Vishay General Semiconductor - Diodes Division SMAJ188A-M3/61

Overview

SMAJ188A-M3/61 from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients up to 328 V at 0.91 A peak pulse current, with 188 V stand-off voltage and 400 W peak pulse power (10/1000 μs), protecting MOSFETs, ICs, and sensor signal lines in industrial and automotive power rails.

For engineers reviewing the SMAJ188A-M3/61 datasheet, SMAJ188A-M3/61 pinout, SMAJ188A-M3/61 application, or SMAJ188A-M3/61 equivalent, key selection criteria include clamping voltage (VC = 328 V), breakdown voltage range (209–231 V), low leakage (<1.0 μA at 188 V), thermal resistance (RθJA = 120 °C/W), and halogen-free RoHS-compliant M3 suffix construction.

Technical Context

This TVS diode operates as a unidirectional avalanche clamp, triggered when reverse voltage exceeds its breakdown threshold (VBR min = 209 V, max = 231 V). It responds in <1 ps to transient overvoltages and maintains stable clamping under repetitive 0.01% duty cycle surges.

Designed for placement on PCB copper pads (0.2" × 0.2"), it delivers 400 W peak pulse power below 78 V and derates to 300 W above 78 V per Fig. 2. Its glass-passivated junction ensures robust surge handling, while M3 suffix confirms halogen-free, RoHS-compliant commercial-grade construction meeting JESD 201 Class 2 whisker resistance.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002 and JESD 22-B102. Cathode indicated by band; anode is unmarked end.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ188A-E3/61, the M3 suffix adds halogen-free assurance for automotive Tier 1 compliance; versus SMAJ170A-M3/61, SMAJ188A-M3/61 trades 18 V higher stand-off for 53 V higher clamping, favoring systems with wider voltage margins over tighter transient control.

Availability

SMAJ188A-M3/61 is available at Aetrix Electronics and suitable for industrial motor drives, automotive body control modules, telecom power supplies, and consumer appliance mainboard rails requiring stable component supply and halogen-free compliance.

Supply support for SMAJ188A-M3/61 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, power efficiency, and AEC-Q qualification.

The SMAJ series targets board-level transient suppression in harsh environments, with design focus on high-power clamping, low leakage, and robust thermal performance in compact surface-mount packages.

FAQ

What is the clamping voltage of SMAJ188A-M3/61 at its rated peak pulse current?

The SMAJ188A-M3/61 has a maximum clamping voltage (VC) of 328 V at its specified peak pulse current (IPPM) of 0.91 A under the 10/1000 μs waveform condition. This value is measured per Fig. 1 and Table on page 2 of Vishay document 88390, and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ188A-M3/61 maintains this clamping performance across its full operating temperature range when mounted per recommended pad layout.

Is SMAJ188A-M3/61 suitable for automotive applications?

SMAJ188A-M3/61 is halogen-free and RoHS-compliant but not AEC-Q101 qualified - its base ordering code uses "M3", not "HM3_X". For automotive use, Vishay specifies HM3-suffixed variants (e.g., SMAJ188AHM3_A/H) with explicit AEC-Q101 qualification. The SMAJ188A-M3/61 is approved for industrial and commercial applications; engineers must select HM3_X versions for automotive-grade deployment. Always verify qualification status via Vishay's official part search before automotive design-in.

What is the thermal resistance and how does it affect PCB layout for SMAJ188A-M3/61?

The SMAJ188A-M3/61 has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W, measured on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. To achieve rated 400 W pulse power, PCB layout must provide at least this pad area - reducing copper area increases junction temperature and risks thermal runaway during repetitive surges. The SMAJ188A-M3/61 also has RθJL = 30 °C/W, confirming efficient heat transfer to PCB traces when properly soldered.

How does the M3 suffix differ from E3 in SMAJ188A-M3/61?

The M3 suffix in SMAJ188A-M3/61 denotes halogen-free, RoHS-compliant construction, whereas E3 indicates RoHS-compliant but not halogen-free. Both meet JESD 201 Class 2 whisker resistance and J-STD-020 MSL Level 1, but only M3 satisfies strict halogen restrictions (e.g., IEC 61249-2-21) required by many automotive and green-electronics programs. Electrically and mechanically, SMAJ188A-M3/61 and SMAJ188A-E3/61 are identical - the distinction is purely material-content compliance.

Can SMAJ188A-M3/61 be used in bidirectional configurations?

No - SMAJ188A-M3/61 is a unidirectional TVS diode, identified by the "A" suffix (vs. "CA" for bidirectional). Its cathode band marks polarity, and it conducts only in reverse bias above VBR. For bidirectional protection at 188 V, the correct part is SMAJ188CA-M3/61, which exhibits symmetrical clamping in both directions. Using SMAJ188A-M3/61 in bidirectional circuits may result in forward conduction damage or inadequate protection during positive transients.