Vishay General Semiconductor - Diodes Division SML4742AHE3_A/H

Overview

SML4742AHE3_A/H from Vishay Semiconductors is a surface-mount Zener diode with nominal zener voltage 12 V, ±5 % tolerance (suffix A), 21 mA test current (IZT), 9.1 Ω dynamic impedance (ZZ), and 700 mW power dissipation at TL = 75 °C - used for precision voltage regulation and overvoltage protection in DC power rails of industrial control modules.

For engineers reviewing the SML4742AHE3_A/H datasheet, SML4742AHE3_A/H pinout, SML4742AHE3_A/H application, or SML4742AHE3_A/H equivalent, this device requires verification of reverse breakdown stability under transient surge (380 mApk), thermal derating above 75 °C, and compatibility with SMA (DO-214AC) PCB land patterns per J-STD-020 MSL level 1 handling.

Technical Context

This Zener diode operates in reverse-biased breakdown mode to maintain stable reference voltage across load variations. Its low dynamic impedance (9.1 Ω at 21 mA) ensures minimal output voltage deviation under changing current demand, while the 0.25 μA maximum reverse leakage at VR = 9.1 V supports low-power standby circuits.

The device uses silicon PN junction construction in an epoxy-molded SMA package rated UL 94 V-0, with AEC-Q101 qualification indicated by the "HE3_A/H" suffix - confirming suitability for automotive subsystems requiring enhanced reliability and high-temperature operation up to TJ = 150 °C.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount plastic case with cathode band marking; dimensions 4.93 mm × 3.99 mm × 2.29 mm; weight 64 mg; MSL level 1; peak soldering temperature 260 °C/10 s.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener diode applications.

Compared with BZX84-C12LT1G and 1N4742A, the SML4742AHE3_A/H delivers identical voltage accuracy and comparable impedance but adds AEC-Q101 qualification, MSL level 1 handling, and 700 mW surface-mount power capability - making it optimal for automated production of automotive and industrial SMT assemblies.

Availability

SML4742AHE3_A/H is available at Aetrix Electronics and suitable for industrial power monitoring, automotive sensor reference, consumer overvoltage protection, and medical diagnostic equipment requiring stable component supply with AEC-Q101 assurance and RoHS compliance.

Supply support for SML4742AHE3_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 Semiconductors is a global leader in discrete semiconductors, specializing in high-reliability diodes, MOSFETs, and optoelectronics for demanding industrial and automotive applications.

The SML47xxA series is part of Vishay's surface-mount Zener portfolio designed specifically for stable voltage regulation in space-constrained, high-volume SMT applications where AEC-Q101 compliance and thermal robustness are mandatory.

FAQ

What is the Zener voltage tolerance of SML4742AHE3_A/H?

The SML4742AHE3_A/H has a nominal Zener voltage of 12 V with a tolerance of ±5 %, as confirmed by the "A" suffix in its ordering code and verified in the Electrical Characteristics table (Rev. 2.2, p.3). This tighter tolerance enables more accurate voltage clamping compared to standard ±10 % Zeners, and is critical for applications like automotive sensor reference where drift beyond ±0.6 V may trigger false fault conditions. The SML4742AHE3_A/H achieves this specification at 21 mA test current and 25 °C ambient.

Is SML4742AHE3_A/H qualified for automotive use?

Yes, the SML4742AHE3_A/H is AEC-Q101 qualified, as indicated by the "HE3_A/H" suffix per Vishay's ordering nomenclature and confirmed in the Mechanical Data section (Rev. 2.2, p.1). This qualification covers stress testing for temperature cycling, humidity bias, mechanical shock, and high-temperature operating life - validating its use in automotive body electronics, infotainment power supplies, and ADAS sensor interfaces. The device operates reliably from –65 °C to +150 °C junction temperature.

What is the maximum surge current rating for SML4742AHE3_A/H?

The SML4742AHE3_A/H has a non-repetitive surge current rating of 380 mApk, defined per JEDEC method as an 8.3 ms pulse width square wave superimposed on the 21 mA test current (Rev. 2.2, p.2–3). This value is measured at 25 °C ambient and reflects the device's ability to absorb transient energy without parametric shift or failure. Designers must ensure that external series impedance limits peak current to ≤380 mApk during line surges or ESD events.

Does SML4742AHE3_A/H require moisture sensitivity handling?

No, the SML4742AHE3_A/H is rated MSL level 1 per J-STD-020, meaning it has unlimited floor life and does not require dry-packaging, baking, or special handling prior to reflow soldering (Rev. 2.2, p.1). This simplifies manufacturing logistics for high-volume SMT lines and eliminates risk of popcorning or delamination during reflow. The UL 94 V-0 molding compound further supports process robustness under peak temperatures up to 260 °C for 10 seconds.

What package type does SML4742AHE3_A/H use?

The SML4742AHE3_A/H uses the SMA (DO-214AC) surface-mount package, with standardized dimensions of 4.93 mm × 3.99 mm × 2.29 mm and a cathode band marking (Rev. 2.2, p.5). This package is compatible with standard 12 mm tape-on-reel feeding and supports automated pick-and-place. Its thermal performance is characterized for PCB-mounted copper areas of 8 mm × 8 mm × 2 mm, enabling 700 mW power dissipation at terminal temperature 75 °C.