CS1611-FSZR LED Driver IC Equivalent & Substitute Parts

Part Overview

The CS1611-FSZR is an LED driver IC manufactured by Cirrus Logic Inc., designed for offline AC/DC switching applications with flyback and step-up (boost) topology. This component features triac dimming capability and is rated for lighting applications across an operating temperature range of -40°C to 125°C. The part is currently classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and production continuity.

Substiute Parts

CS1611-FSZR

Cirrus Logic Inc.In Stock: 45050CS1611-FSZR Datasheet

Current PartRFQ

LM3450AMTX/NOPB

Texas InstrumentsIn Stock: 3119LM3450AMTX/NOPB Datasheet

MFR RecommendedRFQ

MP4000DS-LF

Monolithic Power Systems Inc.In Stock: 1316MP4000DS-LF Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the CS1611-FSZR are identified based on the following core compatibility criteria:

• Functional Category: AC DC offline switcher for LED driver applications
• Topology Compatibility: Flyback or step-up (boost) converter architecture
• Single Output Configuration: One output channel
• Voltage Supply Overlap: Supply voltage range must accommodate the 11V to 17V requirement
• Dimming Capability: Support for triac or analog dimming methods
• Package Compatibility: Surface mount packages suitable for PCB integration
• Operating Temperature Range: Support for -40°C to 125°C operation
• Product Availability: Active or in-stock status for production use

The identified substitutes meet these criteria with variations in specific parameters such as package type, internal switch configuration, and dimming method, which are acceptable within the functional requirements of offline LED driver applications.

Parameter Comparison

Engineering Selection Recommendations

LM3450AMTX/NOPB (Texas Instruments)

This part is classified as active with full production availability. It maintains the same AC DC offline switcher topology with flyback and step-up (boost) capability as the CS1611-FSZR. The supply voltage range (8.5V to 20V) encompasses the original 11V to 17V requirement. The LM3450AMTX/NOPB includes an internal switch, which differs from the original design but provides functional equivalence for offline LED driver applications. It supports analog dimming rather than triac dimming. The part is ROHS3 compliant with superior moisture sensitivity rating (MSL 1). The 16-TSSOP package requires PCB layout adjustment from the original 16-SOIC footprint.

MP4000DS-LF (Monolithic Power Systems Inc.)

This part is classified as active with current production status. It functions as an AC DC offline switcher but employs step-down (buck) topology rather than the original flyback/boost configuration. The supply voltage range (8V to 10.5V) does not fully encompass the original 11V to 17V specification, with the maximum rating at 10.5V falling below the original minimum of 11V. This part supports analog and PWM dimming methods. It is ROHS3 compliant with MSL 2 rating. The 8-SOIC package represents a significant reduction in pin count and physical footprint. The operating temperature maximum is limited to 85°C (TA) compared to the original 125°C (TJ). This part is designated as automotive grade.

Frequently Asked Questions (FAQ)

Q: Why is the CS1611-FSZR classified as obsolete?

A: The CS1611-FSZR is no longer in active production by Cirrus Logic Inc. Identifying substitute parts ensures design continuity and production support for applications currently using this component.

Q: Can the LM3450AMTX/NOPB directly replace the CS1611-FSZR?

A: The LM3450AMTX/NOPB provides functional equivalence as an AC DC offline switcher with flyback and step-up topology for LED driver applications. However, the package differs (16-TSSOP vs. 16-SOIC), requiring PCB layout modification. The dimming method differs (analog vs. triac), which may require circuit design adjustment depending on the application's dimming control requirements.

Q: What are the key differences between the LM3450AMTX/NOPB and MP4000DS-LF?

A: The LM3450AMTX/NOPB maintains flyback/boost topology matching the original part, while the MP4000DS-LF uses step-down (buck) topology. The LM3450AMTX/NOPB supply voltage range (8.5V to 20V) fully covers the original specification, whereas the MP4000DS-LF maximum supply voltage (10.5V) falls below the original minimum requirement of 11V. Package sizes also differ significantly (16-TSSOP vs. 8-SOIC).

Q: Is the MP4000DS-LF suitable for applications requiring the full 11V to 17V supply range?

A: No. The MP4000DS-LF maximum supply voltage rating of 10.5V does not meet the original specification minimum of 11V. This part is not recommended for applications requiring operation at or above 11V supply voltage.

Q: What packaging considerations apply when selecting a substitute?

A: The CS1611-FSZR uses 16-SOIC packaging. The LM3450AMTX/NOPB uses 16-TSSOP, which has different pin spacing and footprint dimensions (0.173" vs. 0.154" width). The MP4000DS-LF uses 8-SOIC, representing a different pin count entirely. PCB layout and schematic modifications are required for either substitute.

Q: Are both substitute parts RoHS compliant?

A: Yes. Both the LM3450AMTX/NOPB and MP4000DS-LF are ROHS3 compliant. The original CS1611-FSZR RoHS status is not specified in the available documentation.

Q: How do the operating temperature ranges compare?

A: The CS1611-FSZR and LM3450AMTX/NOPB both support -40°C to 125°C (junction temperature). The MP4000DS-LF is limited to -40°C to 85°C (ambient temperature), which may be insufficient for applications requiring the full 125°C thermal performance of the original part.