SMCJ33A-AT - 1500W 33V Uni-Directional TVS | DO-214AB
N.º de pieza: SMCJ33A-AT ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $0.13 | $0,13 |
| 10 | $0.115 | $1,15 |
| 100 | $0.095 | $9,50 |
| 500 | $0.082 | $41,00 |
| 1.000 | $0.073 | $73,00 |
| 3.000 | $0.061 | $183,00 |
SMCJ33A-AT Descripción general
A Transient Voltage Suppressor (TVS) diode is a clamping semiconductor device that diverts destructive transient energy away from sensitive downstream circuitry. When the line voltage exceeds the breakdown threshold, the TVS transitions from a high-impedance state to a low-impedance avalanche mode within picoseconds, shunting surge current to ground and clamping the voltage to a safe level. The DO-214AB (SMC) package family is the 1500 W workhorse of the TVS market, sitting in the hierarchy: TVS diode → ESD/transient protection → discrete semiconductor → circuit protection component.
Key features of the SMCJ33A-AT include a fast response time of typically less than 1 ps from 0 V to VBR(min), glass-passivated junction construction for stable leakage and long-term reliability, a low-profile body for compact board layouts, built-in strain relief for robust surface-mount soldering, and excellent clamping capability per IEC 61000-4-2 (ESD) and IEC 61000-4-4/5 (EFT/surge) guidelines. The repetitive duty cycle is rated at 0.05%, with typical reverse leakage under 1 µA at the working voltage.
The SMCJ33A-AT is widely used for secondary protection of 24 V industrial buses, automotive 12 V/24 V load-dump suppression, telecom -48 V rectifier output rails, and protection of DC/DC converter inputs from inductive kickback. It also appears in USB Type-C PD, RS-485/RS-232 transceiver protection, and surveillance/PoE line-card protection circuits.
When designing with the SMCJ33A-AT, confirm that the system's maximum continuous working voltage never exceeds 33 V, and that the PCB land pattern follows the DO-214AB (SMC) recommendations. Note that for bidirectional requirements (positive and negative transients) the SMCJ33CA variant should be selected instead.
This page consolidates verified distributor pricing (as of 2026-10-05), DO-214AB drop-in alternatives from multiple TVS manufacturers, and design guidance not found in any single manufacturer datasheet — enabling engineers to qualify second sources and reduce BOM risk.
Alternativas directas para SMCJ33A-AT — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con SMCJ33A-AT (mismo factor de forma y huella) — difiere en Halogen-Free, Peak Pulse Current (Ipp), Response Time.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
SMCJ33A-AT/TR7
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
SMCJ33A
✅ Sustitución directa✓ En stock
$0.22 / unidad
Ver hoja de datos →SMCJ33A
✅ Sustitución directa✓ En stock
$0.22 / unidad
Ver hoja de datos →SMCJ33A
✅ Sustitución directa✓ En stock
$0.22 / unidad
Ver hoja de datos →SMCJ33A
✅ Sustitución directa✓ En stock
$0.22 / unidad
Ver hoja de datos →SMCJ33A
✅ Sustitución directa✓ En stock
$0.22 / unidad
Ver hoja de datos →SMCJ33A
✅ Sustitución directa✓ En stock
$0.22 / unidad
Ver hoja de datos →SMCJ33A-13-F
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
SMCJ33A-AT Especificaciones
| Manufacturer | Walsin |
| Series | SMCJ-AT |
| Device Type | TVS Diode (Uni-Directional) |
| Encapsulado | DO-214AB (SMC) |
| Tipo de montaje | Surface Mount |
| Peak Pulse Power (10/1000 µs) | 1500 W |
| Working Peak Reverse Voltage (VRWM) | 33 V |
| Breakdown Voltage (VBR) Min | 36.7 V |
| Clamping Voltage (VC) at Ipp | 53.3 V |
| Peak Pulse Current (Ipp) | 28.2 A |
| Polarity | Uni-Directional |
| Repetition Rate (Duty Cycle) | 0.05% |
| Response Time | < 1 ps (typical, 0 V to VBR min) |
| Temperatura de funcionamiento | -55C to +150C |
| Estado RoHS | Compliant |
| Lead-Free Finish | Yes |
| Sin halógenos | Yes (per 'Green Device' classification) |
Configuración de pines de SMCJ33A-AT
| Pin 1 | Anode — Anode terminal (for uni-directional A-suffix TVS; tie to ground for positive-rail protection) |
| Pin 2 | Cathode — Cathode terminal (cathode bar marked on package top; tie to the protected positive rail) |
Peak Pulse Power vs Pulse Duration (10/1000 µs waveform)
Aplicaciones típicas
SMCJ33A-AT es adecuado para 6 aplicacións: 24V Industrial DC Bus Protection, Automotive 12V Load-Dump Suppression (Auxiliary), Telecom -48V Rectifier Output Protection, USB Type-C PD Port Protection, RS-485/RS-232 Transceiver Protection, Surveillance / PoE Line-Card Protection.
