LNK404LG Equivalent & Substitute Parts Reference

Part Overview

The LNK404LG is an AC DC offline switcher LED driver IC manufactured by Power Integrations, designed for lighting applications requiring triac dimming capability. This LinkSwitch®-PH series component integrates an internal switch and operates across a wide input voltage range of 36V to 725V, delivering 1.02A output current in a through-hole eSIP-7F package. The part is active in production with full RoHS3 compliance and unlimited moisture sensitivity rating.

Substitute parts are identified when equivalent functional performance can be achieved within the constraints of allowed electrical parameters, package compatibility requirements, and application-specific certifications for lighting control systems.

Substiute Parts

LNK404LG

Power IntegrationsIn Stock: 1455LNK404LG Datasheet

Current PartRFQ

HV9922N8-G

Microchip TechnologyIn Stock: 25135HV9922N8-G Datasheet

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LM3447MTX/NOPB

Texas InstrumentsIn Stock: 60496LM3447MTX/NOPB Datasheet

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MP4021GS-A

Monolithic Power Systems Inc.In Stock: 1158MP4021GS-A Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the LNK404LG is determined by strict alignment of the following critical parameters:

Primary Substitution Criteria:

• Type: AC DC Offline Switcher (required match)
• Dimming Capability: Triac dimming support (required match)
• Number of Outputs: Single output configuration (required match)
• Applications: Lighting (required match)
• Topology: Flyback preferred for functional equivalence
• Voltage Supply Range: Must accommodate the operating input voltage window
• Current Output Capability: Must meet or exceed 1.02A requirement
• Internal Switch Presence: Integrated switching functionality
• Product Status: Active production status
• Compliance: RoHS and REACH certifications

Identified Substitute Parts:

1. HV9922N8-G (Microchip Technology) — Partial substitution with topology variance
2. LM3447MTX/NOPB (Texas Instruments) — Functional substitution with voltage range limitation
3. MP4021GS-A (Monolithic Power Systems Inc.) — Functional substitution with dimming capability variance

Each substitute exhibits trade-offs in electrical parameters, package form factor, or thermal specifications that must be evaluated against specific application requirements.

Parameter Comparison

Engineering Selection Recommendations

LNK404LG Primary Application Context: The LNK404LG operates as a high-voltage AC DC offline switcher with integrated internal switching, designed for direct mains input applications (36V to 725V range) with triac dimming control. The through-hole eSIP-7F package and 1.02A output current capacity define its intended use in traditional lighting fixture designs.

Substitution Feasibility Assessment:

HV9922N8-G (Microchip Technology):

• Maintains AC DC offline switcher classification and triac dimming capability
• Voltage supply range (20V to 400V) is narrower than LNK404LG, limiting high-voltage mains applications
• Output current of 50mA is significantly lower than 1.02A requirement
• Surface mount SOT-89-3 package differs from through-hole eSIP-7F form factor
• Suitable only for low-power lighting applications with modified PCB layout
• RoHS3 and unlimited MSL compliance maintained

LM3447MTX/NOPB (Texas Instruments):

• Maintains AC DC offline switcher classification with flyback topology
• Voltage supply range (7.5V to 17.5V) is substantially lower than LNK404LG, unsuitable for direct mains input
• Lacks internal switch integration (external switching required)
• Surface mount 14-TSSOP package requires PCB redesign
• Triac dimming supported; output voltage specified at 19V
• Suitable for low-voltage auxiliary power applications only
• RoHS3 and unlimited MSL compliance maintained

MP4021GS-A (Monolithic Power Systems Inc.):

• Maintains AC DC offline switcher classification with flyback topology
• Voltage supply range (10.3V to 23V) is substantially lower than LNK404LG
• Dimming capability not specified in provided parameters
• Lacks internal switch integration
• Surface mount 8-SOIC package requires PCB redesign
• MSL rating of 2 (1 Year) indicates higher moisture sensitivity than LNK404LG
• Suitable for low-voltage auxiliary power applications only
• RoHS3 and REACH compliance maintained

Recommendation Summary: Direct substitution of LNK404LG with any identified alternative part requires significant application redesign due to voltage range, current capacity, and package form factor differences. Selection of substitute parts must be driven by specific application voltage and current requirements rather than assumed functional equivalence.

Frequently Asked Questions (FAQ)

Q1: Can HV9922N8-G replace LNK404LG in a direct mains-powered lighting application?

A: No. The HV9922N8-G maximum supply voltage of 400V is insufficient for direct 725V mains input operation. Additionally, the 50mA output current is 20 times lower than the LNK404LG 1.02A specification. The surface mount SOT-89-3 package also differs from the through-hole eSIP-7F form factor, requiring PCB redesign.

Q2: What is the primary limitation of LM3447MTX/NOPB as a substitute?

A: The LM3447MTX/NOPB maximum supply voltage of 17.5V is incompatible with high-voltage mains input applications. This part is designed for low-voltage auxiliary power circuits. Additionally, it lacks an internal switch, requiring external switching circuitry. The surface mount 14-TSSOP package necessitates PCB layout modification.

Q3: Is MP4021GS-A suitable for high-current lighting applications?

A: No. The MP4021GS-A maximum supply voltage of 23V restricts its use to low-voltage auxiliary power applications. Output current is not specified in the provided parameters. The dimming capability is not documented. The surface mount 8-SOIC package differs from the through-hole eSIP-7F mounting type.

Q4: What package compatibility issues exist between LNK404LG and substitute parts?

A: LNK404LG uses a through-hole eSIP-7F package with formed leads, suitable for traditional PCB assembly. All identified substitutes (HV9922N8-G, LM3447MTX/NOPB, MP4021GS-A) are surface mount devices (SOT-89-3, 14-TSSOP, 8-SOIC respectively). Substitution requires complete PCB redesign and revalidation of thermal management.

Q5: Are all substitute parts RoHS compliant?

A: Yes. LNK404LG, HV9922N8-G, LM3447MTX/NOPB, and MP4021GS-A all carry RoHS3 compliance certification. REACH compliance status is unaffected for all parts. MSL ratings vary: LNK404LG, HV9922N8-G, and LM3447MTX/NOPB are rated MSL 1 (Unlimited); MP4021GS-A is rated MSL 2 (1 Year).

Q6: Which substitute part maintains the closest electrical parameter alignment with LNK404LG?

A: HV9922N8-G maintains the highest functional alignment in topology classification (AC DC offline switcher) and dimming capability (triac). However, significant trade-offs exist in voltage supply range (400V maximum vs. 725V) and output current (50mA vs. 1.02A). No substitute part fully matches the LNK404LG electrical specification envelope.

Q7: Can substitute parts be used in applications requiring 1.02A output current?

A: No identified substitute part meets the 1.02A output current requirement. HV9922N8-G specifies 50mA; LM3447MTX/NOPB and MP4021GS-A do not specify output current in the provided parameters. Current capacity must be independently verified against application requirements before selection.

Q8: What thermal operating range differences exist between LNK404LG and substitutes?

A: LNK404LG operates to 150°C junction temperature, the highest among all parts. HV9922N8-G is limited to 85°C ambient temperature. LM3447MTX/NOPB and MP4021GS-A operate to 125°C junction temperature. Applications requiring extended thermal operation above 125°C are incompatible with all identified substitutes.