CS1611-FSZ Equivalent & Substitute Parts

Part Overview

The CS1611-FSZ is an LED driver IC manufactured by Cirrus Logic Inc., designed for AC/DC offline switching applications with Flyback and Step-Up (Boost) topologies. This 16-SOIC surface mount device features Triac dimming capability and operates across a supply voltage range of 11V to 17V, making it suitable for lighting applications requiring offline power conversion.

The CS1611-FSZ is classified as obsolete. Due to its discontinued status, identifying functionally equivalent substitute parts is essential for maintaining design continuity, ensuring supply chain reliability, and supporting long-term product availability in lighting applications.

Substiute Parts

CS1611-FSZ

Cirrus Logic Inc.In Stock: 2536CS1611-FSZ Datasheet

Current PartRFQ

LM3450AMT/NOPB

Texas InstrumentsIn Stock: 1255LM3450AMT/NOPB Datasheet

MFR RecommendedRFQ

MP4050AGS-Z

Monolithic Power Systems Inc.In Stock: 3895MP4050AGS-Z Datasheet

MFR RecommendedRFQ

TC62D902FG,C,8,EL

Toshiba Semiconductor and StorageIn Stock: 870TC62D902FG,C,8,EL Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the CS1611-FSZ are identified based on the following critical parameters that determine functional equivalence:

Primary Substitution Criteria:

• AC/DC offline switcher topology with single output
• Triac dimming capability (preferred for direct replacement)
• Operating temperature range of -40°C to 125°C
• Surface mount packaging suitable for lighting applications
• Supply voltage compatibility within or overlapping the 11V–17V range

Secondary Considerations:

• Internal switch presence (CS1611-FSZ has no internal switch; substitutes may vary)
• Specific topology variant (Flyback, Step-Up/Boost, or Step-Down/Buck)
• Package form factor and pin count
• Product status (active status preferred for long-term availability)

The three identified substitutes represent different topology approaches while maintaining core offline switching and dimming functionality required for LED driver applications.

Parameter Comparison

Engineering Selection Recommendations

LM3450AMT/NOPB (Texas Instruments)

This part offers the closest functional alignment to the CS1611-FSZ, sharing identical Flyback and Step-Up (Boost) topology and matching operating temperature range (-40°C to 125°C). The supply voltage range (8.5V–20V) encompasses the original 11V–17V specification. The LM3450AMT/NOPB features an internal switch and analog dimming rather than Triac dimming, requiring circuit design modifications if Triac dimming is mandatory. Active product status and ROHS3 compliance ensure long-term availability. The 16-TSSOP package differs from the original 16-SOIC, necessitating PCB layout adjustments. MSL 1 rating provides superior moisture handling compared to the original MSL 3.

TC62D902FG,C,8,EL (Toshiba Semiconductor and Storage)

This substitute maintains Triac dimming capability and Flyback topology, directly addressing the dimming requirement of the original design. Supply voltage range (1.8V–25V) exceeds the original specification, providing design flexibility. The part operates at 200kHz switching frequency and includes a 15V output specification. Operating temperature range is -40°C to 85°C (TA), which is narrower than the original -40°C to 125°C (TJ) specification. The 8-SOIC package is significantly smaller than the original 16-SOIC, reducing board space but requiring careful PCB redesign. Active product status and ROHS3 compliance support supply chain continuity. MSL 1 rating provides superior moisture protection.

MP4050AGS-Z (Monolithic Power Systems Inc.)

This part represents a topology departure, employing Step-Down (Buck) conversion instead of Flyback or Boost topologies. Supply voltage range (4.1V–5V) is substantially lower than the original 11V–17V specification, limiting direct substitution applicability. The part lacks Triac dimming capability. The 8-SOIC package reduces board footprint. Active product status, ROHS3 compliance, and automotive-grade qualification support reliability in demanding environments. Switching frequency of 22kHz differs from typical offline switcher designs. This substitute is suitable only for applications where topology and voltage requirements can be redesigned.

Frequently Asked Questions (FAQ)

Q: Can the LM3450AMT/NOPB directly replace the CS1611-FSZ without circuit modifications?

A: The LM3450AMT/NOPB shares topology and temperature range but differs in dimming method (analog vs. Triac) and package form factor (16-TSSOP vs. 16-SOIC). Circuit modifications are required to accommodate analog dimming control and PCB layout changes for the different package.

Q: Why is the TC62D902FG,C,8,EL recommended despite its narrower operating temperature range?

A: The TC62D902FG,C,8,EL preserves Triac dimming functionality and Flyback topology, maintaining design compatibility for dimming circuits. The -40°C to 85°C (TA) range is suitable for most lighting applications. If the full -40°C to 125°C (TJ) range is critical, the LM3450AMT/NOPB is preferred despite its analog dimming requirement.

Q: What are the package compatibility implications?

A: The CS1611-FSZ uses 16-SOIC packaging. The LM3450AMT/NOPB uses 16-TSSOP (similar pin count, different footprint), while TC62D902FG,C,8,EL and MP4050AGS-Z use 8-SOIC (reduced pin count). Package changes require PCB redesign and potential schematic modifications to accommodate different pin configurations.

Q: Is the MP4050AGS-Z suitable for direct substitution?

A: The MP4050AGS-Z is not recommended for direct substitution due to its Step-Down (Buck) topology, which differs fundamentally from the original Flyback/Boost design. Its 4.1V–5V supply voltage range is incompatible with the original 11V–17V specification. This part is suitable only for applications where the power conversion architecture can be redesigned.

Q: What compliance advantages do the substitute parts offer?

A: All three substitutes carry ROHS3 compliance, compared to the original part's unspecified RoHS status. The LM3450AMT/NOPB and TC62D902FG,C,8,EL feature MSL 1 ratings (unlimited moisture exposure), providing superior handling compared to the original MSL 3 (168 hours). These improvements support modern manufacturing and storage requirements.

Q: Which substitute is recommended for new designs?

A: For new designs requiring Triac dimming and Flyback topology, the TC62D902FG,C,8,EL is recommended. For designs where analog dimming is acceptable, the LM3450AMT/NOPB offers superior compliance and moisture protection. Both are active products with established supply chains.