onsemi SA110A

Overview

SA110A from Fairchild Semiconductor is a unidirectional 500 W transient voltage suppressor (TVS) diode in DO-15 package, with 110 V reverse stand-off voltage (VRWM), 122–135 V breakdown voltage (VBR), 177 V clamping voltage at peak pulse current, and <1.0 μA reverse leakage above 10 V. It protects power rails and I/O lines in industrial motor drives against ESD and lightning-induced surges.

For engineers reviewing the SA110A datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to system rail, peak pulse current capability under 10/1000 μs waveform, junction temperature rating up to +175°C, and DO-15 mechanical compatibility with legacy PCB footprints.

Technical Context

The SA110A operates as a unidirectional avalanche diode, activated when reverse voltage exceeds its specified breakdown range (122–135 V). Its glass-passivated junction ensures stable VBR tolerance and low incremental surge resistance during transient events.

It responds in less than 1.0 ps from 0 V to breakdown, delivering precise overvoltage clamping for DC power inputs and analog sensor interfaces. The device sustains 500 W peak pulse power on standard 10/1000 μs waveform and handles non-repetitive forward surge currents up to 70 A per JEDEC method.

Key Specifications

Pinout & Package

SA110A is housed in a DO-15 axial-leaded package with cathode indicated by a color band. Leads are 0.375" long; thermal derating applies above 75°C ambient.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ110A and P6SMB110A, SA110A offers through-hole DO-15 compatibility for serviceable industrial hardware, lower leakage for precision sensing, and proven thermal performance in leaded configurations-making it optimal for field-replaceable modules and high-temperature chassis-mounted installations.

Availability

SA110A is available at Aetrix Electronics and suitable for industrial motor drives, telecom power supplies, energy metering systems, and isolated analog front-ends requiring stable component supply and long-lifecycle support.

Supply support for SA110A 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.

The SAxxxA series was designed for cost-effective, high-reliability transient suppression in industrial and infrastructure equipment where DO-15 form factor, 500 W surge rating, and 175°C junction operation are essential.

FAQ

What is the clamping voltage of the SA110A under full-rated surge conditions?

The SA110A clamps to a maximum of 177 V when subjected to its rated peak pulse current on a 10/1000 μs waveform. This value is measured at the specified IPPM of 2.8 A and ensures downstream circuitry remains within safe voltage limits during standardized surge events. The SA110A maintains this clamping performance across its full operating temperature range up to +175°C junction temperature.

Is the SA110A unidirectional or bidirectional, and how is polarity identified?

The SA110A is a unidirectional transient voltage suppressor. Polarity is identified by a color band on the cathode end of the DO-15 package - the banded end connects to the protected line, while the unbanded anode connects to ground or return. Bidirectional variants in the same family use the "C" suffix (e.g., SA110CA) and lack the color band.

What is the maximum continuous reverse voltage the SA110A can withstand without clamping?

SA110A has a reverse stand-off voltage (VRWM) of 110 V, meaning it remains in high-impedance blocking mode up to this DC or RMS voltage level. Operation at or slightly above 110 V is permissible only if transient margins and thermal limits are verified; sustained voltage beyond VRWM risks premature conduction and accelerated degradation. The SA110A's specified breakdown starts at 122 V, providing a defined guardband.

Does the SA110A meet any international surge immunity standards out-of-the-box?

The SA110A's 500 W peak pulse power rating on the 10/1000 μs waveform aligns with the energy requirements of IEC 61000-4-5 Level 4 (4 kV line-to-earth, 2 kV line-to-line) when used with appropriate series impedance. While the SA110A itself is a component-not a certified system-the device is routinely deployed in designs achieving full compliance when integrated per application notes such as Fairchild AN-9402. System-level validation remains the designer's responsibility.

How does the SA110A's leakage current compare to similar TVS diodes at its VRWM?

At its 110 V reverse stand-off voltage, the SA110A exhibits less than 1.0 μA of reverse leakage current - significantly lower than many competing 110 V TVS devices, which commonly specify 5–10 μA. This ultra-low leakage preserves accuracy in high-impedance voltage sensing circuits and reduces standby power loss in always-on industrial controllers. The SA110A achieves this while maintaining full 500 W surge capability and 175°C junction rating.