onsemi SA7V0A

Overview

SA7V0A from Fairchild Semiconductor is a unidirectional 500 W transient voltage suppressor (TVS) diode in DO-15 package, designed for primary overvoltage protection in DC power lines and signal interfaces. It features a 7.0 V reverse stand-off voltage (VRWM), 7.78–8.60 V breakdown voltage (VBR) at 10 mA, 12.0 V clamping voltage (VC) at 41.7 A peak pulse current (IPPM), and operates up to +175 °C junction temperature.

For engineers reviewing the SA7V0A datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, DO-15 terminal mapping, bidirectional variant context (SA7V0CA), clamping performance under 10/1000 μs surge, and real-world ESD/surge protection use cases in industrial power supplies and automotive body electronics.

Technical Context

The SA7V0A employs a glass-passivated silicon junction optimized for fast transient response (<1.0 ps rise time from 0 V to VBR) and low incremental surge resistance. Its unidirectional architecture provides asymmetric conduction-blocking reverse voltage up to 7.0 V while clamping positive surges above VBR with minimal overshoot.

Rated for 500 W peak pulse power on the standardized 10/1000 μs waveform, it delivers 41.7 A IPPM at 12.0 V VC, with <150 μA reverse leakage at VRWM and thermal stability validated across −65 °C to +175 °C operating range.

Key Specifications

Pinout & Package

SA7V0A is housed in a standard DO-15 axial leaded package with cathode indicated by a color band. The device has two terminals: anode and cathode, with unidirectional conduction from anode to cathode.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SA7V0A, SMBJ7.0A offers higher packaging density and faster thermal response but requires PCB redesign, while P6SMB7.0A provides identical electrical performance in SMT format with alternate supply chain validation-neither is pin-compatible due to differing packages, but both serve the same functional role in surge-limited systems.

Availability

SA7V0A is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, and communication interface protection requiring stable component supply and long-life obsolescence management.

Supply support for SA7V0A 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016; its legacy TVS portfolio remains widely deployed in industrial and automotive systems.

The SA7V0A belongs to Fairchild's SAxxxA family of 500 W unidirectional TVS diodes, engineered for robust front-end surge protection in harsh environments where reliability under repetitive transient stress is critical.

FAQ

What is the maximum clamping voltage of the SA7V0A under surge conditions?

The SA7V0A clamps to a maximum of 12.0 V when subjected to its rated peak pulse current of 41.7 A on the 10/1000 μs waveform. This value is guaranteed across temperature and process variation per the Rev. D datasheet and is measured at the device terminals with specified test conditions. The SA7V0A maintains this clamping performance consistently, making it suitable for protecting 5 V logic rails and USB power lines without overstressing downstream regulators or switches.

Is the SA7V0A unidirectional or bidirectional, and how does that affect circuit placement?

The SA7V0A is a unidirectional TVS diode, meaning it conducts only in reverse bias (cathode positive relative to anode) and blocks forward voltage up to ~0.7 V. It must be placed with cathode toward the protected line and anode to ground. Unlike the bidirectional SA7V0CA variant, SA7V0A does not suppress negative transients on the line itself-its function is strictly positive-surge clamping. This makes SA7V0A ideal for DC power rail protection where polarity is fixed.

Can the SA7V0A be used in place of the SA7V0CA for bidirectional protection?

No-the SA7V0A cannot replace the SA7V0CA for bidirectional protection because it lacks symmetrical clamping behavior. The SA7V0CA clamps equally in both directions (±7.0 V VRWM), whereas SA7V0A only clamps positive surges and conducts negative transients as a forward-biased diode (~−0.7 V). Substituting SA7V0A for SA7V0CA would leave the line vulnerable to negative-going transients exceeding −0.7 V, risking damage to connected receivers. Always match device polarity to system surge profile.

What is the thermal derating behavior of the SA7V0A above 75°C ambient?

The SA7V0A's steady-state power dissipation derates linearly from 1.0 W at 75°C ambient to zero at 175°C junction temperature, per Figure 5 in the datasheet. For surge applications, pulse power remains rated at 500 W only at TA = 25°C; above that, Figure 2 shows progressive derating-e.g., at 80°C ambient, usable pulse power drops to ~85% of 500 W. Layout must ensure adequate lead length (0.375") and copper area to maintain TJ ≤ 175°C during repetitive events.

Does the SA7V0A meet any specific international surge immunity standards?

Yes-the SA7V0A's 500 W peak pulse rating on the 10/1000 μs waveform directly supports compliance with IEC 61000-4-5 (surge immunity) Level 4 (4 kV line-to-earth, 2 kV line-to-line) when implemented with appropriate series impedance. Its fast response (<1.0 ps) and low clamping voltage also align with IEC 61000-4-2 (ESD) system-level testing requirements for industrial equipment, though system-level validation remains the responsibility of the end designer.