24V Industrial DC Bus Protection
The SMCJ33A-AT protects 24V industrial PLC and factory-automation DC bus lines from voltage transients caused by inductive load switching and lightning-induced surges on long cable runs. With VRWM of 33 V (above the nominal 24 V system rail plus 10% tolerance) and a clamping voltage of 53.3 V at 28.2 A, it safely diverts IEC 61000-4-5 surge pulses away from sensitive PLC inputs and DC/DC converter front ends. The 1500 W peak pulse rating provides ample margin for 8/20 µs surge waveforms up to 1 kV line-to-line. For 24 V PLC systems, place the SMCJ33A-AT directly across the power input terminals with the cathode toward the protected rail.
Recomendado
Automotive 12V Load-Dump Suppression (Auxiliary)
Recomendado
Telecom -48V Rectifier Output Protection
The SMCJ33A-AT clamps transients on telecom -48V rectifier output rails that can experience voltage excursions during hot-swap events, battery discharge transients, and lightning-induced surges on outdoor cabinets. Although the working voltage is positive (33 V), the part is commonly used at the secondary side of -48V systems after the DC/DC isolation stage, where transients are referenced to a local 24 V or 12 V rail. Its 1500 W rating and 53.3 V clamping voltage comfortably protect downstream DC/DC converters and Point-of-Load regulators from surge events.
Recomendado
USB Type-C PD Port Protection
The SMCJ33A-AT protects USB Type-C Power Delivery (PD) port input rails from ESD and surge transients that exceed the USB Type-C specification's 20 V maximum. With VRWM of 33 V and clamping at 53.3 V, it sits above the PD negotiation range (5-20 V) and clamps ESD and surge events per IEC 61000-4-2 (8 kV contact, 15 kV air). The DO-214AB footprint fits standard Type-C connector PCB real estate and adds minimal series inductance for fast transient response. For VBUS lines at 20 V, the SMCJ33A-AT provides clean clamping without interfering with PD handshake signals.
Recomendado
RS-485/RS-232 Transceiver Protection
The SMCJ33A-AT clamps common-mode and differential transients on industrial RS-485 and RS-232 transceiver interfaces, where field wiring can pick up ESD, EFT, and surge events from motor drives and relay contacts. For 24V-rated RS-485 buses (such as those using the SN65HVD75/78/3082E), the SMCJ33A-AT clamps common-mode transients to a safe level while remaining invisible to the data signal under normal conditions. Note: for bidirectional signal-line protection, the SMCJ33CA (bi-directional) variant is recommended over the SMCJ33A-AT.
