LNK6404D Equivalent & Substitute Parts

Part Overview

The LNK6404D is an offline switch flyback converter IC manufactured by Power Integrations, designed for isolated power supply applications. This device integrates a high-voltage internal switch with comprehensive fault protection in a compact 8-SOIC package. The LNK6404D is discontinued at DiGi Electronics, necessitating identification of functionally equivalent alternatives for ongoing design support and production requirements.

Substiute Parts

LNK6404D

Power IntegrationsIn Stock: 1327LNK6404D Datasheet

Current PartRFQ

LNK6417D

Power IntegrationsIn Stock: 8605LNK6417D Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

The LNK6417D qualifies as a parametric equivalent to the LNK6404D based on the following substitution criteria:

Matching Parameters (Substitution Basis):

• Identical manufacturer: Power Integrations
• Same series: LinkSwitch™-3
• Identical topology: Flyback converter
• Identical output isolation: Isolated
• Identical voltage breakdown rating: 725V
• Identical switching frequency: Up to 85kHz
• Identical duty cycle: 55%
• Identical operating temperature range: -40°C ~ 150°C (TJ)
• Identical package type: 8-SOIC (0.154", 3.90mm Width), 7 Leads
• Identical mounting type: Surface Mount
• Identical fault protection features: Current Limiting, Open Loop, Over Temperature, Short Circuit
• Identical compliance: RoHS Compliant, MSL 1

Differing Parameter:

• Power rating: LNK6404D rated at 4.1 W; LNK6417D rated at 7.5 W

The LNK6417D operates at a higher power level while maintaining all other electrical and mechanical specifications. This difference permits substitution in applications where the LNK6404D's 4.1 W rating is sufficient, as the higher-rated device operates within the same electrical envelope.

Parameter Comparison

Engineering Selection Recommendations

The LNK6417D is a direct substitute for the LNK6404D in applications where the original device is no longer available. Both devices are RoHS Compliant and carry identical MSL ratings, ensuring compliance with environmental and reliability standards.

The primary distinction is the power rating differential: the LNK6417D provides 7.5 W capability compared to the LNK6404D's 4.1 W. This higher rating does not create incompatibility; rather, it expands the operational envelope. The LNK6417D maintains identical electrical characteristics across all other parameters, including breakdown voltage, switching frequency, duty cycle, temperature range, and fault protection mechanisms.

For designs currently operating the LNK6404D at or below 4.1 W, direct substitution with the LNK6417D is permissible without circuit modification. The identical package footprint (8-SOIC, 7 Leads) and mounting type (Surface Mount) ensure mechanical compatibility on existing PCBs.

Frequently Asked Questions (FAQ)

Q: Can the LNK6417D replace the LNK6404D in existing designs?

A: Yes. The LNK6417D is mechanically and electrically compatible with the LNK6404D. Both devices share identical package specifications (8-SOIC, 7 Leads), mounting type (Surface Mount), and all critical electrical parameters including topology, voltage rating, switching frequency, and fault protection features. No PCB redesign is required.

Q: What is the primary difference between these two parts?

A: The LNK6417D is rated for 7.5 W output power, while the LNK6404D is rated for 4.1 W. All other specifications remain identical. This difference does not affect substitution compatibility for applications operating within the LNK6404D's original power specification.

Q: Are there any compliance or certification differences?

A: No. Both the LNK6404D and LNK6417D carry identical RoHS Compliance status and MSL ratings (1 - Unlimited). They meet the same environmental and reliability standards.

Q: Will the LNK6417D fit the same PCB footprint?

A: Yes. Both devices use the 8-SOIC package with 0.154" (3.90mm) width and 7 leads. The physical footprint is identical, permitting direct PCB placement without modification.

Q: Are both devices still in production?

A: The LNK6404D is discontinued at DiGi Electronics. The LNK6417D remains available with higher inventory levels (8563 Pcs in stock versus 1300 Pcs for the LNK6404D), making it the recommended choice for new procurement.

Q: What fault protection features do these devices include?

A: Both the LNK6404D and LNK6417D incorporate identical fault protection: Current Limiting, Open Loop, Over Temperature, and Short Circuit protection.

Q: Is the operating temperature range the same?

A: Yes. Both devices operate across the identical temperature range of -40°C to 150°C (junction temperature), ensuring thermal compatibility in equivalent applications.