Vishay General Semiconductor - Diodes Division SMBJ70CAHM3_A/I

Overview

SMBJ70CAHM3_A/I from Vishay General Semiconductor is a bidirectional surface-mount transient voltage suppressor (TVS) diode in the SMB (DO-214AA) package, designed for robust overvoltage protection of sensitive electronics. It features a 70 V standoff voltage (V_WM), 77.8–86.0 V breakdown voltage (V_BR) at 1 mA, 600 W peak pulse power (10/1000 µs), clamping voltage of 113 V at 5.3 A, and operates across –55 °C to +150 °C junction temperature range - deployed on signal lines of industrial sensor units and telecom interface circuits.

For engineers reviewing the SMBJ70CAHM3_A/I datasheet, SMBJ70CAHM3_A/I pinout, SMBJ70CAHM3_A/I application, or SMBJ70CAHM3_A/I equivalent, this page delivers verified electrical specs, bidirectional clamping behavior, AEC-Q101 qualification status, thermal resistance (R_θJA = 100 °C/W), and halogen-free RoHS-compliant construction per JESD201 Class 2 whisker testing.

Technical Context

This TVS diode uses a glass-passivated silicon junction optimized for fast response (<1 ps) to ESD and lightning-induced transients. Its bidirectional architecture enables symmetrical clamping in both polarities without external polarity management, making it suitable for AC-coupled or floating signal paths such as RS-485, CAN bus physical layers, and Ethernet PHY interfaces.

The device meets MSL Level 1 per J-STD-020 with 260 °C lead-free reflow compatibility and exhibits low incremental surge resistance for stable clamping under repetitive 0.01% duty-cycle surges. Its 100 °C/W junction-to-ambient thermal resistance assumes mounting on 0.2" × 0.2" copper pads - critical for sustained 5.0 W steady-state dissipation at 50 °C ambient.

Key Specifications

Pinout & Package

Package: SMB (DO-214AA), surface-mount, bidirectional configuration with no polarity marking; terminals are matte tin-plated, solderable per J-STD-002 and JESD22-B102.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ70CAHM3_A/I, SMBJ70CAHE3_A/I offers identical protection performance without halogen-free or automotive qualification, while SMAJ70CAHM3_A/I trades 33% lower pulse power for 30% smaller PCB area - enabling trade-offs between ruggedness, compliance, and miniaturization.

Availability

SMBJ70CAHM3_A/I is available at Aetrix Electronics and suitable for industrial sensor interface protection, automotive CAN bus transient suppression, telecom line card surge protection, and consumer USB port ESD hardening requiring stable component supply and long-term lifecycle support.

Supply support for SMBJ70CAHM3_A/I 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, MOSFETs, and protection devices with emphasis on reliability, efficiency, and application-specific optimization.

The SMBJ series is engineered for high-energy transient suppression in harsh environments - targeting automotive, industrial automation, and telecom infrastructure where robustness and AEC-Q101 compliance are mandatory.

FAQ

What is the clamping voltage of SMBJ70CAHM3_A/I at its rated peak pulse current?

The SMBJ70CAHM3_A/I has a maximum clamping voltage (V_C) of 113 V at its rated peak pulse current (I_PPM) of 5.3 A, measured using the standardized 10/1000 µs double-exponential waveform. This value ensures protected circuitry remains below critical overvoltage thresholds during surge events. The SMBJ70CAHM3_A/I maintains this clamping performance across its full operating temperature range from –55 °C to +150 °C.

Is SMBJ70CAHM3_A/I suitable for automotive applications?

Yes, SMBJ70CAHM3_A/I is AEC-Q101 qualified, as indicated by the "HM3" suffix denoting halogen-free, RoHS-compliant, and automotive-grade construction. It is validated for use in automotive subsystems including CAN bus interfaces, body control modules, and infotainment systems where reliability under thermal and electrical stress is critical. The SMBJ70CAHM3_A/I meets stringent automotive qualification requirements including temperature cycling, humidity testing, and mechanical shock.

What does the "CA" suffix mean in SMBJ70CAHM3_A/I?

The "CA" suffix in SMBJ70CAHM3_A/I designates a bidirectional configuration, meaning the device provides symmetrical transient voltage suppression in both polarities - essential for protecting AC-coupled or floating signal lines like RS-485, CAN, or telecom interfaces. Unlike unidirectional variants (e.g., SMBJ70AHM3_A/I), the CA version has no polarity marking and functions identically regardless of voltage polarity applied across its terminals.

How does SMBJ70CAHM3_A/I differ from SMBJ70A variants?

SMBJ70CAHM3_A/I is bidirectional with symmetric clamping, whereas SMBJ70AHM3_A/I is unidirectional and includes a cathode band for polarity identification. The unidirectional version supports forward conduction and specifies I_FSM = 100 A (8.3 ms half-sine), while the CA variant omits this rating. Both share identical V_WM (70 V), V_BR, V_C, P_PPM, and package - but SMBJ70CAHM3_A/I is selected when polarity-agnostic protection is required.

What is the thermal resistance of SMBJ70CAHM3_A/I, and how does it affect layout?

The SMBJ70CAHM3_A/I has a typical junction-to-ambient thermal resistance (R_θJA) of 100 °C/W when mounted on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. This value assumes minimal copper area; increasing pad size or adding thermal vias reduces R_θJA and improves steady-state power handling. For reliable 5.0 W continuous dissipation at 50 °C ambient, the SMBJ70CAHM3_A/I requires adequate PCB copper to maintain T_J ≤ 150 °C.