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Broadcom Limited ASSR-1218-503E
- Part No.:
- ASSR-1218-503E
- Manufacturer:
- Broadcom Limited
- Category:
- Solid State Relays (SSR)
- Package:
- 4-SOP (0.173", 4.40mm)
- Datasheet:
-
ASSR-1218-503E.pdf
- Description:
- SSR RELAY SPST-NO 200MA 0-60V
- Quantity:
- Payment:
- Shipping:
Inventory:17,766
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Product details
Overview
The ASSR-1218-503E from Broadcom is a single-channel, normally-off, solid-state relay (Photo MOSFET) in a 4-pin SO surface-mount package. It features 60 V output withstand voltage, 0.2 A DC output current rating, 10 Ω maximum on-resistance, and 3750 Vrms input-output isolation. It replaces electromechanical relays in low-power signal switching applications such as telecom line interface boards and industrial PLC I/O modules.
For engineers reviewing the ASSR-1218-503E datasheet, pinout, applications, or equivalent options, key selection criteria include its 3 mA minimum turn-on LED current, 0.8 V maximum turn-off threshold, gull-wing SO-4 footprint compatibility, and UL1577/CSA-certified insulation for safety-critical isolation.
Technical Context
The ASSR-1218-503E integrates an AlGaAs infrared LED optically coupled to a high-speed photovoltaic diode array and driver circuit that controls a single discrete high-voltage MOSFET. Its output stage operates as a bidirectional SPST switch with no polarity dependence, supporting both AC and DC loads up to 60 V.
It delivers galvanic isolation via internal optical coupling, achieving 3750 Vrms withstand voltage per UL1577 and 1012 Ω input-output resistance. The device requires no external bias on the output side and exhibits typical turn-on/turn-off times of 0.13 ms and 0.06 ms respectively at 5 mA LED drive.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Withstand Voltage | 60 V - Maximum continuous voltage across output terminals without breakdown |
| Max Output Current | 0.2 A - Sustained DC load current capability at TA = 25°C, derates above ambient |
| On-Resistance (RON) | 10 Ω max - Output conduction loss at 200 mA pulse; impacts power dissipation and voltage drop |
| Input Turn-On Current | 3 mA min - Minimum LED forward current required to reliably close the output switch |
| Input Turn-Off Voltage | 0.8 V max - Maximum LED forward voltage at which output reliably opens |
| Isolation Voltage | 3750 Vrms - Dielectric strength between input and output for 1 minute; meets UL1577 safety standard |
| Package | SO-4 Gull Wing - Surface-mount 4-pin small-outline package with RoHS-compliant lead finish |
Pinout & Package
ASSR-1218-503E uses a 4-pin Small Outline (SO-4) gull-wing surface-mount package with 2.54 mm pitch. Pin 1 and Pin 2 form the anode/cathode of the input LED; Pin 3 and Pin 4 are the bidirectional output terminals of the MOSFET switch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | LED Anode | Positive input terminal for infrared LED; connects to current-limiting resistor and logic-high source |
| Pin 2 | LED Cathode | Ground return for LED; enables CMOS/TTL-compatible 3–20 mA drive |
| Pin 3 | Output Terminal 1 | Bidirectional MOSFET drain/source; connects to one side of AC/DC load |
| Pin 4 | Output Terminal 2 | Bidirectional MOSFET drain/source; connects to other side of load; no polarity requirement |
Key Features
| Feature | Design Value |
|---|---|
| Optically isolated SPST switch | Eliminates electromagnetic interference and ground-loop issues in mixed-signal systems |
| CMOS-compatible input | Operates with ≤3 mA LED current - compatible with microcontroller GPIO without buffer stages |
| UL1577 & CSA certified insulation | Enables use in Class I/II medical and industrial equipment requiring reinforced isolation |
| No external output bias required | Simplifies PCB layout and reduces BOM count by eliminating gate drive circuitry |
| Gull-wing SO-4 footprint | Supports automated reflow assembly and provides mechanical robustness vs. DIP variants |
Applications
