LH1540ACD Equivalent & Substitute Parts

Part Overview

The LH1540ACD is a Solid State Relay (SSR) manufactured by Vishay Semiconductor Opto Division, configured as a SPST-NO (1 Form A) relay in an 8-PowerSOIC package. This component is designed for switching applications with AC and DC loads up to 350V at 110mA maximum load current. The product is currently obsolete, making identification of compatible substitute parts essential for system maintenance, redesign, and procurement planning.

Substiute Parts

LH1540ACD

Vishay Semiconductor Opto DivisionIn Stock: 1463LH1540ACD Datasheet

Current PartRFQ

AQY210S

Panasonic Electric WorksIn Stock: 16871AQY210S Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LH1540ACD is determined by strict alignment of electrical and mechanical parameters. The following criteria establish functional equivalence:

Electrical Compatibility Requirements:

• Circuit configuration must be SPST-NO (1 Form A)
• Output type must support both AC and DC switching
• Input voltage must be compatible with 1.15VDC control signal
• Load voltage range must encompass 0 V ~ 350 V
• Load current capability must meet or exceed 110 mA
• On-state resistance must not exceed 18 Ohms to maintain acceptable voltage drop

Mechanical Compatibility Requirements:

• Surface mount mounting type
• Gull wing termination style
• Package footprint must be compatible with 8-PowerSOIC or equivalent pinout

Compliance Requirements:

• RoHS3 compliance mandatory
• REACH compliance status must be unaffected or compliant

The AQY210S from Panasonic Electric Works meets all established substitution criteria and is identified as the manufacturer-recommended equivalent.

Parameter Comparison

Engineering Selection Recommendations

The AQY210S is the manufacturer-recommended substitute for the obsolete LH1540ACD. Both components maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment for new designs and legacy system updates.

The AQY210S provides electrical performance that meets or exceeds the LH1540ACD specifications across all critical parameters: input voltage compatibility (1.14VDC vs. 1.15VDC), load current capability (120mA vs. 110mA), and load voltage range (0-350V match). The on-state resistance of 25 Ohms is within acceptable operating margins for the specified 110mA load current.

The primary consideration is package footprint difference: the AQY210S uses a 4-SOP package (0.173", 4.40mm) compared to the LH1540ACD's 8-PowerSOIC package (0.220", 5.59mm). PCB layout and pinout verification is required before implementation in existing designs. The AQY210S PhotoMOS™ series represents current active production status, ensuring long-term availability and supply chain stability.

Frequently Asked Questions (FAQ)

Q: Can the AQY210S directly replace the LH1540ACD without PCB modifications?

A: Electrical compatibility is confirmed across all functional parameters. However, package geometry differs (4-SOP vs. 8-PowerSOIC), requiring PCB layout assessment and potential footprint redesign. Pinout verification is mandatory before board-level substitution.

Q: What is the significance of the on-state resistance difference (18 Ohms vs. 25 Ohms)?

A: The AQY210S on-state resistance of 25 Ohms remains within acceptable operating parameters for the 110mA load current specification. Voltage drop across the relay will be slightly higher (2.75V vs. 1.98V at maximum load), which must be evaluated within the context of the complete circuit design.

Q: Why is the LH1540ACD obsolete and what does this mean for procurement?

A: Obsolete status indicates the manufacturer has discontinued production. The AQY210S, with active product status from Panasonic Electric Works, provides a viable path for new designs and system updates. Existing inventory of LH1540ACD components may be available through authorized distributors, but long-term availability cannot be guaranteed.

Q: Are there compliance differences between the two parts?

A: Both components are ROHS3 compliant and REACH unaffected, meeting current regulatory requirements for electronic component manufacturing and use in regulated markets.

Q: What load current margin exists with the AQY210S?

A: The AQY210S is rated for 120mA maximum load current, providing a 10mA margin above the LH1540ACD's 110mA requirement. This margin accommodates normal component tolerance variations and provides operational headroom.