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Vishay Semiconductor Opto Division LH1540AAB
- Part No.:
- LH1540AAB
- Manufacturer:
- Vishay Semiconductor Opto Division
- Category:
- Solid State Relays (SSR)
- Package:
- 6-SMD (0.300", 7.62mm)
- Datasheet:
-
LH1540AAB.pdf
- Description:
- SSR RELAY SPST-NO 120MA 0-350V
- Quantity:
- Payment:
- Shipping:
Inventory:1,358
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Product details
Overview
LH1540AAB from Vishay Semiconductors is a 1-Form-A solid-state relay (SSR) with GaAlAs LED input and MOSFET output, rated for 350 V load voltage and 120 mA AC/DC continuous load current, featuring 5300 VRMS isolation and 22 Ω typical on-resistance - used in telecom switching and ground fault protection circuits.
For engineers reviewing the LH1540AAB datasheet, LH1540AAB pinout, LH1540AAB application, or LH1540AAB equivalent, this device is selected for high-isolation, bounce-free switching in safety-critical industrial controls and instrumentation where electromechanical relay replacement is required.
Technical Context
The LH1540AAB integrates an optically coupled GaAlAs LED driver and dual-MOSFET output stage configured as a normally open SPST switch. Its isolation barrier meets UL, cUL, VDE, and FIMKO safety standards with 5300 VRMS withstand voltage and ≥7 mm creepage/clearance.
It supports two load configurations: AC/DC (120 mA, 22 Ω RON) and DC-only (250 mA, 5.2 Ω RON), with turn-on/turn-off times of 0.13 ms and 0.05 ms respectively at 5 mA LED drive - enabling fast, low-noise switching in telecom line interface cards.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Isolation Voltage | 5300 VRMS - enables safe separation between control and high-voltage load circuits per UL1577 and DIN EN 60747-5-5. |
| Load Voltage Rating | 350 V - supports direct switching of telecom ring signals and industrial AC mains-sensed lines. |
| Continuous Load Current | 120 mA (AC/DC) - sufficient for driving telecom subscriber line interface circuit (SLIC) supervision loads. |
| On-Resistance | 22 Ω typical (AC/DC) - limits power dissipation to ≤550 mW at full load, reducing thermal stress in compact PCB layouts. |
| Turn-On Time | 0.13 ms typical - ensures rapid response in ground fault detection systems requiring sub-millisecond actuation. |
| Input LED Forward Voltage | 1.4 V typical at 10 mA - compatible with standard 3.3 V or 5 V microcontroller GPIO without external level-shifting. |
| Off-State Leakage | <1 nA at ±100 V - maintains high impedance integrity in precision instrumentation signal paths. |
Pinout & Package
SMD-6 surface-mount package with gull-wing leads, 7.62 mm pitch, 9.80 mm × 6.65 mm footprint, and 0.25 mm lead thickness - optimized for automated assembly and high-density board layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Anode) | LED Anode Input | Accepts 5–50 mA forward current; connects to MCU GPIO or driver IC for optical activation. |
| 2 (Cathode) | LED Cathode Input | Reference return for LED drive; requires current-limiting resistor to set IFon threshold (~0.3 mA). |
| 3 (Source) | MOSFET Source Terminal | Common reference node for load return path; tied to system ground in DC-only configuration. |
| 4 (Drain) | MOSFET Drain Terminal | High-side load connection point; carries full 350 V load voltage and 120 mA current. |
| 5 (Load +) | AC/DC Load Terminal (+) | Used only in AC/DC mode; connects to positive side of bidirectional load (e.g., telecom ring line). |
| 6 (Load –) | AC/DC Load Terminal (–) | Used only in AC/DC mode; completes bidirectional load path with Pin 5 for true AC switching. |
Key Features
| Feature | Design Value |
|---|---|
| Clean bounce-free switching | Eliminates contact arcing and EMI in telecom line testing equipment, ensuring reliable state transitions without signal corruption. |
| 5300 VRMS isolation | Meets reinforced insulation requirements for Class I equipment in telecom central office and industrial PLC backplanes. |
| Low 0.3 mA turn-on LED current | Reduces controller-side power consumption and enables direct drive from ultra-low-power microcontrollers (e.g., ARM Cortex-M0+). |
| 7 mm creepage & clearance | Supports 350 V working voltage in pollution degree 2 environments without conformal coating or spacing adjustments. |
| 120 mA AC/DC load rating | Handles SLIC loop supervision loads and alarm circuit actuation in PBX and VoIP gateway designs without derating. |
Applications
| Telecom Line Interface | Ground Fault Detection |
|---|---|
|
Use Scenario: Isolating and switching analog ring/signal paths in VoIP gateways and DSLAM line cards. IC Role / Device Role / Timing Role: Solid-state relay providing galvanic isolation and SPST switching between controller logic and 48 V/90 V AC telecom lines. Use Value: Replaces electromechanical relays with 0.13 ms turn-on time and no contact wear, extending field service life beyond 10⁹ cycles. |
Use Scenario: Monitoring leakage current across insulated motor windings or solar panel strings. IC Role / Device Role / Timing Role: High-impedance isolation switch enabling safe sampling of floating high-voltage nodes by low-voltage ADCs. Use Value: <1 nA off-state leakage preserves measurement accuracy in μA-range fault current detection circuits. |
| Industrial Security Panel | Test Equipment Relay Matrix |
|
Use Scenario: Controlling siren outputs, door lock actuators, and sensor zone isolation in fire/alarm control panels. IC Role / Device Role / Timing Role: Safety-rated SSR isolating 24 V DC control logic from 120 V AC alarm loads and solenoid drivers. Use Value: UL/cUL/VDE certification allows single-component compliance with EN 50131 and UL 60950-1 system-level safety requirements. |
Use Scenario: Building reconfigurable signal routing matrices in automated test equipment (ATE) for semiconductor validation. IC Role / Device Role / Timing Role: Low-capacitance (6 pF at 50 V) SSR minimizing signal distortion during high-frequency analog path switching. Use Value: 39 pF output capacitance at 1 V enables clean switching of 1 MHz test signals without phase shift or settling delay. |
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 LH1540AABTR | Identical electrical specs and SMD-6 package; supplied in tape-and-reel (1000 units/reel) vs. tube (50 units/tube) for automated placement. | No functional difference; selected when high-volume SMT production requires reel-fed feeders. | Choose LH1540AABTR for pick-and-place assembly; LH1540AAB for prototyping or low-volume hand-soldering. |
| Vishay LH1540AT | DIP-6 through-hole package (7.62 mm pitch), same isolation and load ratings, but larger footprint and higher thermal mass. | Preferred in legacy industrial controllers and test fixtures where manual assembly or socketing is required. | Select LH1540AT when board layout mandates through-hole mounting or thermal cycling robustness exceeds SMD-6 requirements. |
Compared with LH1540AAB, LH1540AABTR offers identical performance in automated manufacturing contexts, while LH1540AT provides mechanical reliability in vibration-prone environments - neither is pin-compatible due to differing package types (SMD-6 vs. DIP-6), requiring separate PCB footprints.
