Vishay General Semiconductor - Diodes Division 1.5SMC20A-M3/57T

Overview

1.5SMC20A-M3/57T from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode designed for robust overvoltage protection in power and signal lines. It features a 20 V breakdown voltage (V_BR = 19.0–21.0 V at 1.0 mA), 17.1 V stand-off voltage (V_WM), clamps to ≤27.7 V at 54.2 A peak pulse current, and delivers 1500 W peak pulse power with a 10/1000 µs waveform - used to safeguard MOSFETs, ICs, and sensor interfaces against lightning-induced transients and inductive switching surges.

For engineers reviewing the 1.5SMC20A-M3/57T datasheet, 1.5SMC20A-M3/57T pinout, 1.5SMC20A-M3/57T application, or 1.5SMC20A-M3/57T equivalent, key selection criteria include its unidirectional polarity, SMC (DO-214AB) package thermal resistance (R_θJA = 75 °C/W), 1.0 µA max reverse leakage at V_WM, and halogen-free RoHS-compliant construction per JESD201 Class 2 whisker test.

Technical Context

This TVS diode operates as a clamping device that remains high-impedance below V_WM (17.1 V) and rapidly avalanches above V_BR (19.0–21.0 V) to limit transient voltages. Its glass-passivated junction ensures stable breakdown behavior and low incremental surge resistance under repetitive 10/1000 µs pulses at 0.01% duty cycle.

Designed for surface-mount assembly on 8.0 mm × 8.0 mm copper pads per terminal, it supports automated placement and meets MSL Level 1 (reflow peak 260 °C). The cathode band denotes polarity, and its junction temperature range spans −65 °C to +150 °C with 6.5 W steady-state power dissipation at 50 °C ambient.

Key Specifications

Pinout & Package

Package: SMC (DO-214AB), surface-mount, unidirectional configuration with cathode band marking. Dimensions: 8.13 mm × 6.22 mm × 2.62 mm (L × W × H); 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 suppression applications.

Compared with SMBJ20A and 1.5KE20A, the 1.5SMC20A-M3/57T uniquely balances 1500 W surge capacity, SMC surface-mount compatibility, and halogen-free compliance - making it optimal for volume-manufactured automotive and industrial systems requiring both robustness and process scalability.

Availability

1.5SMC20A-M3/57T is available at Aetrix Electronics and suitable for automotive ECUs, industrial PLCs, telecom power supplies, and consumer appliance motor controls requiring stable component supply and full traceability.

Supply support for 1.5SMC20A-M3/57T 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, and protection devices with emphasis on reliability, thermal performance, and application-specific qualification.

The 1.5SMC Series was developed to deliver high-power transient suppression in compact SMC packages for automotive, industrial, and telecom applications - prioritizing AEC-Q101 readiness, halogen-free compliance, and repeatable clamping performance under harsh conditions.

FAQ

What is the maximum clamping voltage of the 1.5SMC20A-M3/57T under a 10/1000 µs surge?

The 1.5SMC20A-M3/57T clamps to a maximum of 27.7 V when subjected to its rated peak pulse current of 54.2 A with a 10/1000 µs waveform. This value is measured per Figure 1 in Vishay's 88303 datasheet and reflects worst-case voltage seen by downstream circuitry during standardized surge testing. The 1.5SMC20A-M3/57T maintains this clamping performance across its specified junction temperature range of −65 °C to +150 °C.

Is the 1.5SMC20A-M3/57T suitable for automotive applications?

The 1.5SMC20A-M3/57T itself is commercial-grade (M3 suffix), but the 1.5SMC20A-HM3/57T variant is AEC-Q101 qualified for automotive use. While the 1.5SMC20A-M3/57T shares identical electrical and thermal characteristics, it lacks formal automotive qualification documentation. For production automotive systems, engineers should specify the HM3 suffix version to ensure compliance with stress-test requirements including temperature cycling, humidity bias, and mechanical shock.

How does the SMC package of the 1.5SMC20A-M3/57T compare thermally to SMA or SMB packages?

The SMC (DO-214AB) package of the 1.5SMC20A-M3/57T offers lower thermal resistance than SMA (DO-214AC) or SMB (DO-214AA): R_θJA = 75 °C/W versus ~100–120 °C/W for smaller variants. This allows the 1.5SMC20A-M3/57T to sustain higher average power dissipation in compact layouts. Its larger copper pad area (8.0 mm × 8.0 mm per terminal) directly supports the 1500 W peak pulse rating - a capability not achievable with SMA/SMB footprints.

What is the reverse leakage current specification for the 1.5SMC20A-M3/57T at its stand-off voltage?

At V_WM = 17.1 V and T_A = 25 °C, the 1.5SMC20A-M3/57T exhibits a maximum reverse leakage current (I_D) of 1.0 µA. This low leakage ensures minimal standby power loss and prevents false triggering in high-impedance circuits such as sensor bias networks or precision voltage references. Leakage remains below 5 µA up to 80 % of V_WM across the full operating temperature range.

Can the 1.5SMC20A-M3/57T be used in bidirectional configurations?

No - the 1.5SMC20A-M3/57T is strictly unidirectional, indicated by the "A" suffix and cathode band marking. For bidirectional protection, Vishay specifies the "CA" suffix (e.g., 1.5SMC20CA), which has symmetrical breakdown in both directions and no polarity marking. Using the 1.5SMC20A-M3/57T in reverse-biased AC applications would result in forward conduction and potential failure.