LAA120LS Solid State Relay - Equivalent & Substitute Parts

Part Overview

The LAA120LS is an active SPST-NO (Single Pole Single Throw - Normally Open) solid state relay manufactured by IXYS Integrated Circuits Division. This surface mount component operates with a 1.2VDC input signal and controls AC/DC loads up to 250V at 150mA. The device is packaged in an 8-SMD (0.300", 7.62mm) gull wing configuration suitable for automated assembly processes. Finding equivalent parts may be necessary due to supply constraints, lead time requirements, or design optimization needs while maintaining functional compatibility.

Substiute Parts

LAA120LS

IXYS Integrated Circuits DivisionIn Stock: 1968LAA120LS Datasheet

Current PartRFQ

LH1505AAC

Vishay Semiconductor Opto DivisionIn Stock: 1443LH1505AAC Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LAA120LS is determined by strict adherence to the following electrical and mechanical parameters:

Critical Substitution Criteria:

• Circuit configuration must be SPST-NO (1 Form A) x 2
• Package type must be 8-SMD with gull wing termination
• Load voltage range must encompass 0V ~ 250V
• Input voltage must be compatible with 1.2VDC control signal
• Load current capability must meet or exceed 150mA requirement
• Surface mount mounting type must be maintained
• Output type must support both AC and DC loads

The LH1505AAC from Vishay Semiconductor Opto Division qualifies as a manufacturer-recommended substitute. While the load current rating is 120mA (lower than the 150mA of the LAA120LS), the part maintains identical circuit configuration, package geometry, voltage specifications, and termination style. The on-state resistance of 15 Ohms is superior to the 25 Ohms maximum of the primary part.

Parameter Comparison

Engineering Selection Recommendations

Both the LAA120LS and LH1505AAC are active products with ROHS3 compliance and unlimited moisture sensitivity ratings, making them suitable for current production designs. The LH1505AAC offers improved on-state resistance characteristics (15 Ohms vs. 25 Ohms maximum), which reduces power dissipation in the relay circuit. The input voltage specification of 1.26VDC for the LH1505AAC is marginally higher than the LAA120LS at 1.2VDC but remains compatible with standard 1.2V to 1.5V control signal ranges.

The primary consideration for substitution is the load current rating differential: the LH1505AAC is rated for 120mA versus the LAA120LS at 150mA. Selection between these parts should be based on actual circuit load current requirements. If the application requires sustained operation at currents exceeding 120mA, the LAA120LS is the appropriate choice. For applications operating at or below 120mA, the LH1505AAC provides equivalent functionality with superior electrical characteristics.

Frequently Asked Questions (FAQ)

Q: Can the LH1505AAC directly replace the LAA120LS in existing designs?

A: Direct replacement is possible if the circuit load current does not exceed 120mA. The identical 8-SMD gull wing package, SPST-NO configuration, and 0V ~ 250V load voltage range ensure mechanical and electrical compatibility. PCB layout and solder reflow profiles remain unchanged.

Q: What is the significance of the input voltage difference (1.2VDC vs. 1.26VDC)?

A: The 0.06VDC difference is negligible in practical applications. Standard control signal sources (1.2V to 1.5V logic levels) will reliably trigger both devices. This parameter does not affect substitution feasibility.

Q: How does the on-state resistance difference impact circuit performance?

A: The LH1505AAC's 15 Ohms maximum on-state resistance versus the LAA120LS's 25 Ohms results in lower power dissipation across the relay contacts. For a 120mA load, this represents a reduction from 0.36W to 0.216W maximum dissipation, improving thermal efficiency.

Q: Are there packaging or handling differences between these parts?

A: Both parts are supplied in tube packaging with MSL 1 (Unlimited) moisture sensitivity ratings. Storage, handling, and reflow requirements are identical. No special precautions are required when transitioning between manufacturers.

Q: What load current applications favor each part?

A: The LAA120LS is specified for applications requiring up to 150mA continuous load current. The LH1505AAC is suitable for applications up to 120mA. Applications with peak currents exceeding 120mA or sustained operation near 150mA should use the LAA120LS to ensure reliable operation within rated specifications.