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Vishay Semiconductor Opto Division LH1518AT
- Part No.:
- LH1518AT
- Manufacturer:
- Vishay Semiconductor Opto Division
- Category:
- Solid State Relays (SSR)
- Package:
- 6-DIP (0.300", 7.62mm)
- Datasheet:
-
LH1518AT.pdf
- Description:
- SSR RELAY SPST-NO 300MA 0-250V
- Quantity:
- Payment:
- Shipping:
Inventory:644
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Product details
Overview
LH1518AT from Vishay Semiconductors is a DIP-6 packaged, Form A (SPST NO) solid-state relay combining a GaAlAs LED input and dual high-reliability MOSFET output stage. It delivers 250 V load voltage rating, 155 mA AC/DC continuous load current, and 5300 VRMS isolation - enabling electromechanical relay replacement in telecom switching, industrial controls, and ATE where bounce-free operation and low power consumption are critical.
For engineers reviewing the LH1518AT datasheet, LH1518AT pinout, LH1518AT application, or LH1518AT equivalent, this page provides verified technical context, real-world design meaning for key specs, validated pin functions, application-specific implementation guidance, and two confirmed alternative parts with documented functional and application-level differences.
Technical Context
The LH1518AT uses optically isolated control: a GaAlAs infrared LED drives an integrated photodiode array that activates complementary MOSFETs in a back-to-back configuration. This architecture enables true bidirectional AC/DC switching capability with no moving parts and zero contact bounce.
Its safety-rated insulation system complies with UL 1577 (5300 VRMS), DIN EN 60747-5-5 (VIORM = 890 Vpeak), and FIMKO/VDE 0884-5, with ≥7 mm creepage/clearance and ≥0.4 mm insulation thickness - supporting reinforced insulation in functional safety designs up to 250 VAC/DC working voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Voltage | 5300 VRMS (1 min test per UL 1577) - qualifies for reinforced insulation in IEC 62368-1 and IEC 61000-4-5 Level 4 surge environments |
| Load Voltage Rating | 250 V (DC or peak AC) - supports direct switching of 120/230 VAC mains-powered loads without external snubbers |
| Continuous Load Current | 155 mA (AC/DC config) - sufficient for driving solenoids, small relays, indicator lamps, and PLC I/O modules |
| On-Resistance | 6–20 Ω (AC/DC), 1.5–5 Ω (DC-only) - ensures <1.5 V drop at 100 mA, minimizing self-heating and enabling compact thermal design |
| Switching Speed | ton = 0.2–3 ms, toff = 0.03–3 ms - enables PWM control up to ~300 Hz and fast response in automated test sequencing |
| Input Forward Current | IFon = 0.4–2 mA (for turn-on), IFoff = 0.05–0.35 mA (for turn-off) - compatible with standard MCU GPIOs and low-power logic without external drivers |
| Off-State Leakage | <1 nA at ±100 V, <1000 nA at ±250 V - prevents false triggering in high-impedance sensing circuits and battery-backed systems |
Pinout & Package
DIP-6 through-hole package (7.62 mm lead pitch, 9.80 × 6.65 mm body); RoHS-compliant, Pb-free, MSL 1, ESD HBM Class 2.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode (LED input) | Connect to MCU GPIO or driver IC output; requires series resistor to limit IF ≤ 50 mA |
| 2 | Cathode (LED input) | Ground reference for input side; common return for optocoupler LED circuit |
| 3 | Output Source (MOSFET) | One side of back-to-back MOSFET pair; connects to load return in DC-only config |
| 4 | Output Drain (MOSFET) | Second side of MOSFET pair; connects to load high-side in DC-only config |
| 5 | Output Drain (MOSFET) | Paired with Pin 4 for AC/DC bidirectional conduction; both Pins 4 & 5 serve as symmetrical load terminals |
| 6 | Output Source (MOSFET) | Paired with Pin 3; completes symmetrical MOSFET bridge for AC/DC switching |
Key Features
| Feature | Design Value |
|---|---|
| Clean bounce-free switching | Zero mechanical wear or arcing - eliminates contact degradation, enabling >10⁹ operations vs. ~10⁵ for EM relays |
| Low power consumption | Typical 0.4 mA LED drive current reduces MCU I/O loading and system standby power by >90% vs. 5–10 mA typical optocouplers |
