STR-Y6766 Equivalent & Substitute Parts

Part Overview

The STR-Y6766 is an offline switching flyback converter IC manufactured by Sanken Electric USA Inc., designed for isolated power supply applications. This component operates in the 18.4kHz to 24.4kHz frequency range with a maximum power rating of 140W and an 800V breakdown voltage. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The STR-Y6766 is housed in a TO-220F-7 package with through-hole mounting and includes integrated fault protection for current limiting, overload, over-temperature, and over-voltage conditions.

Substiute Parts

STR-Y6766

Sanken Electric USA Inc.In Stock: 11812STR-Y6766 Datasheet

Current PartRFQ

STR-Y6765

Sanken Electric USA Inc.In Stock: 3215STR-Y6765 Datasheet

Parametric EquivalentRFQ

TOP257YN

Power IntegrationsIn Stock: 16922TOP257YN Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the STR-Y6766 is determined by the following critical parameters: isolated flyback topology, TO-220-7 package compatibility, through-hole mounting, 800V or higher breakdown voltage rating, and fault protection features including current limiting, over-temperature, and over-voltage protection.

The STR-Y6765 is classified as a parametric equivalent within the same STR-Y6700 series. It maintains identical topology, package, mounting type, and protection features. The primary difference is a reduced power rating of 120W compared to the STR-Y6766's 140W, making it suitable for lower-power applications within the same design envelope.

The TOP257YN is classified as a similar substitute from Power Integrations' TOPSwitch-HX series. While it shares the same isolated flyback topology, TO-220-7 package, and through-hole mounting, it operates at a higher switching frequency (66kHz, 132kHz) and has a lower breakdown voltage (700V). This part is suitable for designs where higher frequency operation is acceptable and the 700V rating meets application requirements.

Parameter Comparison

Engineering Selection Recommendations

For designs currently using the STR-Y6766, the STR-Y6765 provides the most direct substitution path within the same manufacturer's product line. Both parts share identical electrical specifications except for power rating, maintain the same operating frequency range, and are housed in compatible packages. However, both parts carry obsolete status, limiting long-term availability.

The TOP257YN from Power Integrations represents an active product with ongoing manufacturing support. This part is suitable for applications where the 700V breakdown voltage meets system requirements and where higher switching frequency operation (66kHz, 132kHz) is compatible with the power supply design. The TOP257YN offers superior thermal operating range (-40°C to 150°C junction temperature) compared to the STR-Y6766's -20°C to 115°C ambient temperature range. All three parts maintain RoHS compliance and equivalent moisture sensitivity ratings.

Frequently Asked Questions (FAQ)

Q: Can the STR-Y6765 directly replace the STR-Y6766 in existing designs?

A: The STR-Y6765 is electrically compatible for applications requiring 120W or less. Both parts operate at identical switching frequencies (18.4kHz ~ 24.4kHz), share the same supply voltage range (9.4V ~ 35V), and are housed in compatible TO-220-7 packages. Designs operating at the full 140W rating of the STR-Y6766 require thermal and power budget reassessment with the STR-Y6765.

Q: What are the key differences between the STR-Y6766 and TOP257YN?

A: The primary differences are switching frequency and breakdown voltage. The STR-Y6766 operates at 18.4kHz ~ 24.4kHz with 800V breakdown voltage, while the TOP257YN operates at 66kHz or 132kHz with 700V breakdown voltage. The TOP257YN has higher power capability (157W) and extended operating temperature range. Substitution requires verification that the higher switching frequency does not introduce EMI or control loop stability issues in the target application.

Q: Are all three parts housed in the same package?

A: All three parts use TO-220-7 formed leads packages with through-hole mounting. The TOP257YN is specified as TO-220-7C with 6 leads, while the STR-Y6766 and STR-Y6765 use TO-220F-7 packages. Physical compatibility should be verified against PCB layout and thermal management requirements.

Q: What is the impact of the STR-Y6766 and STR-Y6765 being obsolete?

A: Obsolete status indicates these parts are no longer in active production. Existing inventory may be available through authorized distributors, but long-term supply cannot be guaranteed. For new designs or production continuity beyond current inventory, the active TOP257YN part from Power Integrations is the recommended path forward.

Q: Do all substitute parts include the same fault protection features?

A: The STR-Y6766 and STR-Y6765 include current limiting, overload, over-temperature, and over-voltage protection. The TOP257YN includes current limiting, over-temperature, and over-voltage protection but does not specify overload protection. Application-specific protection requirements should be evaluated when selecting between these parts.