Vishay General Semiconductor - Diodes Division SMBG70CA-M3/5B

Overview

SMBG70CA-M3/5B from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMBG (DO-215AA) package, designed for robust overvoltage protection of signal and power lines. It features a 70 V stand-off 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 AEC-Q101 qualification for automotive use.

For engineers reviewing the SMBG70CA-M3/5B datasheet, SMBG70CA-M3/5B pinout, SMBG70CA-M3/5B application, or SMBG70CA-M3/5B equivalent, key selection criteria include bidirectional clamping behavior, low clamping ratio (VC/VWM ≈ 1.61), MSL Level 1 moisture sensitivity, halogen-free RoHS compliance (M3 suffix), and suitability for 12 V/24 V automotive power rail and sensor line protection.

Technical Context

This device operates as a voltage-clamped shunt protector: under normal conditions it presents high impedance (>1 μA leakage at 70 V), then rapidly avalanches to limit transient voltages when exceeding V_BR. Its bidirectional symmetry enables protection against both positive and negative polarity surges without polarity constraints.

Engineered for automotive-grade reliability, SMBG70CA-M3/5B delivers 100 A non-repetitive surge current capability (IFSM), junction temperature range of –55 °C to +150 °C, and thermal resistance R_θJA = 100 °C/W on standard 5.0 mm × 5.0 mm copper pads - enabling stable operation in under-hood environments with minimal heatsinking.

Key Specifications

Pinout & Package

Package: SMBG (DO-215AA) - surface-mount, low-profile (max height 1.96 mm), matte tin-plated leads, UL 94 V-0 molding compound, compatible with reflow soldering (peak 260 °C, MSL Level 1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ70CA-T3 and 1.5KE70CA, SMBG70CA-M3/5B uniquely combines AEC-Q101 qualification, SMBG's compact footprint (30% smaller than SMB), and optimized thermal performance (R_θJA = 100 °C/W) - making it the preferred choice for automated, high-reliability automotive and industrial SMT production.

Availability

SMBG70CA-M3/5B is available at Aetrix Electronics and suitable for automotive ECU design, CAN bus interface development, industrial sensor module production, and telecom line card manufacturing requiring stable component supply and long-term lifecycle support.

Supply support for SMBG70CA-M3/5B 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 SMBG series was engineered specifically for high-density, automotive-grade transient suppression - delivering AEC-Q101 validated performance in the smallest possible surface-mount package for modern electronic control units and sensor systems.

FAQ

What does the "CA" suffix indicate in SMBG70CA-M3/5B?

The "CA" suffix denotes a bidirectional configuration: SMBG70CA-M3/5B contains two back-to-back avalanche diodes in a single SMBG package, enabling symmetrical clamping for both positive and negative transients. This eliminates the need for polarity-aware placement and supports AC-coupled or floating signal lines such as CAN, LIN, or differential sensor outputs - unlike unidirectional variants (e.g., SMBG70A-M3/5B) which require correct cathode orientation.

Is SMBG70CA-M3/5B suitable for protecting a 24 V automotive system?

Yes, SMBG70CA-M3/5B is appropriate for 24 V nominal systems: its 70 V stand-off voltage (V_WM) provides ≥1.9× margin above maximum steady-state rail voltage (including regulation tolerance and ripple), while its 113 V clamping voltage remains within safe limits for 36 V-rated downstream components. It meets ISO 7637-2 Pulse 5a requirements and is AEC-Q101 qualified - confirming suitability for under-hood 24 V applications like commercial vehicle ECUs and battery management systems.

How does the "M3" suffix affect SMBG70CA-M3/5B compliance and processing?

The "M3" suffix indicates halogen-free, RoHS-compliant construction with matte tin-plated leads that meet J-STD-002 and JESD 22-B102 solderability standards. It also satisfies JESD 201 Class 2 whisker resistance. Unlike "E3" variants, M3 ensures full compliance with stringent environmental regulations (e.g., EU RoHS Annex II, China RoHS) and supports lead-free reflow profiles up to 260 °C peak - critical for high-reliability automotive and industrial manufacturing.

What is the maximum allowable printed circuit board pad size for SMBG70CA-M3/5B to achieve rated 600 W pulse power?

To achieve the full 600 W peak pulse power rating, SMBG70CA-M3/5B must be mounted on minimum recommended copper pads: 0.2" × 0.2" (5.0 mm × 5.0 mm) per terminal, as specified in the Vishay datasheet (Fig. 2 and notes). Smaller pads increase thermal resistance, causing junction temperature rise and derating of pulse power - e.g., at 75 °C ambient, power must be reduced by ~25% versus the 25 °C test condition. Thermal simulation or empirical testing is advised for non-standard layouts.

Can SMBG70CA-M3/5B replace SMBJ70CA in an existing design?

SMBG70CA-M3/5B is not a direct drop-in replacement for SMBJ70CA due to package differences: SMBG (DO-215AA) has a 3.94 mm × 2.10 mm body vs. SMB (DO-214AA) at 4.57 mm × 2.84 mm, with distinct pad layouts and thermal characteristics. While both share identical electrical specs (V_WM, V_BR, P_PPM, V_C), the SMBG variant offers lower R_θJA (100 vs. 120 °C/W) and AEC-Q101 qualification. Layout revision is required; verify mechanical fit and thermal performance in the target application before substitution.