Vishay General Semiconductor - Diodes Division P4SMA540AHM3_A/H

Overview

P4SMA540AHM3_A/H from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMA (DO-214AC) package, rated for 540 V breakdown voltage (V_BR = 513–567 V at I_T = 1.0 mA), 400 W peak pulse power (10/1000 µs), 0.41 A maximum clamping current (I_PPM), and 740 V maximum clamping voltage (V_C) - designed to protect high-voltage DC power rails and industrial sensor interfaces against ESD and inductive switching transients.

For engineers reviewing the P4SMA540AHM3_A/H datasheet, P4SMA540AHM3_A/H pinout, P4SMA540AHM3_A/H application, or P4SMA540AHM3_A/H equivalent, this device serves as an AEC-Q101 qualified, halogen-free, RoHS-compliant TVS for automotive-grade 400 V+ systems requiring stable clamping performance, low leakage (<1.0 µA at V_WM = 459 V), and MSL Level 1 reflow compatibility up to 260 °C.

Technical Context

The P4SMA540AHM3_A/H operates as a unidirectional avalanche diode with glass-passivated junction, delivering precise voltage clamping during transient events. Its 740 V clamping voltage at 0.41 A ensures robust overvoltage protection for 48 V–400 V DC systems while maintaining <1.0 µA reverse leakage at 459 V stand-off voltage.

Thermally, it features R_θJA = 120 °C/W and R_θJL = 30 °C/W, enabling reliable operation up to T_J = +150 °C. The device is qualified to AEC-Q101 and meets J-STD-020 MSL Level 1, supporting automated SMT placement on standard PCB copper pads (0.2" × 0.2").

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, low-profile plastic case with matte tin-plated leads; polarity indicated by cathode band on unidirectional devices.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ540A and SMCJ540A, the P4SMA540AHM3_A/H offers the smallest footprint (SMA) and AEC-Q101/halogen-free compliance out-of-box, making it optimal for space-constrained, automotive-qualified secondary protection where 400 W clamping suffices.

Availability

P4SMA540AHM3_A/H is available at Aetrix Electronics and suitable for automotive power rail protection, industrial HV sensor interface, telecom DC feeder protection, and renewable energy inverter control requiring stable component supply across production lifecycles.

Supply support for P4SMA540AHM3_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 diodes, rectifiers, TVS, and optoelectronics with emphasis on reliability, automotive qualification, and high-volume manufacturability.

The P4SMA Series targets cost-sensitive, high-reliability transient suppression in automotive, industrial, and telecom applications - engineered for automated assembly, AEC-Q101 compliance, and consistent clamping performance across temperature and life.

FAQ

What is the maximum clamping voltage of the P4SMA540AHM3_A/H under standard test conditions?

The P4SMA540AHM3_A/H has a maximum clamping voltage (V_C) of 740 V when subjected to a 10/1000 µs surge waveform at its rated peak pulse current of 0.41 A. This value is measured per JEDEC standards and reflects the highest voltage the protected circuit will experience during a defined transient event. The P4SMA540AHM3_A/H maintains this clamping performance across its full operating temperature range (-65 °C to +150 °C).

Is the P4SMA540AHM3_A/H qualified for automotive applications?

Yes, the P4SMA540AHM3_A/H is AEC-Q101 qualified, as confirmed by Vishay's ordering code suffix "HM3" (halogen-free, RoHS-compliant, AEC-Q101 qualified) and revision-specific documentation. It is intended for use in automotive subsystems such as body control modules, battery management systems, and ADAS sensor power supplies where transient immunity and long-term reliability are critical. The P4SMA540AHM3_A/H undergoes stress testing per AEC-Q101 requirements including HTRB, HTGB, and temperature cycling.

What does the "_A/H" suffix in P4SMA540AHM3_A/H indicate?

The "_A/H" suffix in P4SMA540AHM3_A/H denotes the revision level ("A") and packaging format ("H" = 7-inch diameter plastic tape and reel, 1800 units per reel). This matches Vishay's official ordering information table, where "H" specifies the reel size and quantity, and "A" identifies the first revision of the HM3 variant for the P4SMA540A family. The P4SMA540AHM3_A/H is not a functional variant - electrical specs align fully with the base P4SMA540A device.

Can the P4SMA540AHM3_A/H be used in bidirectional configurations?

No, the P4SMA540AHM3_A/H is a unidirectional TVS diode, as indicated by its "A" suffix (not "CA") and absence of bidirectional V_BR/V_WM ratings in its datasheet row. Bidirectional variants use "CA" suffixes (e.g., P4SMA540CA) and exhibit symmetric clamping in both polarities. Using the P4SMA540AHM3_A/H in reverse-biased mode beyond its 459 V stand-off voltage will cause avalanche conduction only at the cathode-anode junction - it lacks symmetrical breakdown behavior required for true bidirectional protection.

What is the thermal resistance of the P4SMA540AHM3_A/H, and how does it affect layout design?

The P4SMA540AHM3_A/H has a typical junction-to-ambient thermal resistance (R_θJA) of 120 °C/W and junction-to-lead resistance (R_θJL) of 30 °C/W, measured on minimum recommended copper pads (0.2" × 0.2"). To maintain T_J ≤ 150 °C under 3.3 W steady-state dissipation, PCB layout must provide adequate copper area and minimize trace length to thermal vias. The P4SMA540AHM3_A/H is not intended for continuous power dissipation; its thermal design focuses on transient energy absorption, not DC thermal management.