onsemi SA20ARL

Overview

SA20ARL from onsemi is a unidirectional 500 W peak power MiniMOSORB Zener transient voltage suppressor (TVS) designed for clamping high-energy transients in DC power rails and signal lines. It features a 20 V working peak reverse voltage (VRWM), 32.4 V maximum clamping voltage at 15.4 A peak pulse current, <1 µA leakage at VRWM, and sub-1 ns response time. It is used in industrial power supplies, medical equipment surge protection, and communication interface line protection.

For engineers reviewing the SA20ARL datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to protected circuit's absolute maximum rating, steady-state power dissipation derating above 75°C, UL 497B recognition for isolated loop circuits, and axial lead (Case 59AA) mechanical compatibility with through-hole PCB layouts.

Technical Context

The SA20ARL operates as a voltage-clamping device that remains non-conductive below its 20 V VRWM and rapidly avalanches into low-impedance conduction when transient voltage exceeds its 22.2–24.5 V breakdown range (VBR @ IT = 1 mA). Its clamping action limits downstream voltage to ≤32.4 V during a 1 ms 15.4 A pulse, protecting sensitive ICs from ESD and lightning-induced surges.

It is housed in an axial-leaded Surmetic plastic package (Case 59AA) with cathode band polarity marking, rated for soldering at 260°C for 10 seconds, and qualified per UL 497B for isolated loop circuit protection - a requirement not met by many competing TVS diodes.

Key Specifications

Pinout & Package

SA20ARL is packaged in an axial-leaded Surmetic plastic case (JEDEC DO-41 compatible, Case 59AA), with cathode identified by a colored band. Leads are tin-plated, solderable, and rated for 260°C for 10 seconds at 1/16″ from case.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ20A and P6KE20A, SA20ARL uniquely combines axial through-hole reliability, 500 W surge capability, UL 497B certification, and tight 32.4 V clamping - making it the preferred choice for safety- and surge-critical industrial and medical designs requiring drop-in manufacturability and regulatory acceptance.

Availability

SA20ARL is available at Aetrix Electronics and suitable for industrial power supplies, medical diagnostic equipment, and process control instrumentation requiring stable component supply and long-term lifecycle assurance.

Supply support for SA20ARL 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

onsemi (formerly ON Semiconductor) is a global semiconductor manufacturer specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The SA5.0A Series - including SA20ARL - was engineered specifically for high-reliability transient suppression in safety-critical and regulated environments, with emphasis on UL 497B compliance, axial mechanical robustness, and repeatable clamping performance across temperature and lifetime.

FAQ

What is the clamping voltage of SA20ARL at its rated peak pulse current?

The SA20ARL has a maximum clamping voltage (VC) of 32.4 V at 15.4 A peak pulse current (IPP), measured under the 1 ms exponential waveform defined in Figure 4 of the datasheet. This value ensures protected circuits remain below critical voltage thresholds during standardized surge events such as IEC 61000-4-5. The SA20ARL maintains this clamping performance across its full operating temperature range of −55°C to +175°C.

Does SA20ARL meet UL 497B requirements for isolated loop protection?

Yes, SA20ARL is explicitly listed under UL 497B (File #E116110, Category QVGV2) for protector classification in isolated loop circuits. This certification covers testing for strike voltage breakdown, endurance conditioning, dielectric withstand, and discharge performance - going beyond basic package flammability. The SA20ARL's UL recognition applies directly to its use in 4–20 mA loops and other safety-isolated interfaces, unlike generic TVS diodes lacking this specific listing.

What is the package type and lead configuration of SA20ARL?

SA20ARL uses an axial-leaded Surmetic plastic package designated Case 59AA (JEDEC DO-41 compatible), with a cathode indicated by a colored band. Lead diameter is 0.71–0.86 mm, overall body length is 5.80–7.60 mm, and leads extend ≥25.4 mm. It is Pb-free (RoHS-compliant) and rated for 260°C soldering at 1/16″ from the case for 10 seconds - matching standard through-hole assembly processes.

How does SA20ARL compare to SA20AG in terms of packaging and ordering?

SA20ARL is supplied in tape-and-reel format (5000 units per reel), while SA20AG is packed in 1000-unit boxes. Both share identical electrical specifications and Pb-free Surmetic packaging (Case 59AA), but SA20ARL's tape-and-reel configuration supports automated SMT-compatible through-hole insertion equipment. The "RLG" suffix denotes reel packaging with proper orientation and leader/tail lengths per BRD8011/D specification - essential for high-volume manufacturing of SA20ARL.

What is the maximum steady-state power dissipation for SA20ARL at 75°C lead temperature?

SA20ARL has a steady-state power dissipation (PD) rating of 3.0 W at a lead temperature (TL) of 75°C, with linear derating of 30 mW/°C above that temperature. This reflects its thermal resistance junction-to-lead (RJL) of 33.3°C/W. Unlike peak pulse ratings, this value governs continuous power handling in thermally constrained environments - such as enclosed power supplies - and must be verified using Figure 5's derating curve when TL exceeds 75°C.