PS7122L-1A Solid State Relay SPST-NO Equivalent & Substitute Parts

Part Overview

The PS7122L-1A is a solid state relay (SSR) manufactured by CEL, configured as a single-pole single-throw normally open (SPST-NO) device rated for 200 mA load current at 0–200 V AC/DC output. The device features a 1.2 VDC input trigger voltage and surface mount 6-SMD gull wing termination. This part is classified as obsolete, necessitating identification of functionally equivalent alternatives for ongoing design support and procurement continuity.

Substiute Parts

PS7122L-1A

CELIn Stock: 2989PS7122L-1A Datasheet

Current PartRFQ

AQV217A

Panasonic Electric WorksIn Stock: 3277AQV217A Datasheet

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AQV257A

Panasonic Electric WorksIn Stock: 1755AQV257A Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the PS7122L-1A is determined by strict equivalence across the following electrical and mechanical parameters:

Critical Substitution Criteria:

• Circuit configuration: SPST-NO (1 Form A) only
• Output type: AC and DC capability required
• Load voltage range: 0 V ~ 200 V minimum
• Package / Case: 6-SMD (0.300", 7.62mm) form factor
• Termination style: Gull Wing
• Mounting type: Surface Mount

Load Current Consideration: The PS7122L-1A specifies 200 mA maximum load current. Substitute parts must support this current rating or higher to maintain functional equivalence. Parts rated below 200 mA are not suitable replacements.

Input Voltage Tolerance: The PS7122L-1A requires 1.2 VDC input trigger. Substitute parts with input voltages within the same logic family (1.14 VDC to 1.2 VDC range) are acceptable for direct substitution.

Two substitute parts meet these criteria: AQV217A (180 mA) and AQV257A (250 mA). The AQV217A operates below the 200 mA specification and is therefore not a direct equivalent. The AQV257A meets all substitution criteria with 250 mA capacity, exceeding the original specification.

Parameter Comparison

Engineering Selection Recommendations

AQV257A - Recommended Substitute:

The AQV257A is the primary equivalent for the PS7122L-1A. This Panasonic PhotoMOS™ AQV series device meets all substitution criteria: identical circuit configuration (SPST-NO), matching load voltage range (0–200 V), and superior load current rating (250 mA vs. 200 mA). The AQV257A exhibits lower on-state resistance (4 Ohms vs. 5 Ohms), providing improved electrical performance. The device is active in production status with ROHS3 compliance, ensuring long-term availability and regulatory alignment. Input voltage (1.14 VDC) is compatible within standard logic levels.

AQV217A - Limited Substitution:

The AQV217A does not meet the load current specification of the PS7122L-1A. With a maximum rating of 180 mA, this device falls below the original 200 mA requirement and is unsuitable for direct replacement in applications requiring the full 200 mA capacity. The AQV217A may be considered only in applications where actual load current does not exceed 180 mA. Higher on-state resistance (15 Ohms vs. 5 Ohms) also represents a performance degradation.

Compliance Considerations:

Both substitute parts are ROHS3 compliant and REACH unaffected, addressing regulatory requirements absent in the obsolete PS7122L-1A. Designs transitioning from PS7122L-1A should prioritize AQV257A to maintain electrical specifications and gain compliance benefits.

Frequently Asked Questions (FAQ)

Q: Can the AQV217A replace the PS7122L-1A in all applications?

A: No. The AQV217A is rated for 180 mA maximum load current, which is below the PS7122L-1A specification of 200 mA. Substitution is only valid if the actual application load current does not exceed 180 mA. For applications requiring the full 200 mA capacity, use AQV257A.

Q: Are the input voltage differences between PS7122L-1A (1.2 VDC) and the substitute parts (1.14 VDC) significant?

A: No. The 0.06 VDC difference falls within standard logic level tolerances and does not affect functional compatibility. Both input voltages operate within the same control circuit family.

Q: Do the substitute parts have identical package dimensions?

A: Yes. Both AQV217A and AQV257A use the 6-SMD (0.300", 7.62mm) package with gull wing termination, matching the PS7122L-1A footprint exactly. PCB layout and assembly processes require no modification.

Q: What is the significance of the on-state resistance difference?

A: On-state resistance affects voltage drop across the relay during conduction. The PS7122L-1A specifies 5 Ohms maximum. AQV257A (4 Ohms) provides lower resistance and reduced power dissipation. AQV217A (15 Ohms) exhibits higher resistance, increasing heat generation and voltage drop. For thermal-sensitive applications, AQV257A is preferred.

Q: Why is AQV257A preferred over AQV217A despite both being Panasonic PhotoMOS™ devices?

A: AQV257A meets or exceeds all electrical specifications of the PS7122L-1A (250 mA vs. 200 mA load current, 4 Ohms vs. 5 Ohms on-state resistance), ensuring direct functional equivalence. AQV217A falls short on load current capacity (180 mA), limiting its application scope. AQV257A is the only true substitute.

Q: Are there any compliance advantages to using the substitute parts?

A: Yes. Both AQV217A and AQV257A are ROHS3 compliant and REACH unaffected, whereas the PS7122L-1A is RoHS non-compliant. Designs using substitute parts automatically meet modern regulatory requirements without additional design changes.

Q: Can these relays be used interchangeably in existing PCB designs?

A: Yes, for the AQV257A. The identical 6-SMD gull wing package allows direct PCB substitution without layout modifications. Electrical parameters are compatible with PS7122L-1A designs. For AQV217A, substitution is only valid if load current specifications permit the lower 180 mA rating.