Vishay General Semiconductor - Diodes Division SMAJ60CAHM3_A/H

Overview

SMAJ60CAHM3_A/H from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for robust overvoltage protection of sensitive electronics. It features a 60 V standoff voltage (V_WM), 66.7–73.7 V breakdown voltage (V_BR) at 1 mA, 96.8 V maximum clamping voltage (V_C) at 4.1 A peak pulse current, and 400 W peak pulse power (10/1000 μs waveform), commonly deployed on power rails and signal lines in automotive ECUs and industrial sensor interfaces.

For engineers reviewing the SMAJ60CAHM3_A/H datasheet, SMAJ60CAHM3_A/H pinout, SMAJ60CAHM3_A/H application, or SMAJ60CAHM3_A/H equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification, halogen-free RoHS compliance, and compatibility with automated SMT assembly on 0.2" × 0.2" copper pads.

Technical Context

This TVS diode operates symmetrically in both directions due to its bidirectional construction, enabling suppression of positive and negative transients without polarity sensitivity. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1.0 μA at V_WM), while the low incremental surge resistance supports rapid energy dissipation during ESD or lightning-induced surges.

The device is rated for continuous power dissipation of 3.3 W at 50 °C on an infinite heatsink, with thermal resistance of 120 °C/W (junction-to-ambient) and 30 °C/W (junction-to-lead). It meets MSL Level 1 per J-STD-020 and is qualified to AEC-Q101 for automotive underhood applications requiring reliable operation from –55 °C to +150 °C.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, bidirectional configuration with no polarity marking. Cathode/anode terminals are symmetrical; device functions identically regardless of orientation across protected line.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ60CAHE3_A/H, the SMAJ60CAHM3_A/H adds halogen-free compliance without sacrificing AEC-Q101 qualification or clamping performance; versus SMBJ60CAHM3_A/H, it trades peak power headroom for smaller SMA footprint-critical for dense automotive ADAS module layouts.

Availability

SMAJ60CAHM3_A/H is available at Aetrix Electronics and suitable for automotive electronic control units, industrial sensor signal conditioning circuits, and telecom interface protection requiring stable component supply across multi-year production cycles.

Supply support for SMAJ60CAHM3_A/H 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 high-reliability diodes, MOSFETs, optoelectronics, and passive components for automotive, industrial, and computing markets.

The SMAJ series is engineered specifically for board-level transient suppression in harsh environments, emphasizing AEC-Q101 qualification, repeatable clamping, and SMT manufacturability in compact surface-mount packages.

FAQ

What does the "CA" suffix indicate in SMAJ60CAHM3_A/H?

The "CA" suffix denotes a bidirectional configuration, meaning SMAJ60CAHM3_A/H provides symmetrical transient suppression for both positive and negative voltage excursions. Unlike unidirectional "A" variants, it has no cathode marking and functions identically regardless of PCB orientation-ideal for AC-coupled or differential signal lines where polarity is undefined.

Is SMAJ60CAHM3_A/H suitable for protecting CAN FD bus lines?

Yes, SMAJ60CAHM3_A/H is appropriate for CAN FD physical layer protection: its 60 V V_WM exceeds typical CAN common-mode range (±40 V), 96.8 V V_C stays below most CAN transceiver absolute maximum ratings (120 V), and its low capacitance (~100 pF) avoids signal integrity degradation at 5 Mbps. It must be placed close to the connector with short traces to maintain effectiveness.

How does the HM3 suffix differ from E3 or HE3 in SMAJ60CAHM3_A/H?

The "HM3" suffix in SMAJ60CAHM3_A/H specifies halogen-free, RoHS-compliant construction with AEC-Q101 qualification. In contrast, "E3" is RoHS-compliant but not halogen-free, and "HE3" is RoHS-compliant and AEC-Q101 qualified but also not halogen-free. HM3 meets strict environmental mandates like JESD201 Class 2 whisker resistance and UL 94 V-0 flammability without brominated compounds.

What is the maximum allowable PCB pad size for optimal thermal performance of SMAJ60CAHM3_A/H?

For rated 400 W peak pulse power, SMAJ60CAHM3_A/H requires minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal, as specified in the Vishay datasheet. Larger pads improve heat spreading and sustain repetitive surge duty cycles; reducing pad area below this de-rates PPPM and increases junction temperature rise during transient events.

Does SMAJ60CAHM3_A/H require derating above 25 °C ambient temperature?

Yes, SMAJ60CAHM3_A/H must be derated above 25 °C ambient: its peak pulse power decreases linearly per Figure 2 in the datasheet, reaching 300 W at 78 V and above. At 85 °C ambient, the usable PPPM drops to ~320 W for 60 V devices; full 400 W capability is only guaranteed at T_A ≤ 25 °C with proper PCB copper thermal mass.