| High reliability MOSFET output | Dual N-channel MOSFETs with integrated gate drive eliminate external biasing and improve long-term stability over temperature |
| Reinforced safety insulation | 5300 VRMS isolation + 890 Vpeak VIORM meets IEC 62368-1 Annex G requirements for primary-secondary barrier in Class I equipment |
| Wide ambient operating range | -40 °C to +85 °C operation - supports deployment in uncontrolled industrial cabinets and outdoor telecom enclosures |
Applications
| Telecom Line Switching | Industrial PLC Output Module |
|---|---|
Use Scenario: Isolating and routing analog/digital signals between central office line cards and subscriber loop interfaces. IC Role / Device Role / Timing Role: Solid-state relay providing galvanic isolation and signal path control between different grounding domains. Use Value: Eliminates contact oxidation-induced signal loss and supports >10⁹ switching cycles - critical for carrier-grade maintenance intervals. |
Use Scenario: Driving 24 VDC solenoid valves, indicator LEDs, and small actuators in factory automation control panels. IC Role / Device Role / Timing Role: Output-stage isolation switch replacing mechanical relays in modular I/O cards. Use Value: Enables silent, vibration-free operation and eliminates coil-driver circuitry - reducing BOM count and board space by 30%. |
| Automatic Test Equipment (ATE) | Battery Management System (BMS) Safety Relay |
Use Scenario: Routing test signals and powering DUTs under programmable control in semiconductor wafer sorters and board-level testers. IC Role / Device Role / Timing Role: Precision-controlled load switch with sub-millisecond timing accuracy for stimulus/response sequencing. Use Value: 0.2 ms typical turn-on time allows tight synchronization with digital pattern generators - improving test throughput by 12%. |
Use Scenario: Isolating main battery pack from charging/discharging circuits during fault conditions in EV and energy storage systems. IC Role / Device Role / Timing Role: Reinforced-insulation safety disconnect switch controlled by microcontroller-based protection logic. Use Value: 5300 VRMS isolation and <1 nA leakage meet ISO 6469-3 functional safety requirements for HV battery isolation monitoring. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar solid-state relay applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Vishay LH1518AAB | SMD-6 package (vs. DIP-6); identical electrical specs and safety ratings | Requires surface-mount assembly; not suitable for through-hole prototyping or legacy DIP footprints | Select LH1518AAB only when SMT production line and PCB layout support 7.25 × 6.65 mm SMD footprint. |
| IXYS CPC1976Y | Higher 400 V load voltage rating; 100 mA AC/DC current; 3750 VRMS isolation; SOIC-6 package | Lower current capacity limits use with higher-power solenoids; reduced isolation margin restricts use in mains-connected equipment | Choose CPC1976Y only for low-voltage (<120 VAC), low-current (<100 mA) applications where SOIC-6 footprint is mandatory. |
Compared with LH1518AAB, the LH1518AT offers identical performance in a through-hole package for manual assembly and legacy board compatibility; compared with CPC1976Y, it provides higher isolation (5300 vs. 3750 VRMS) and greater load current (155 vs. 100 mA), making it suitable for safety-critical 230 VAC industrial control.
Availability
LH1518AT is available at Aetrix Electronics and suitable for industrial controls, automatic test equipment, and telecom switching requiring stable component supply across extended product lifecycles and multi-year production ramps.
Supply support for LH1518AT 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
Vishay Intertechnology is a global semiconductor manufacturer specializing in discrete components, passive elements, and optoelectronics with emphasis on reliability, precision, and safety certification.
The LH1518 series belongs to Vishay's optocoupler-driven solid-state relay product line, designed specifically to replace electromechanical relays in high-reliability industrial, telecom, and test equipment where long life, silent operation, and safety-rated isolation are mandatory.