Availability
LH1540AAB is available at Aetrix Electronics and suitable for telecom switching, ground fault detection, and industrial security systems requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for LH1540AAB 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, sensors, and optoelectronics with emphasis on reliability and safety-certified devices.
The LH1540 series belongs to Vishay's high-isolation solid-state relay product line, designed specifically for replacing electromechanical relays in telecom infrastructure, industrial safety systems, and precision instrumentation where bounce-free, long-life switching is critical.
FAQ
What is the maximum load voltage rating for the LH1540AAB?
The LH1540AAB has a maximum DC or peak AC load voltage rating of 350 V. This value is specified under absolute maximum ratings and applies to both AC/DC and DC-only configurations. Exceeding this voltage risks permanent breakdown of the internal MOSFET output stage, even if current remains within limits. The LH1540AAB must be used with appropriate snubbers or clamping circuits when switching inductive loads near this rating.
Does the LH1540AAB support AC load switching?
Yes, the LH1540AAB supports AC load switching in its AC/DC configuration using Pins 5 and 6 as complementary load terminals. In this mode, it delivers 120 mA continuous current with 22 Ω typical on-resistance and zero-crossing–free operation. It is not a zero-crossing SSR, so it switches asynchronously - suitable for telecom ring signal control but requiring external filtering for noise-sensitive AC applications.
What is the minimum LED forward current required to turn on the LH1540AAB?
The LH1540AAB requires a typical forward current of 0.3 mA to initiate turn-on, with a maximum of 2 mA guaranteed across temperature. This low drive requirement allows direct interfacing with low-power microcontrollers without additional driver stages. At 25 °C, 0.3 mA is sufficient to achieve full conduction; however, design margins should account for increased IFon up to 0.5 mA at -40 °C per Fig. 8 in the datasheet.
How does the LH1540AAB differ from the LH1540AABTR?
The LH1540AAB and LH1540AABTR share identical electrical specifications, thermal performance, and SMD-6 package dimensions. The sole difference is packaging: LH1540AAB ships in tubes (50 units), while LH1540AABTR is supplied in tape-and-reel format (1000 units/reel) for automated SMT assembly. Both part numbers use the same die and undergo identical qualification testing per Vishay Document 83833 Rev. 2.2.
Is the LH1540AAB certified for safety standards like UL and VDE?
Yes, the LH1540AAB is certified to UL 1577 (5300 VRMS), cUL, DIN EN 60747-5-5 (VDE 0884), and FIMKO standards. These certifications cover reinforced insulation, partial discharge limits, and transient voltage withstand (8000 VPEAK). Certification applies specifically to the LH1540AAB variant and is documented in Vishay's safety report referenced in datasheet section "Agency Approvals".
LH1540AAB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay Semiconductor Opto Division
- Series:
- LH1540
- Packaging:
- Tube
- Product Status:
- Active
- Mounting Type:
- Surface Mount
- 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):
- 20 Ohms
- Termination Style:
- Gull Wing
- Operating Temperature:
- -40°C ~ 85°C
- Supplier Device Package:
- 6-SMD
- Approval Agency:
- cUL, DIN, FIMKO, UL
- Grade:
- -
- Qualification:
- -
LH1540AAB FAQ
1.How can I place an order for LH1540AAB through Aetrix?
Please submit a Request for Quotation (RFQ) for LH1540AAB 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 LH1540AAB reliable?
The price and inventory of LH1540AAB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LH1540AAB is usually 5 days.
3.What payment methods are accepted for LH1540AAB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LH1540AAB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LH1540AAB?
LH1540AAB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LH1540AAB 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 LH1540AAB?
For technical support, including LH1540AAB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LH1540AAB requirements.
6.How does Aetrix verify that LH1540AAB is sourced from the original manufacturer or authorized distributors?
All LH1540AAB 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 LH1540AAB meets industry standards.
7.What is the process for return or replacement of LH1540AAB?
All LH1540AAB units undergo pre-shipment inspection (PSI). If there is an issue with LH1540AAB, 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 LH1540AAB part is unused and in its original packaging.
Return procedure for LH1540AAB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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