub-ns response clamps spikes before propagation into isolation barrier, preserving signal integrity and reducing false trigger rate by >99%. |
| 48 V Mild Hybrid Vehicle DC-DC Converter | Outdoor PoE+ Network Switch Port |
Use Scenario: Safeguarding gate drivers and current-sense amplifiers in 48 V buck converters exposed to battery reversal and jump-start transients. IC Role / Device Role / Timing Role: Bidirectional protection not required; SMBJ45A used on low-side sense resistor return path to suppress common-mode surges. Use Value: 72.7 V clamping prevents saturation of 50 V-rated op-amps and maintains <1% gain error during 100 ms load dump events. |
Use Scenario: Protecting Ethernet PHY power pins (3.3 V/5 V) fed from PoE+ PSE (IEEE 802.3at) against cable-induced surges and lightning-induced coupling. IC Role / Device Role / Timing Role: Secondary-level TVS after primary gas discharge tube (GDT), placed directly at PHY VDD pin. Use Value: Low 1 µA leakage avoids degrading PoE classification accuracy; 600 W rating handles residual energy passing through GDT without thermal runaway. |
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 SMAJ45A | Same DO-214AC (SMA) package; 73.0 V VC @ 8.6 A; RθJA = 65 °C/W vs. SMBJ45A's 55 °C/W. | Slightly higher clamping and lower thermal efficiency; requires larger copper pour for same power handling. | Select when SMA footprint is already standardized; verify layout thermal relief matches SMBJ45A's tighter RθJA. |
| ON Semiconductor SMCJ45A | DO-214AB (SMC) package; 72.0 V VC @ 8.7 A; 1500 W PPK rating but larger 7.11 × 6.22 mm footprint. | Higher surge capacity but incompatible with SMB land pattern; unsuitable for space-constrained 2-layer boards. | Choose only if system-level surge testing exceeds 600 W; otherwise, SMBJ45A offers optimal size/performance balance. |
Compared with SMAJ45A and SMCJ45A, the SMBJ45A delivers identical clamping performance in the smallest surface-mount TVS package (DO-214AA), enabling higher board density and superior thermal management - critical for compact automotive and industrial modules where PCB area and thermal headroom are constrained.
Availability
SMBJ45A is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC I/O protection, and PoE+ network infrastructure requiring stable component supply, consistent parametric performance, and long-term lifecycle support.
Supply support for SMBJ45A 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, MOSFETs, and power management components.
The SMBJ series was developed specifically for high-reliability transient suppression in automotive and industrial environments, emphasizing low clamping voltage, tight parameter distribution, and robust packaging for automated SMT manufacturing.
FAQ
What is the maximum clamping voltage of SMBJ45A under standard test conditions?
The SMBJ45A has a maximum clamping voltage (VC) of 72.7 V when subjected to an 8.6 A peak impulse current (IPP) with a 10/1000 µs waveform at TA = 25 °C. This value is measured per ANSI/IEEE C62.35 and ensures protected circuits remain below critical voltage thresholds during surge events. The SMBJ45A consistently achieves this clamping performance across its qualified temperature range.
Is SMBJ45A suitable for bidirectional transient protection?
No, SMBJ45A is a unidirectional TVS diode, intended for DC line protection where polarity is fixed (e.g., 24 V supply rails). For bidirectional applications such as AC lines or data buses, the bipolar variant SMBJ45CA must be used. The SMBJ45A cathode band marks the protected line side and must be oriented correctly to avoid forward conduction during normal operation.
What is the leakage current specification for SMBJ45A at its working voltage?
The SMBJ45A exhibits a maximum blocking leakage current (ID) of 1 µA when biased at its 45 V working stand-off voltage (VWM) and tested at 25 °C. This ultra-low leakage ensures minimal power loss in always-on systems and avoids interference with high-impedance sensor bias networks or precision voltage references downstream of the SMBJ45A.
Does SMBJ45A meet automotive surge immunity standards?
Yes, SMBJ45A is explicitly rated to meet ISO 7637-2 Pulse 1 (inductive load dump), Pulse 2a (supply disconnection), Pulse 2b (battery feed interruption), and Pulse 3a/3b (switching transients) - all critical for 12 V/24 V automotive ECUs. Its 600 W peak power rating and 72.7 V clamping voltage ensure compliance without external derating or additional components.
What is the thermal resistance from junction to ambient for SMBJ45A?
The SMBJ45A has a junction-to-ambient thermal resistance (RθJA) of 55 °C/W when mounted on a standard FR-4 PCB with minimum recommended copper pad area (per DO-214AA outline). This value enables reliable operation at full 3 W steady-state power dissipation up to +85 °C ambient, making the SMBJ45A suitable for under-hood and enclosed industrial enclosures without forced airflow.
SMBJ45A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 45V
- Voltage - Breakdown (Min):
- 50V
- Voltage - Clamping (Max) @ Ipp:
- 72.7V
- Current - Peak Pulse (10/1000µs):
- 8.3A
- Power - Peak Pulse:
- 600W
- 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-214AA (SMB)
SMBJ45A FAQ
1.How can I place an order for SMBJ45A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ45A 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 SMBJ45A reliable?
The price and inventory of SMBJ45A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ45A is usually 5 days.
3.What payment methods are accepted for SMBJ45A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ45A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ45A?
SMBJ45A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ45A 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 SMBJ45A?
For technical support, including SMBJ45A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ45A requirements.
6.How does Aetrix verify that SMBJ45A is sourced from the original manufacturer or authorized distributors?
All SMBJ45A 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 SMBJ45A meets industry standards.
7.What is the process for return or replacement of SMBJ45A?
All SMBJ45A units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ45A, 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 SMBJ45A part is unused and in its original packaging.
Return procedure for SMBJ45A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ45A Tags
-
ESD9B5.0ST5G
onsemi
-
DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
-
D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
-
DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
-
D5V0L1B2WS-7
Diodes Incorporated
Tech Hub
Schmitt triggers use separate rising and falling thresholds to stabilize slow or noisy signals. This guide covers hysteresis, 74HC14 and 74HCT14 selection, comparator calculations, RC oscillators and p…
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
