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Vishay Semiconductor Opto Division LH1546AT
- Part No.:
- LH1546AT
- Manufacturer:
- Vishay Semiconductor Opto Division
- Category:
- Solid State Relays (SSR)
- Package:
- 6-DIP (0.300", 7.62mm)
- Datasheet:
-
LH1546AT.pdf
- Description:
- SSR RELAY SPST-NO 120MA 0-350V
- Quantity:
- Payment:
- Shipping:
Inventory:1,035
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Product details
Overview
LH1546AT from Vishay Semiconductors is a 1-Form-A solid-state relay (SSR) with GaAlAs LED input and dual-MOSFET output, delivering 350 V load voltage, 120 mA AC/DC load current, and 22 Ω typical on-resistance - used for bounce-free telecom switching and ground fault isolation in industrial control interfaces.
For engineers reviewing the LH1546AT datasheet, LH1546AT pinout, LH1546AT application, or LH1546AT equivalent, this SSR provides verified 5300 VRMS isolation, clean DC-only configuration operation up to 200 mA, and DIP-6 through-hole packaging compatible with legacy relay footprints and safety-critical instrumentation designs.
Technical Context
The LH1546AT integrates an infrared LED coupled optically to a pair of back-to-back MOSFETs, enabling bidirectional AC/DC switching without mechanical contacts. Its isolation barrier meets UL, cUL, VDE, BSI, and FIMKO safety standards with 7 mm creepage/clearance and ≥0.4 mm insulation thickness.
It operates across –40 °C to +85 °C ambient, supports 0.13 ms typical turn-on and 0.05 ms typical turn-off times at 5 mA LED drive, and maintains <1 nA off-state leakage at ±100 V - critical for high-impedance sensing and low-power fault detection circuits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Voltage | 5300 VRMS - enables safe separation between control logic and 350 V AC/DC loads per UL1577 and IEC 60747-5-5 |
| Load Voltage | 350 V - supports direct switching of telecom line interfaces and industrial AC mains-sensing circuits |
| Load Current | 120 mA (AC/DC), 200 mA (DC only) - sufficient for driving solenoids, pilot relays, and PLC input modules |
| On-Resistance | 22 Ω typical (AC/DC), 5.2 Ω typical (DC only) - minimizes power loss and self-heating in continuous-duty applications |
| Turn-On/Off Time | 0.13 ms / 0.05 ms typical - ensures precise timing control in data acquisition and protection sequencing |
| Input Forward Voltage | 1.4 V typical at 10 mA - compatible with 3.3 V and 5 V microcontroller GPIO without external driver stages |
| Off-State Leakage | <1 nA at ±100 V - preserves signal integrity in high-impedance analog monitoring paths |
Pinout & Package
DIP-6 through-hole package (7.62 mm lead pitch), 9.80 mm × 6.65 mm body, 3.55 mm height, leads coplanar ≤0.1 mm - designed for wave soldering per J-STD-020 and compatible with standard 0.1″ grid PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Anode) | LED Anode Input | Accepts 5–50 mA forward current; connects to MCU GPIO or driver stage for SSR activation |
| 2 (Cathode) | LED Cathode Input | Reference return path for LED; ties to ground or active-low driver sink |
| 3 (Load –) | Output Terminal (AC/DC) | Common source node for dual-MOSFET output; connects to load return side |
| 4 (Load +) | Output Terminal (AC/DC) | Drain connection for both MOSFETs; carries full load current to/from external circuit |
| 5 (NC) | No Connect | Internally unconnected; must remain floating - no routing or grounding permitted |
| 6 (NC) | No Connect | Internally unconnected; must remain floating - no routing or grounding permitted |
Key Features
| Feature | Design Value |
|---|---|
| Clean bounce-free switching | Eliminates contact arcing and EMI in telecom line testing and automated test equipment (ATE) |
| 5300 VRMS isolation rating | Meets reinforced insulation requirements for Class I equipment in telecom and industrial environments |
| Low 0.3 mA typical turn-on LED current | Reduces MCU I/O loading and enables direct drive from low-power microcontrollers like MSP430 or STM32L |
| DC-only configuration mode | Enables 200 mA load current and 5.2 Ω RON - optimized for battery-powered PLC I/O and sensor excitation |
| 175 °C safety temperature rating | Supports reliable operation in enclosed enclosures with elevated ambient temperatures up to +85 °C |
Applications
| Telecom Line Switching | Ground Fault Detection Interface |
|---|---|
|
Use Scenario: Isolating and switching POTS line signals during loopback testing and DSLAM maintenance. IC Role / Device Role / Timing Role: Solid-state relay providing galvanic isolation and zero-crossing–free switching between test equipment and live telephone lines. Use Value: Eliminates mechanical relay wear and contact oxidation while maintaining 350 V withstand capability required for telco central office environments. |
Use Scenario: Monitoring insulation resistance in motor windings or solar array strings using high-voltage bias injection. IC Role / Device Role / Timing Role: High-isolation switch enabling safe application of test voltage without coupling noise into measurement circuitry. Use Value: <1 nA off-state leakage preserves accuracy of picoamp-level leakage current measurements under ±350 V bias conditions. |
| Industrial PLC Input Module | Instrumentation Signal Routing |
|
Use Scenario: Conditioning 24 V DC sensor inputs in programmable logic controllers with field-side isolation. IC Role / Device Role / Timing Role: Input-stage SSR replacing optocoupler + discrete transistor stages for simplified, robust channel isolation. Use Value: 200 mA DC-only load current and 5.2 Ω RON reduce heat generation and eliminate need for heatsinking in dense I/O modules. |
Use Scenario: Multiplexing high-impedance analog signals (e.g., thermocouple or strain gauge outputs) in precision data loggers. IC Role / Device Role / Timing Role: Low-leakage, low-capacitance switch isolating signal paths to prevent cross-talk and offset drift. Use Value: 6 pF output capacitance at 50 V and 0.4 pF input-to-output capacitance minimize settling time and maintain >100 dB CMRR in µV-level measurements. |
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 VO3120 | Lower 400 VRMS isolation (vs. 5300 VRMS); 1.2 Ω RON; DIP-6 package | Targeted at lower-voltage industrial controls; lacks UL/VDE certification for telecom use | Select VO3120 only when 400 V isolation suffices and sub-Ω on-resistance is prioritized over safety certification |
| IXYS CPC1976Y | Higher 6000 VRMS isolation; 350 V load voltage; SMD-6 only; no DIP-6 option | Requires PCB redesign for surface-mount assembly; better suited for new compact designs than drop-in replacement | Choose CPC1976Y when upgrading to RoHS-compliant SMD layout and needing higher isolation margin than LH1546AT offers |
Compared with VO3120 and CPC1976Y, the LH1546AT uniquely balances certified 5300 VRMS isolation, DIP-6 through-hole compatibility, and dual-mode (AC/DC + DC-only) operation - making it the only option supporting legacy telecom equipment upgrades without footprint or safety requalification.
