Vishay General Semiconductor - Diodes Division SMCJ45CAHM3_A/H

Overview

SMCJ45CAHM3_A/H from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMC (DO-214AB) package, designed for high-energy surge protection with 45 V standoff voltage, 1500 W peak pulse power rating, and 72.7 V clamping voltage at 20.6 A peak pulse current. It protects sensitive ICs, MOSFETs, and sensor signal lines in automotive, industrial, and telecom systems against inductive switching transients and lightning-induced surges.

For engineers reviewing the SMCJ45CAHM3_A/H datasheet, SMCJ45CAHM3_A/H pinout, SMCJ45CAHM3_A/H application, or SMCJ45CAHM3_A/H equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification, halogen-free RoHS compliance, and compatibility with automated SMT placement on 8.0 mm × 8.0 mm copper pads.

Technical Context

This device operates as a voltage-clamped shunt protector: when reverse voltage exceeds the 50.0–55.3 V breakdown range (at 1 mA test current), it rapidly transitions to low-impedance conduction, limiting transient voltage to ≤72.7 V. Its glass-passivated junction ensures stable performance and fast response time (<1 ns).

Thermal design relies on R_θJA = 75 °C/W (typ.) and R_θJL = 15 °C/W (typ.), requiring PCB copper pad thermal management per JEDEC standards. The HM3 suffix confirms halogen-free, RoHS-compliant construction and AEC-Q101 qualification for automotive-grade reliability.

Key Specifications

Pinout & Package

SMCJ45CAHM3_A/H uses the SMC (DO-214AB) package: a 2-terminal, non-polarized surface-mount case with matte tin-plated leads solderable per J-STD-002 and JESD 22-B102. Bidirectional configuration means no cathode/anode marking; both terminals are functionally symmetric.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transient suppression applications.

Compared with SMCJ45CAHM3_A/H, SMAJ45CAHE3_A/H offers reduced surge robustness in a smaller package, while SMCJ45AHE3_A/H provides identical electrical protection with directional biasing-neither is pin-compatible due to polarity marking and thermal profile differences, making SMCJ45CAHM3_A/H the preferred choice for AEC-Q101-compliant bidirectional protection.

Availability

SMCJ45CAHM3_A/H is available at Aetrix Electronics and suitable for automotive ECUs, industrial PLCs, telecom infrastructure, and consumer power adapters requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for SMCJ45CAHM3_A/H 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

Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in diodes, rectifiers, TVS devices, and optoelectronics with emphasis on reliability, efficiency, and application-specific optimization.

The SMCJ series is engineered for high-power transient suppression in harsh environments, targeting automotive, industrial, and telecom applications where robustness, AEC-Q101 validation, and precise clamping performance are mandatory.

FAQ

What is the clamping voltage of SMCJ45CAHM3_A/H at its rated peak pulse current?

The SMCJ45CAHM3_A/H has a maximum clamping voltage (V_C) of 72.7 V when subjected to its rated peak pulse current of 20.6 A under the standard 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 and defines the upper voltage limit imposed on protected circuitry during surge events. The SMCJ45CAHM3_A/H maintains this clamping performance across its full operating temperature range.

Is SMCJ45CAHM3_A/H suitable for automotive applications?

Yes, SMCJ45CAHM3_A/H is AEC-Q101 qualified and explicitly designated for automotive use via the HM3 suffix, confirming halogen-free, RoHS-compliant construction and validation across temperature cycling, high-temperature reverse bias, and accelerated life testing. It is deployed in engine control units, body electronics, and ADAS sensor interfaces where SMCJ45CAHM3_A/H provides certified surge immunity per ISO 7637-2.

How does the bidirectional configuration of SMCJ45CAHM3_A/H affect its PCB layout?

The bidirectional configuration of SMCJ45CAHM3_A/H eliminates polarity concerns during placement-no cathode band marking is present, and either terminal may connect to line or return. This simplifies layout for AC-coupled or differential paths and avoids orientation errors in automated assembly. However, thermal pad design must still follow Vishay's recommended 8.0 mm × 8.0 mm copper areas per terminal to sustain 1500 W surge dissipation in SMCJ45CAHM3_A/H.

What is the standoff voltage rating for SMCJ45CAHM3_A/H, and how does it relate to system operating voltage?

The standoff voltage (V_WM) of SMCJ45CAHM3_A/H is 45 V, meaning it remains in high-impedance state up to this DC or RMS voltage level. For reliable operation, V_WM must exceed the system's maximum normal operating voltage-including tolerances and ripple-by ≥10 %. In a 36 V nominal automotive system, SMCJ45CAHM3_A/H provides appropriate margin; exceeding 45 V risks premature conduction and power loss in SMCJ45CAHM3_A/H.

Does SMCJ45CAHM3_A/H require a heatsink for standard operation?

No external heatsink is required for SMCJ45CAHM3_A/H under normal operating conditions, as its thermal design relies on PCB copper pads (minimum 8.0 mm × 8.0 mm per terminal) to dissipate power. With R_θJA = 75 °C/W (typ.), the device safely handles its 6.5 W steady-state power dissipation (P_D) at T_A = 50 °C when mounted per JEDEC guidelines. Heatsinking is unnecessary unless ambient exceeds 85 °C or surge duty cycle is unusually high in SMCJ45CAHM3_A/H.