LAA126STR Equivalent & Substitute Parts

Part Overview

The LAA126STR is a solid-state relay (SSR) manufactured by Littelfuse, configured as a SPST-NO (Single Pole Single Throw - Normally Open) relay with dual channels in an 8-SMD surface mount package. This component is designed for AC and DC load switching applications with a maximum load voltage of 250V and load current of 170mA. The part is currently obsolete, making identification of suitable substitute components essential for ongoing system support and new design implementations.

Substiute Parts

LAA126STR

LittelfuseIn Stock: 1192LAA126STR Datasheet

Current PartRFQ

LH1522AACTR

Vishay Semiconductor Opto DivisionIn Stock: 3349LH1522AACTR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LAA126STR is determined by the following critical parameters:

• Circuit Configuration: SPST-NO (1 Form A) x 2 dual-channel architecture
• Package Type: 8-SMD (0.300", 7.62mm) surface mount with gull wing termination
• Input Voltage: 1.2VDC nominal control voltage
• Load Voltage Range: 0V to 250V AC/DC capability
• Load Current Capacity: Minimum 170mA switching capability
• On-State Resistance: Maximum 15 Ohms
• Mounting Compatibility: Surface mount PCB assembly

The LH1522AACTR from Vishay Semiconductor Opto Division qualifies as a substitute based on matching package geometry, circuit topology, mounting type, and termination style. While the substitute exhibits lower maximum load current (120mA) and reduced load voltage range (200V), these represent derating characteristics that may be acceptable depending on application requirements.

Parameter Comparison

Engineering Selection Recommendations

The LH1522AACTR represents the primary substitute for the obsolete LAA126STR. The substitute maintains identical package geometry, circuit topology, and mounting characteristics, enabling direct PCB footprint compatibility. The LH1522AACTR carries active product status with ROHS3 compliance, providing long-term availability and regulatory alignment.

Design considerations for substitution include load current derating from 170mA to 120mA and maximum load voltage reduction from 250V to 200V. Applications operating within these reduced specifications require no circuit modification. Applications exceeding these parameters necessitate alternative component selection or circuit redesign.

Frequently Asked Questions (FAQ)

Q: Can the LH1522AACTR be used as a direct replacement for the LAA126STR?

A: The LH1522AACTR provides physical and electrical compatibility for applications operating within its specified load current (120mA maximum) and load voltage (200V maximum) ratings. Direct PCB footprint compatibility exists due to identical 8-SMD package geometry and gull wing termination. Applications requiring the full 170mA or 250V specifications of the original part require alternative solutions.

Q: What are the key differences between these two SSR relays?

A: The primary differences are product status (obsolete vs. active), load current capacity (170mA vs. 120mA), maximum load voltage (250V vs. 200V), and on-state resistance (15 Ohms vs. 10 Ohms). Input voltage specifications are nearly identical (1.2VDC vs. 1.26VDC). Both components share identical package type, circuit configuration, and mounting characteristics.

Q: Are there any compliance or regulatory differences?

A: The LH1522AACTR carries ROHS3 compliance certification, while the LAA126STR does not specify RoHS status. Both components are REACH Unaffected and carry EAR99 ECCN classification. The substitute provides enhanced regulatory alignment for new designs and long-term supply chain stability.

Q: What packaging options are available for the LH1522AACTR?

A: The LH1522AACTR is supplied in Tape & Reel (TR) packaging format, suitable for automated PCB assembly processes. The LAA126STR packaging format is not specified in available documentation.

Q: How do the electrical characteristics compare for AC versus DC switching?

A: Both components support AC and DC load switching across their respective voltage and current ranges. The LH1522AACTR operates at identical AC/DC output capability within its 0V to 200V load voltage specification and 120mA maximum load current rating.