| Telecom Line Interface | Industrial PLC I/O Module |
|---|---|
Use Scenario: Isolating analog/digital signals between central office equipment and subscriber line cards. IC Role / Device Role / Timing Role: Solid-state relay providing galvanic isolation and signal path control for POTS line supervision and ringing detection. Use Value: Replaces bulky EMRs with 0.13 ms turn-on time, enabling faster loop diagnostics and reducing board space by >70%. | Use Scenario: Switching 24 V DC sensor inputs and actuator outputs in programmable logic controller backplanes. IC Role / Device Role / Timing Role: Bidirectional SPST isolator handling dry-contact simulation and field-side signal routing. Use Value: Delivers 3750 Vrms isolation without creepage/clearance compromises, meeting IEC 61000-4-5 surge immunity requirements. |
| Medical Patient Monitoring | Security System Zone Input |
Use Scenario: Isolating ECG/EEG electrode connections from digital processing circuitry in bedside monitors. IC Role / Device Role / Timing Role: Safety-isolated signal switch ensuring patient-connected circuits meet BF-rated isolation standards. Use Value: Certified to UL1577 and CSA Component Acceptance Notice #5 - eliminates need for external isolation transformers or optocoupler+MOSFET combos. | Use Scenario: Supervising wired intrusion detection zones (door/window contacts) in alarm panels. IC Role / Device Role / Timing Role: Dry-contact replacement for zone input buffering with built-in fault tolerance and leakage suppression. Use Value: 1 μA max output leakage ensures reliable open-circuit detection; 60 V withstand handles induced transients on long cable runs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar solid-state relay applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Toshiba TLP3558A | SO-6 package; 60 V/0.2 A; 10 Ω RON; 5 mA min IF(ON); 3750 Vrms isolation | Requires 2 additional pins for internal bypass capacitor; not pin-compatible with SO-4 layout | Select when needing integrated transient suppression or higher surge immunity margin |
| Vishay VO1263BA | DIP-6 package; 60 V/0.2 A; 12 Ω RON; 3 mA min IF(ON); 5000 Vrms isolation | Through-hole mounting only; larger footprint; higher creepage distance for enhanced safety spacing | Select for legacy through-hole designs or applications requiring >3750 Vrms isolation compliance |
Compared with TLP3558A and VO1263BA, the ASSR-1218-503E offers the smallest footprint (SO-4), lowest turn-on current (3 mA), and gull-wing surface-mount compatibility - making it optimal for space-constrained, high-density PCBs where reflow assembly and minimal layout change are priorities.
Availability
ASSR-1218-503E is available at Aetrix Electronics and suitable for telecommunications switching, industrial PLC I/O modules, medical patient monitoring interfaces, and security system zone inputs requiring stable component supply, RoHS compliance, and UL/CSA-certified isolation.
Supply support for ASSR-1218-503E 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 Inc. is a global semiconductor leader designing connectivity, infrastructure, and industrial signal-integrity solutions with emphasis on reliability and regulatory compliance.
The ASSR-12XX series is part of Broadcom's optocoupler and solid-state relay product line, engineered specifically for replacing electromechanical relays in safety-isolated, low-power signal switching applications across telecom, industrial, and medical end equipment.
FAQ
What is the minimum input current required to turn on the ASSR-1218-503E?
The ASSR-1218-503E requires a minimum input current of 3 mA through its infrared LED to reliably turn on the output MOSFET. While the device may activate at lower currents (≥0.5 mA), Broadcom specifies 3 mA as the guaranteed turn-on threshold across temperature and process variations. Operating at 5 mA ensures robust performance over the full –40°C to +85°C operating range and is recommended for production designs using the ASSR-1218-503E.
Does the ASSR-1218-503E support AC load switching?
