1SMC12AT3G - 12V 1500W TVS Diode SMC | Littelfuse
Teilenummer: 1SMC12AT3G ✓ Aktiv| Menge | Stückpreis | Gesamt |
|---|---|---|
| 1 | $0.62 | $0,62 |
| 10 | $0.52 | $5,20 |
| 100 | $0.38 | $38,00 |
| 500 | $0.29 | $145,00 |
| 1.000 | $0.24 | $240,00 |
1SMC12AT3G Übersicht
A TVS diode is a specialized semiconductor protection device that operates in avalanche breakdown under reverse-bias stress, diverting transient energy away from downstream circuitry within sub-microsecond response times. Sitting at the bottom of the protection hierarchy alongside MOVs, gas discharge tubes, and polymer ESD suppressors, TVS diodes combine fast response, well-defined clamping voltage, and repeatable surge handling - making them the preferred choice for secondary-side protection on DC power rails and signal interfaces.
Key features include a 12 V working standoff voltage, 19.9 V maximum clamping voltage at Ipp = 75.3 A, an excellent clamping ratio, low Zener impedance under breakdown, leakage below 5 uA above 10 V, and a peak forward surge rating suitable for industrial transient environments. The SMC (DO-214AB) molded plastic package offers a void-free thermosetting construction compatible with industry-standard reflow profiles.
Internally the 1SMC12AT3G is a silicon PN-junction Zener structure with a large die optimized for uniform avalanche breakdown across the full junction area. This avoids localized hot spots during high-current 8/20 us or 10/1000 us surge pulses, which is why the part reliably dissipates 1500 W peak power for short durations.
Typical applications are DC power rail protection (12 V systems), automotive load-dump transient suppression, industrial control I/O protection, USB and CAN bus line protection, and protection of MOSFET gate drivers and telecom equipment from induced surge events. The unidirectional polarity suits circuits where a single voltage polarity is present. When designing with this part, ensure PCB pad geometry follows the SMC land pattern (DO-214AB), use wide copper traces to the cathode and anode pads to handle peak surge current, and pair the TVS with a typical upstream fuse or PTC for sustained over-voltage or over-current faults.
Drop-in-Alternativen für 1SMC12AT3G – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
SZ1SMC12AT3G
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
1SMC12AT3
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
SMCJ12A
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
SMCJ12-G
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
1.5SMC12A
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
1SMC5.0AT3G
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
1SMC12AT3G Grenzwerte & elektrische Eigenschaften
| Series | 1SMCxxA |
| Polarity | Unidirectional |
| Working Peak Reverse Voltage (Vrwm) | 12 V |
| Breakdown Voltage (Vbr) | 13.3 V (min) / 14.7 V (max) |
| Maximum Clamping Voltage (Vc) at Ipp | 19.9 V at 75.3 A |
| Peak Pulse Power (Pppm) | 1500 W (10/1000 us) |
| Peak Pulse Current (Ipp) | 75.3 A |
| Reverse Leakage Current (Ir) at Vrwm | < 5 uA (above 10 V) |
| Maximum Operating Junction Temperature | 150 C |
| Minimum Operating Temperature | -65 C |
| Gehäuse | DO-214AB (SMC) |
| Montageart | Surface Mount |
| Pin-Anzahl | 2 |
| MSL-Level | 1 |
| RoHS-Status | Compliant |
1SMC12AT3G Pin-Konfiguration
| Pin 1 | Cathode — Cathode terminal (marked with a colored band on the body) |
| Pin 2 | Anode — Anode terminal |
Typische Anwendungen
1SMC12AT3G ist geeignet für 7 Anwendungs: 12V DC Power Rail Transient Protection, Automotive 12V Bus Load-Dump Protection, USB and CAN Bus Line Protection, Industrial Control I/O Protection, MOSFET Gate and Driver Protection, Telecom Equipment DC Feed Protection, Portable and Battery-Powered Device Protection.
12V DC Power Rail Transient Protection
The 1SMC12AT3G's 12 V Vrwm and 19.9 V clamping voltage at 75.3 A make it an ideal clamp on a 12 V DC distribution rail feeding microcontrollers, FPGAs, and downstream regulators. Placed in shunt across the rail near the connector or board entry, it absorbs inductive kick from relays, motor stall events, and hot-plug transients - events that would otherwise push the rail above the absolute-maximum rating of 20 V. Unlike a fuse, the TVS survives repeated surges and recovers within microseconds, providing continuous protection without service interruption.
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Automotive 12V Bus Load-Dump Protection
Although the standard 1SMC12AT3G is recommended for non-automotive industrial 12 V systems, the SZ1SMC12AT3G automotive variant of the same die protects automotive 12 V buses from load-dump transients up to 35-40 V that occur when an alternator load is suddenly disconnected. With 75.3 A Ipp and 1500 W peak pulse capability, the device clamps the resulting spike inside the 20 V envelope required by sensitive automotive ECUs and infotainment processors. The DO-214AB SMC body dissipates heat effectively even at underhood ambient temperatures up to 125 C.
Empfohlen
USB and CAN Bus Line Protection
USB 2.0, CAN, and RS-485 data lines operating from a 5 V or 12 V reference are vulnerable to ESD and cable-discharge transients exceeding 8 kV. By placing the 1SMC12AT3G from data line to ground (with a series current-limiting resistor for differential lines), the diode clamps incoming surge to 19.9 V before it can punch through to the transceiver. The sub-microsecond response time and 75.3 A Ipp make this a robust solution for industrial USB hubs, PLC communication ports, and on-board CAN interfaces exposed to field wiring.