Recomendado
Surveillance / PoE Line-Card Protection
The SMCJ33A-AT protects Power-over-Ethernet (PoE) line cards and IP surveillance camera interfaces from lightning-induced transients that couple onto outdoor Ethernet cables. With 1500 W peak pulse rating and sub-picosecond response, it clamps 8/20 µs surge waveforms up to several kV per IEEE 802.3 and IEC 61000-4-5. The DO-214AB package is commonly used in conjunction with a gas discharge tube (GDT) and PTC fuse for coordinated two-stage protection. The 33 V working voltage is well above PoE nominal voltages (44-57 V referenced to local ground) — for direct PoE rail clamping, select a higher-VRWM TVS such as 58 V or 60 V.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para SMCJ33A-AT — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | SMCJ33A-AT/TR7 | SMCJ33A | SMCJ33A | SMCJ33A | SMCJ33A |
|---|---|---|---|---|---|---|
| Brand | Walsin | Walsin | Littelfuse | Bourns | Vishay | Diodes Incorporated |
| Package | DO-214AB (SMC) | DO-214AB (SMC) - same | DO-214AB (SMC) - same | DO-214AB (SMC) - same | DO-214AB (SMC) - same | DO-214AB (SMC) - same |
| Peak Pulse Power (10/1000 µs) | 1500 W | 1500 W | 1500 W | 1500 W | 1500 W | 1500 W |
| Working Standoff Voltage (VRWM) | 33 V | 33 V | 33 V | 33 V | 33 V | 33 V |
| Breakdown Voltage (VBR) Min | 36.7 V | 36.7 V | 36.7 V | 36.7 V | 36.7 V | 36.7 V |
| Clamping Voltage (VC) at Ipp | 53.3 V | 53.3 V | 53.3 V | 53.3 V | 53.3 V | 53.3 V |
| Peak Pulse Current (Ipp) | 28.2 A | 28.2 A | 28.2 A | 28.1 A (-0.4%) | 28.2 A | 28.2 A |
| Polarity | Uni-Directional | Uni-Directional | Uni-Directional | Uni-Directional | Uni-Directional | Uni-Directional |
| RoHS / Halogen-Free | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes | Yes / Yes |
Diferenciadores clave
- Cost-competitive 1500 W TVS in JEDEC-standard DO-214AB (frente a Littelfuse SMCJ33A)
- Wide cross-brand second-source availability (frente a SMBJ33A (600 W class))
- Halogen-free and RoHS-compliant Green Device (frente a Older non-RoHS TVS options)
Notas de diseño
Use the recommended DO-214AB (SMC) land pattern per IPC-7351: the cathode pad should be slightly larger than the anode pad to assist heat dissipation during surge events. Minimize trace length between the TVS and the protected IC — keep the connection under 5 mm to reduce parasitic inductance that can cause voltage overshoot above the rated clamping voltage during fast transients. Place the TVS as close as possible to the connector or entry point where transients enter the PCB.
Do not exceed the 33 V working standoff voltage (VRWM) under continuous operation — the part will conduct significant leakage above this threshold. For 24 V industrial systems with +20% tolerance (28.8 V max), the 33 V VRWM provides only 4.2 V margin; consider derating to a 36 V or 40 V TVS if the system experiences sustained overvoltage events. The 1500 W peak pulse rating is for a single 10/1000 µs pulse at 0.05% duty cycle; higher duty cycles limit average power dissipation to ~5 W.
Estimated: at the maximum clamping voltage of 53.3 V and 28.2 A peak pulse current, peak instantaneous power during the surge is approximately 1502 W. The DO-214AB package has a typical thermal resistance (theta_JA) of 50 C/W on a standard JEDEC test board, which permits a single 1500 W pulse without exceeding the 150C maximum junction temperature. For repeated surge events or higher ambient temperatures, calculate junction temperature rise using the surge pulse duration and the transient thermal impedance curve in the manufacturer datasheet.
For high-speed signal-line protection (USB 2.0/3.0, HDMI, Ethernet), the DO-214AB package adds approximately 2-3 pF of capacitance per diode, which can degrade signal integrity at frequencies above 100 MHz. For high-speed interfaces, choose a lower-capacitance TVS array in a smaller package (such as the USBLC6-2SC6 from STMicroelectronics) and reserve the SMCJ33A-AT for power-rail protection where capacitance is not a concern.
Información de cumplimiento
RoHS compliant and halogen-free per Walsin 'Green Device' classification. Not AEC-Q100/AEC-Q101 qualified — for automotive applications, select an automotive-grade TVS from a qualified supplier. REACH compliance not explicitly stated in the provided data; assumed compliant based on industry-standard compliance.