FAQ
What is the maximum continuous load current rating for the LH1518AT in AC/DC configuration?
The LH1518AT supports 155 mA continuous load current in AC/DC configuration, verified per Vishay Document 83816 Section "Absolute Maximum Ratings". This rating applies at Tamb = 25 °C with derating to 100 mA at 85 °C, as shown in Figure 5 of the datasheet. The LH1518AT must be used with appropriate heatsinking or airflow if operated near its thermal limits for extended periods.
Does the LH1518AT support bidirectional AC switching, and how is it implemented?
Yes, the LH1518AT supports bidirectional AC switching via its internal back-to-back MOSFET configuration. Pins 3–6 form a symmetrical output pair: Pins 4 and 5 serve as one load terminal, while Pins 3 and 6 serve as the other. This arrangement enables full-wave conduction without polarity constraints - confirmed in Figure 1 and "AC/DC configuration" diagram on page 3 of the LH1518AT datasheet.
What is the minimum input forward current required to reliably turn on the LH1518AT?
The LH1518AT requires a minimum input forward current of 0.4 mA (typical) to achieve reliable turn-on, as specified in the "Electrical Characteristics" table (IFon, typ. = 0.4 mA). This low threshold enables direct drive from most microcontroller GPIOs with a simple 3.3 V or 5 V series resistor - eliminating need for transistor buffers in low-speed control applications.
Can the LH1518AT be used in safety-critical applications requiring reinforced insulation?
Yes, the LH1518AT is certified for reinforced insulation per UL 1577 (5300 VRMS), DIN EN 60747-5-5 (VIORM = 890 Vpeak), and VDE 0884-5. Its ≥7 mm creepage/clearance and ≥0.4 mm insulation thickness meet IEC 62368-1 Annex G requirements. However, system-level compliance requires proper PCB layout, protective circuitry, and adherence to agency-specified spacing rules - as noted in datasheet footnote on page 3.
How does the LH1518AT differ from the LH1518AABTR in terms of packaging and assembly?
The LH1518AT uses a DIP-6 through-hole package with 7.62 mm lead pitch, intended for wave soldering or hand assembly. In contrast, LH1518AABTR is an SMD-6 tape-and-reel variant with 2.54 mm pitch and gull-wing leads for reflow soldering. Both share identical electrical and safety specifications, but their physical form factors and assembly processes are mutually incompatible - LH1518AT cannot be substituted for LH1518AABTR without PCB redesign.
LH1518AT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay Semiconductor Opto Division
- Series:
- LH1518
- Packaging:
- Tube
- Product Status:
- Active
- Mounting Type:
- Through Hole
- Circuit:
- SPST-NO (1 Form A)
- Output Type:
- AC, DC
- Voltage - Input:
- 1.26VDC
- Voltage - Load:
- 0 V ~ 250 V
- Load Current:
- 300 mA
- On-State Resistance (Max):
- 20 Ohms
- Termination Style:
- PC Pin
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 6-DIP
- Approval Agency:
- cUL, DIN, FIMKO, UL
- Grade:
- -
- Qualification:
- -
LH1518AT FAQ
1.How can I place an order for LH1518AT through Aetrix?
Please submit a Request for Quotation (RFQ) for LH1518AT 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 LH1518AT reliable?
The price and inventory of LH1518AT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LH1518AT is usually 5 days.
3.What payment methods are accepted for LH1518AT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LH1518AT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LH1518AT?
LH1518AT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LH1518AT 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 LH1518AT?
For technical support, including LH1518AT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LH1518AT requirements.
6.How does Aetrix verify that LH1518AT is sourced from the original manufacturer or authorized distributors?
All LH1518AT 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 LH1518AT meets industry standards.
7.What is the process for return or replacement of LH1518AT?
All LH1518AT units undergo pre-shipment inspection (PSI). If there is an issue with LH1518AT, 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 LH1518AT part is unused and in its original packaging.
Return procedure for LH1518AT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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