Empfohlen
Industrial Control I/O Protection
PLC digital inputs, 24 V analog front ends, and factory-automation sensor lines are routinely exposed to high-energy transients from switching of inductive loads (solenoids, contactors, relay coils) sharing the same wiring harness. The 1SMC12AT3G clamps such surges to 19.9 V, well below the 30 V typical abs-max of industrial I/O drivers. Its -65 C to +150 C operating range covers outdoor and factory-floor environments, and the DO-214AB SMC package handles repeated 10/1000 us surge events without derating.
Empfohlen
MOSFET Gate and Driver Protection
Power MOSFETs in 12 V-referenced half-bridges and motor drives can suffer gate-oxide breakdown from drain-voltage transients coupled through Miller capacitance. Putting a 1SMC12AT3G from gate to source (for low-side switches) or from the gate-driver supply to ground clamps these spikes to within the 20 V gate-rating of common MOSFETs. The TVS's 1500 W rating and 75.3 A Ipp comfortably absorb the brief but energetic spikes typical of hard-switched inductive loads.
Empfohlen
Telecom Equipment DC Feed Protection
Telecom racks powered by -48 V systems often use 12 V intermediate rails for plug-in cards, where surge protection per GR-1089 / ITU-T K.20 is required. The 1SMC12AT3G placed across the 12 V rail prevents induced voltage transients from lightning events on outdoor plant wiring from propagating into card-cage backplanes. Its UL recognition and 1500 W surge rating make it a recognized component for telecom front-end protection assemblies.
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Portable and Battery-Powered Device Protection
Battery packs, USB Type-C charging ports, and wearable charging cradles present on a 5-12 V rail can be exposed to ESD during user handling. The 1SMC12AT3G (used in tandem with a lower-voltage TVS for the 5 V portion) protects the charging IC and battery management port from human-body-model ESD events up to 8 kV contact / 15 kV air. Surface-mount SMC packaging enables compact designs, while the 6.86 mm x 3.81 mm footprint allows integration in small-format PCBs used in portable electronics.
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Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für 1SMC12AT3G – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | SZ1SMC12AT3G | 1SMC12AT3 | SMCJ12A | SMCJ12-G | 1.5SMC12A | 1SMC5.0AT3G |
|---|---|---|---|---|---|---|---|
| Brand | Littelfuse | Littelfuse | Littelfuse | Bourns | Comchip | Littelfuse | Littelfuse |
| Package | DO-214AB (SMC) | DO-214AB (SMC) - same | DO-214AB (SMC) - same | DO-214AB (SMC) - same | DO-214AB (SMC) - same | DO-214AB (SMC) - same | DO-214AB (SMC) - same |
| Polarity | Unidirectional | Unidirectional | Unidirectional | Unidirectional | Unidirectional | Unidirectional | Unidirectional |
| Working Voltage (Vrwm) | 12 V | 12 V | 12 V | 12 V | 12 V | 12 V | 5 V (NOT a 12 V substitute) |
| Peak Pulse Power (Pppm) | 1500 W (10/1000 us) | 1500 W | 1500 W | 1500 W | 1500 W | 1500 W | 1500 W |
| Automotive Grade (AEC-Q101) | No | Yes | No | No | No | No | No |
Wichtigste Unterscheidungsmerkmale
- Commercial vs automotive-grade choice in same die (vs. SZ1SMC12AT3G)
- Cross-brand second source on identical footprint (vs. SMCJ12A (Bourns))
- Multiple voltage rails from the same family (vs. 1SMC5.0AT3G)
Designhinweise
Use the JEDEC DO-214AB (SMC) recommended land pattern when laying out the PCB pads for 1SMC12AT3G. The cathode pad (pin 1) should be the larger, marked side - keep the trace from this pad wide and short to maximize surge current handling. Place the TVS as close as possible to the connector or entry point being protected, ideally within 10 mm, to minimize parasitic inductance that would otherwise add overshoot to the clamping waveform during a fast surge event.
Although the 1SMC12AT3G is rated for 1500 W peak pulse power on a 10/1000 us waveform, single-pulse capability derates linearly to zero at the 150 C maximum junction temperature. In designs where the TVS must absorb repetitive surges (such as on a relay-coil clamp that fires every cycle), verify that the average power dissipation does not exceed what the DO-214AB package can sustain on the available copper pad area. Estimated: with 1 oz copper on a 100 mm^2 cathode pad, sustained dissipation is roughly 1-2 W before additional heatsinking is required.
Do not use the 1SMC12AT3G for circuits that see reverse polarity during installation or fault conditions - this is a unidirectional device, and reverse-biasing it outside its forward rating (~1 V) can cause failure. For polarity-agnostic protection, use a bidirectional equivalent from the same family (such as 1SMC12CAT3G) or pair two unidirectional parts in inverse-parallel across an AC-coupled signal line. Similarly, verify Vrwm exceeds the maximum normal operating rail voltage - using a 12 V TVS on a 13.8 V (typical automotive float) bus leaves no headroom and may cause continuous leakage current.
Series inductance between the TVS and the protected device adds voltage overshoot during a fast (8/20 us) surge pulse beyond what the datasheet Vc figure suggests. Place the TVS immediately adjacent to the IC supply pins being protected; if the line cannot be kept short, add a small decoupling capacitor (1-10 uF) closer to the IC to absorb the inductive spike. This combination of TVS plus bypass cap is the standard protection topology and is shown in the reference design in the Littelfuse 1SMCxxA datasheet.
Compliance-Informationen
Standard 1SMC12AT3G is RoHS/REACH compliant and UL recognized per Littelfuse datasheet. The SZ1SMC12AT3G version is AEC-Q101 qualified for automotive use. Choose SZ variant for AEC-Q100/101 qualification requirements.