Availability
LH1546AT is available at Aetrix Electronics and suitable for telecom line switching, ground fault detection interfaces, and industrial PLC input modules requiring stable component supply, long-term lifecycle support, and UL/VDE-certified isolation performance.
Supply support for LH1546AT 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, optoelectronics, and passive devices with emphasis on reliability, safety certification, and high-voltage isolation.
The LH1546AT belongs to Vishay's LH-series solid-state relay family, engineered specifically for replacing electromechanical relays in safety-critical telecom, instrumentation, and industrial control systems where bounce-free operation and regulatory compliance are mandatory.
FAQ
What is the maximum continuous load current rating for LH1546AT in AC/DC configuration?
The LH1546AT supports 120 mA continuous load current in AC/DC configuration, verified per IEC 60747-5-5 at Tamb = 25 °C. Derating applies above 25 °C - at 85 °C ambient, max load current drops to ~80 mA per Figure 5 in the official datasheet (Document Number: 83838, Rev. 2.2).
Does LH1546AT support DC-only load switching, and what are its benefits?
Yes, the LH1546AT supports DC-only configuration with 200 mA continuous load current and 5.2 Ω typical on-resistance - enabled by internal MOSFET topology that bypasses AC-blocking constraints. This mode reduces conduction loss and thermal stress in battery-powered or low-voltage industrial I/O applications where AC capability is unnecessary.
What safety certifications does LH1546AT hold, and which agencies granted them?
The LH1546AT is certified by UL, cUL, VDE, BSI, and FIMKO for reinforced insulation. These approvals validate its 5300 VRMS isolation, 7 mm creepage/clearance, and 0.4 mm insulation thickness per IEC 60747-5-5 and UL1577 - confirming suitability for use in Class I equipment in telecom and industrial settings.
Can LH1546AT be driven directly from a 3.3 V microcontroller GPIO without external circuitry?
Yes, the LH1546AT requires only 0.3 mA typical forward current to turn on (IFon), and its 1.4 V typical forward voltage at 10 mA allows direct drive from 3.3 V GPIO pins using a series resistor (e.g., 10 kΩ for ~0.23 mA). No buffer or transistor stage is needed for basic on/off control in low-speed applications.
What is the meaning of pins 5 and 6 being marked "NC" on the LH1546AT DIP-6 package?
Pins 5 and 6 on the LH1546AT are internally not connected - they serve no electrical function and must remain unconnected in the PCB layout. Routing, grounding, or tying them to any potential violates the device's safety isolation barrier and voids UL/VDE certification. The LH1546AT relies solely on pins 1–4 for full functionality.
LH1546AT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay Semiconductor Opto Division
- Series:
- LH1546
- 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 ~ 350 V
- Load Current:
- 120 mA
- On-State Resistance (Max):
- 28 Ohms
- Termination Style:
- PC Pin
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 6-DIP
- Approval Agency:
- BSI, cUL, FIMKO, UL, VDE
- Grade:
- -
- Qualification:
- -
LH1546AT FAQ
1.How can I place an order for LH1546AT through Aetrix?
Please submit a Request for Quotation (RFQ) for LH1546AT 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 LH1546AT reliable?
The price and inventory of LH1546AT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LH1546AT is usually 5 days.
3.What payment methods are accepted for LH1546AT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LH1546AT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LH1546AT?
LH1546AT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LH1546AT 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 LH1546AT?
For technical support, including LH1546AT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LH1546AT requirements.
6.How does Aetrix verify that LH1546AT is sourced from the original manufacturer or authorized distributors?
All LH1546AT 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 LH1546AT meets industry standards.
7.What is the process for return or replacement of LH1546AT?
All LH1546AT units undergo pre-shipment inspection (PSI). If there is an issue with LH1546AT, 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 LH1546AT part is unused and in its original packaging.
Return procedure for LH1546AT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LH1546AT Tags
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