FL77904MX LED Driver IC - Equivalent & Substitute Parts

Part Overview

The FL77904MX is an AC/DC offline switcher LED driver IC manufactured by onsemi, designed for lighting applications requiring triac dimming capability. This device integrates an internal switch and supports four output channels with selectable current outputs (28.6mA, 53.6mA, 93.8mA, 104.2mA). The part operates from 90VAC to 305VAC input and delivers 18V output.

The FL77904MX is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for lighting systems utilizing this topology.

Substiute Parts

FL77904MX

onsemiIn Stock: 1276FL77904MX Datasheet

Current PartRFQ

NCL30170ADR2G

onsemiIn Stock: 35347NCL30170ADR2G Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the FL77904MX requires evaluation against the following critical parameters that define functional equivalence:

Primary Substitution Criteria:

• Topology: AC/DC offline switcher capability with internal switching functionality
• Input voltage range: Support for 90VAC to 305VAC operation
• Output configuration: Multi-channel LED driver with selectable current outputs
• Dimming control: Triac-compatible dimming interface
• Thermal performance: Operating temperature range of -40°C to 125°C
• Compliance: ROHS3 compliance and MSL rating compatibility

The NCL30170ADR2G is identified as a substitute part from onsemi. However, this part operates as a linear analog LED driver with fundamentally different topology, input voltage requirements (9V to 20.5V DC), and dimming methodology (analog vs. triac). While both devices are LED driver ICs from the same manufacturer with identical thermal and compliance specifications, the NCL30170ADR2G requires external DC power supply and analog control circuitry, making it suitable only for applications where the AC/DC offline switcher topology is not required.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Same Application): No direct pin-compatible or functionally equivalent substitute is available from the provided data. The FL77904MX is an obsolete AC/DC offline switcher with triac dimming, and the NCL30170ADR2G is a linear analog driver requiring external DC power supply. These represent different architectural approaches to LED driver design.

For New Designs or Redesigns: If the FL77904MX is no longer available and direct replacement is not feasible, design migration to the NCL30170ADR2G requires:

• Addition of external AC/DC power supply stage to convert 90VAC-305VAC to 9V-20.5V DC
• Replacement of triac dimming interface with analog voltage control circuitry
• Redesign of output channel configuration from 4 channels to single-channel operation
• Potential addition of external current-limiting resistors or additional driver stages for multi-channel applications

Both parts maintain identical operating temperature ranges (-40°C to 125°C), ROHS3 compliance, and MSL ratings, ensuring environmental and regulatory compatibility.

Frequently Asked Questions (FAQ)

Q: Can the NCL30170ADR2G be used as a direct replacement for the FL77904MX? A: No. The NCL30170ADR2G is not a direct replacement. It requires DC power input (9V-20.5V), uses analog dimming control instead of triac dimming, and provides single-channel output instead of four channels. Circuit redesign is necessary for substitution.

Q: What is the primary difference between these two LED driver ICs? A: The FL77904MX is an AC/DC offline switcher that directly converts AC mains voltage (90VAC-305VAC) to a regulated 18V output with integrated triac dimming. The NCL30170ADR2G is a linear analog driver that requires pre-regulated DC input (9V-20.5V) and uses analog voltage control for dimming. They serve different system architectures.

Q: Are both parts compliant with current environmental regulations? A: Yes. Both the FL77904MX and NCL30170ADR2G are ROHS3 compliant and carry identical MSL ratings (3, 168 Hours), meeting current environmental and moisture sensitivity requirements.

Q: What are the package differences? A: The FL77904MX uses an 8-SOIC package with exposed pad, while the NCL30170ADR2G uses a 10-SOP package. Both maintain the same 0.154" (3.90mm) width, but the NCL30170ADR2G has two additional pins. PCB layout redesign is required for substitution.

Q: Is the NCL30170ADR2G available in higher quantities? A: Yes. The NCL30170ADR2G is in active production status with 35,300 pieces in stock, compared to the obsolete FL77904MX with 1,230 pieces remaining. This makes the NCL30170ADR2G suitable for new production commitments.

Q: Can multiple NCL30170ADR2G devices be paralleled to achieve four-channel output? A: Theoretically possible, but requires external analog control distribution circuitry and careful current-sharing design. This approach increases component count, PCB area, and design complexity compared to the integrated four-channel FL77904MX architecture.