Vishay General Semiconductor - Diodes Division SMA6J20AHM3/5A

Overview

SMA6J20AHM3/5A from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMA (DO-214AC) package, with 20 V stand-off voltage (V_WM), 22.2–24.5 V breakdown voltage (V_BR at I_T = 1 mA), and 31.4 V maximum clamping voltage (V_C) at 19.1 A peak pulse current (I_PP, 10/1000 µs). It delivers 600 W peak pulse power (10/1000 µs) and is rated for 50 A non-repetitive surge current (I_FSM), used to protect MOSFETs, ICs, and sensor signal lines against inductive switching transients in industrial and telecom equipment.

For engineers reviewing the SMA6J20AHM3/5A datasheet, SMA6J20AHM3/5A pinout, SMA6J20AHM3/5A application, or SMA6J20AHM3/5A equivalent, key selection criteria include verified clamping performance at 19.1 A, unidirectional polarity confirmation, thermal resistance (R_θJA = 120 °C/W), MSL Level 1 compliance, and halogen-free RoHS-compliant construction per suffix M3/5A.

Technical Context

This TVS diode operates as a voltage-clamped shunt protector: under normal bias it presents <0.2 µA leakage at 20 V (V_WM), then avalanches sharply above 22.2 V (min V_BR) to clamp transients. Its dynamic resistance (R_D = 0.361 Ω) ensures predictable V_C rise with increasing I_PP, per V_C = R_D × I_PP + V_BR(max).

Designed for PCB-level transient suppression, it uses a planar junction structure in an SMA package with matte tin-plated leads solderable per J-STD-002, rated for T_J = –55 to +150 °C, and derated linearly above 25 °C per Fig. 2 in the datasheet.

Key Specifications

Pinout & Package

SMA6J20AHM3/5A is housed in the SMA (DO-214AC) surface-mount package: 4.93 mm × 3.99 mm × 2.20 mm body with 2.54 mm lead pitch, matte tin-plated terminals, and cathode indicated by a color band. Mounting requires minimum 5.0 mm × 5.0 mm copper pads per terminal per datasheet note (2).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMA6J20AHM3/5A, SMA6J20AHE3/5A offers identical protection performance with standard RoHS compliance, while SMCJ20A-M3/57T provides 2.5× higher pulse power in a larger package-enabling robustness upgrades without redesigning clamping thresholds.

Availability

SMA6J20AHM3/5A is available at Aetrix Electronics and suitable for industrial motor control, telecom power interface, and automotive body electronics requiring stable component supply, consistent halogen-free compliance, and MSL Level 1 manufacturability.

Supply support for SMA6J20AHM3/5A 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 and application-specific optimization.

The SMA6J series is part of Vishay's Transient Voltage Suppressor portfolio, engineered for cost-effective, high-volume PCB-level protection against inductive switching and lightning surges in consumer, industrial, and telecom systems.

FAQ

What is the clamping voltage of SMA6J20AHM3/5A at its rated peak pulse current?

The SMA6J20AHM3/5A has a maximum clamping voltage (V_C) of 31.4 V when subjected to a 10/1000 µs waveform at 19.1 A peak pulse current (I_PP). This value is measured per standard test conditions in the Vishay datasheet (Document Number: 89460), and defines the upper voltage limit imposed on protected circuits during surge events. The SMA6J20AHM3/5A maintains this clamping performance across its specified operating temperature range.

Does SMA6J20AHM3/5A support automated SMT placement?

Yes, SMA6J20AHM3/5A supports automated surface-mount placement due to its standardized SMA (DO-214AC) package geometry, matte tin-plated leads compliant with J-STD-002, and MSL Level 1 rating allowing exposure to floor life without baking. The 7500-unit 13-inch tape-and-reel format (suffix /5A) is optimized for high-speed pick-and-place machines, and the low-profile design minimizes tombstoning risk during reflow.

Is SMA6J20AHM3/5A unidirectional or bidirectional?

SMA6J20AHM3/5A is unidirectional, as confirmed in the Vishay datasheet "Features" section and electrical characteristics table. It conducts only during reverse-bias overvoltage events, with forward voltage drop (V_F) of 3.5 V at 25 A (pulse test). The cathode band marking on the SMA package visually indicates polarity, and it must be oriented with cathode toward the line being protected.

What is the thermal resistance of SMA6J20AHM3/5A, and how does it affect layout?

The SMA6J20AHM3/5A has a typical junction-to-ambient thermal resistance (R_θJA) of 120 °C/W when mounted on 5.0 mm × 5.0 mm copper pads per terminal, as specified in the Vishay thermal characteristics table. This value directly impacts power derating: at 50 °C ambient, its power dissipation drops to 4 W. Layout must replicate the recommended pad size and copper area to achieve rated surge capability and avoid thermal runaway during repetitive transients.

How does the M3 suffix in SMA6J20AHM3/5A differ from E3?

The M3 suffix in SMA6J20AHM3/5A denotes halogen-free, RoHS-compliant construction meeting JEDEC JESD201 Class 2 whisker resistance, whereas E3 indicates standard RoHS compliance without halogen-free assurance. Both share identical electrical parameters, package, and MSL rating. The SMA6J20AHM3/5A is intended for applications requiring full material compliance documentation, such as automotive or green-certified industrial products, where brominated flame retardants are prohibited.