Yes, the ASSR-1218-503E supports bidirectional AC load switching due to its symmetrical MOSFET output structure. It is rated for 60 V peak AC or DC output voltage and can handle zero-crossing and non-zero-crossing AC waveforms. However, its 0.2 A current rating applies to RMS values, and thermal derating must be applied per Figure 1 in the datasheet when operating at elevated ambient temperatures. The ASSR-1218-503E does not require external snubbers for typical 24–48 VAC control applications.
What is the isolation voltage rating of the ASSR-1218-503E and how is it certified?
The ASSR-1218-503E provides 3750 Vrms input-output isolation for 1 minute per UL 1577 and is approved under CSA Component Acceptance Notice #5. This rating is verified with pins 1–2 shorted (input side) and pins 3–4 shorted (output side). The isolation barrier meets material group IIIa per DIN VDE 0109 and has a comparative tracking index (CTI) of 175 V, qualifying it for reinforced insulation in medical BF-rated and industrial control applications. The ASSR-1218-503E is not AEC-Q100 qualified and is not intended for automotive use.
Can the ASSR-1218-503E replace a mechanical relay in a 24 V DC control circuit?
Yes, the ASSR-1218-503E is designed as a direct functional replacement for 1 Form A electromechanical relays in 24 V DC control circuits. It offers 60 V output withstand, 0.2 A continuous current, and <10 Ω on-resistance - sufficient for driving solenoids, indicator LEDs, and small DC motors. Unlike mechanical relays, the ASSR-1218-503E provides silent operation, infinite cycle life, and no contact bounce. Its 0.13 ms turn-on time enables precise timing control unattainable with EMRs, and the SO-4 footprint simplifies migration from through-hole relays using adapter layouts.
What are the thermal limitations of the ASSR-1218-503E during continuous operation?
The ASSR-1218-503E has a maximum junction temperature of 125°C and a specified operating ambient temperature range of –40°C to +85°C. Its maximum average output current decreases with rising ambient temperature, as shown in Figure 1 of the datasheet: at 25°C it supports 0.2 A, but at 70°C this drops to ~0.12 A. Power dissipation is limited to 400 mW. To maintain reliability, PCB layout must provide adequate copper area (e.g., 4-layer board with thermal vias) and avoid stacking heat-generating components adjacent to the ASSR-1218-503E.
ASSR-1218-503E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Broadcom Limited
- Series:
- ASSR
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Mounting Type:
- Surface Mount
- Circuit:
- SPST-NO (1 Form A)
- Output Type:
- AC, DC
- Voltage - Input:
- 1.3VDC
- Voltage - Load:
- 0 V ~ 60 V
- Load Current:
- 200 mA
- On-State Resistance (Max):
- 10 Ohms
- Termination Style:
- Gull Wing
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 4-SO
- Approval Agency:
- CSA, UL
- Grade:
- -
- Qualification:
- -
ASSR-1218-503E FAQ
1.How can I place an order for ASSR-1218-503E through Aetrix?
Please submit a Request for Quotation (RFQ) for ASSR-1218-503E on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for ASSR-1218-503E reliable?
The price and inventory of ASSR-1218-503E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ASSR-1218-503E is usually 5 days.
3.What payment methods are accepted for ASSR-1218-503E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ASSR-1218-503E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ASSR-1218-503E?
ASSR-1218-503E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ASSR-1218-503E order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for ASSR-1218-503E?
For technical support, including ASSR-1218-503E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ASSR-1218-503E requirements.
6.How does Aetrix verify that ASSR-1218-503E is sourced from the original manufacturer or authorized distributors?
All ASSR-1218-503E products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ASSR-1218-503E meets industry standards.
7.What is the process for return or replacement of ASSR-1218-503E?
All ASSR-1218-503E units undergo pre-shipment inspection (PSI). If there is an issue with ASSR-1218-503E, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The ASSR-1218-503E part is unused and in its original packaging.
Return procedure for ASSR-1218-503E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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