Broadcom Limited ASSR-3210-503E

Overview

ASSR-3210-503E from Broadcom is a single-channel, normally-off, Form A solid-state relay (Photo MOSFET) with optically isolated AlGaAs LED input and dual high-voltage MOSFET output stage. It delivers 250 V output withstand voltage, 0.2 A DC load current, 8 Ω typical on-resistance, and 0.25 ms turn-on time. It replaces electromechanical relays in low-power AC/DC signal switching applications requiring high isolation and fast switching.

For engineers reviewing the ASSR-3210-503E datasheet, pinout, applications, or equivalent options, key selection criteria include its 3750 Vrms input-output isolation, SO-4 surface-mount package, CMOS-compatible 3 mA turn-on threshold, and 0.02 ms turn-off time - all critical for telecom interface protection, medical equipment isolation, and industrial I/O modules.

Technical Context

The ASSR-3210-503E integrates an AlGaAs infrared LED optically coupled to a photovoltaic diode array that drives two discrete high-voltage MOSFETs in series, forming a bidirectional SPST switch. Its output stage operates without external bias, enabling true zero-bias AC/DC switching capability.

It achieves 3750 Vrms isolation per UL1577 via internal plastic insulation with ≥4.9 mm creepage and clearance, and supports operation across –40°C to +85°C ambient. Transient immunity exceeds 1 kV/μs, and input-output capacitance is only 0.4 pF at 1 MHz - essential for noise-sensitive analog and data line isolation.

Key Specifications

Pinout & Package

ASSR-3210-503E uses a 4-pin Small Outline (SO-4) surface-mount package with gull-wing leads, RoHS-compliant and tape-and-reel packaged (1500 units/reel). The package measures 4.40 × 4.30 × 1.20 mm and features 2.54 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar solid-state relay applications.

Compared with TLP3558A and VO3120, the ASSR-3210-503E offers superior speed (0.25 ms vs. ≥0.5 ms), lower R_ON (8 Ω vs. ≥12 Ω), and compact SO-4 packaging - making it optimal for high-density, fast-response industrial and telecom signal switching where 250 V rating is sufficient.

Availability

ASSR-3210-503E is available at Aetrix Electronics and suitable for telecom line interface, industrial PLC I/O, and medical patient monitoring systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for ASSR-3210-503E 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

Broadcom is a global semiconductor leader specializing in optical connectivity, wireless communications, and high-performance analog isolation solutions.

The ASSR-32xx series was designed specifically for reliable, maintenance-free replacement of electromechanical relays in signal-level and low-power load switching - targeting telecom infrastructure, industrial controls, and safety-critical medical isolation.

FAQ

What is the maximum continuous output voltage the ASSR-3210-503E can block?

The ASSR-3210-503E has a rated output withstand voltage of 250 V, meaning it can continuously block up to ±250 V DC or 250 V RMS AC across its output terminals (pins 3 and 4) under specified operating conditions. This value is validated at 25°C with input voltage ≤0.8 V; derating applies above 25°C per Figure 3 in the datasheet. Exceeding this voltage risks output breakdown.

Can the ASSR-3210-503E switch AC loads directly without external components?

Yes, the ASSR-3210-503E supports true bidirectional AC/DC switching without external bias or snubbers due to its symmetric MOSFET output structure. Its 250 V withstand rating and 0.2 A current capacity allow direct connection to 120 V AC or 24 V AC control circuits. However, for inductive loads like solenoids, an external flyback diode or RC snubber is recommended to suppress voltage transients during turn-off.

What is the minimum input current required to reliably turn on the ASSR-3210-503E across temperature?

The ASSR-3210-503E requires a minimum input current of 3 mA to guarantee turn-on across its full operating temperature range (–40°C to +85°C). While the device may activate at lower currents (e.g., ≥0.5 mA at 25°C), Broadcom recommends using ≥5 mA to ensure robust performance over temperature and lifetime. This current level is easily achievable from standard 3.3 V or 5 V CMOS outputs with a series resistor.

Does the ASSR-3210-503E require a heatsink for 0.2 A DC load operation?

No, the ASSR-3210-503E does not require a heatsink for 0.2 A DC operation at ambient temperatures ≤50°C. At 200 mA and 8 Ω R_ON, power dissipation is ~320 mW - within its 400 mW rated output power limit. Derating curves (Figure 1) show maximum allowable current drops to ~0.15 A at 85°C ambient. For sustained 0.2 A operation above 60°C, board-level copper pour or airflow is advised.

How is the 3750 Vrms isolation rating of the ASSR-3210-503E verified and certified?

The 3750 Vrms input-output isolation rating of the ASSR-3210-503E is certified per UL 1577 (component recognition) and CSA Component Acceptance Notice #5. It is measured with pins 1+2 shorted (input) and pins 3+4 shorted (output) for 1 minute at ≤50% relative humidity. This rating reflects dielectric strength across the internal plastic insulation barrier (minimum 0.08 mm thickness), not continuous working voltage - design margins must be applied per end-equipment safety standards.