HSR412S Solid State Relay - Equivalent & Substitute Parts

Part Overview

The HSR412S is a Surface Mount Solid State Relay (SSR) manufactured by onsemi, configured as a SPST-NO (Single Pole Single Throw - Normally Open) relay with 1 Form A circuit. This component is designed for AC and DC load switching applications with a maximum load voltage range of 0-400V and load current capacity of 140mA. The HSR412S is classified as obsolete, making identification of functionally equivalent substitute components essential for ongoing design support, maintenance, and production continuity.

Substiute Parts

HSR412S

onsemiIn Stock: 1886HSR412S Datasheet

Current PartRFQ

LH1540AAB

Vishay Semiconductor Opto DivisionIn Stock: 3432LH1540AAB Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the HSR412S is determined by strict alignment of the following critical parameters:

• Circuit Configuration: Must be SPST-NO (1 Form A) to maintain identical switching topology
• Output Type: Must support both AC and DC load switching
• Package / Case: Must be 6-SMD (0.300", 7.62mm) with Gull Wing termination for PCB compatibility
• Mounting Type: Must be Surface Mount to ensure mechanical fit
• Load Voltage Range: Substitute must accommodate the required 0-400V load voltage specification
• Load Current: Substitute must support minimum 140mA load current capacity
• Input Voltage: Substitute must operate at or below 1.6VDC input specification
• On-State Resistance: Substitute performance must not exceed 27 Ohms maximum

The LH1540AAB from Vishay Semiconductor Opto Division qualifies as a functional substitute based on matching circuit configuration, package geometry, mounting type, and output type. However, the substitute exhibits reduced maximum load voltage (350V vs. 400V) and reduced load current capacity (120mA vs. 140mA), requiring application-level verification.

Parameter Comparison

Engineering Selection Recommendations

The LH1540AAB is suitable as a substitute for the HSR412S in applications where the reduced electrical ratings do not conflict with circuit requirements. The substitute component is currently in active production status, ensuring long-term availability and supply chain stability compared to the obsolete HSR412S.

The LH1540AAB demonstrates superior on-state resistance performance (20 Ohms vs. 27 Ohms maximum), which may provide thermal and efficiency benefits in switching applications. The lower input voltage requirement (1.26VDC vs. 1.6VDC) indicates improved input sensitivity.

Critical design consideration: Applications requiring the full 400V load voltage rating or 140mA load current capacity of the HSR412S must be re-evaluated against the LH1540AAB's reduced specifications (350V maximum load voltage, 120mA maximum load current). Compliance certifications (RoHS3, REACH Unaffected, EAR99) are equivalent between both components.

Frequently Asked Questions (FAQ)

Q: Can the LH1540AAB directly replace the HSR412S in all applications?

A: Direct replacement is possible only in applications where load voltage does not exceed 350V and load current does not exceed 120mA. Applications operating at the upper limits of the HSR412S specifications (400V or 140mA) require circuit redesign or alternative component selection.

Q: Are the package dimensions identical between HSR412S and LH1540AAB?

A: Yes. Both components use 6-SMD (0.300", 7.62mm) package geometry with Gull Wing termination, ensuring identical PCB footprint and reflow soldering compatibility.

Q: What is the significance of the lower on-state resistance in the LH1540AAB?

A: The LH1540AAB's maximum on-state resistance of 20 Ohms (compared to 27 Ohms for HSR412S) results in lower voltage drop across the relay during conduction, reducing power dissipation and heat generation in the switching element.

Q: Does the LH1540AAB require different input drive circuitry?

A: The LH1540AAB operates at 1.26VDC input voltage compared to the HSR412S at 1.6VDC. Existing input drive circuits designed for 1.6VDC will function with the LH1540AAB, as the substitute requires lower input voltage. However, input drive circuits must be verified to deliver sufficient current at the reduced voltage level.

Q: Are moisture sensitivity and handling requirements the same?

A: Yes. Both components are classified as MSL 1 (Unlimited), indicating no moisture sensitivity restrictions and no special storage or handling requirements.

Q: What is the availability status difference between these components?

A: The HSR412S is obsolete and no longer manufactured. The LH1540AAB is in active production status, ensuring continued availability and supply chain support for new designs and ongoing production requirements.