SI-8090S Equivalent & Substitute Parts

Part Overview

The SI-8090S is a buck switching regulator IC manufactured by Sanken Electric USA Inc., designed for step-down voltage conversion applications. This device delivers a fixed 9V output at 3A from input voltages ranging from 12V to 40V, housed in a TO-220-5 package with formed leads. The product is currently obsolete, making identification of compatible substitute components essential for ongoing system support, maintenance, and new design implementations where fixed 9V regulation is required.

Substiute Parts

SI-8090S

Sanken Electric USA Inc.In Stock: 1065SI-8090S Datasheet

Current PartRFQ

BD9702T-V5

Rohm SemiconductorIn Stock: 17182BD9702T-V5 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the SI-8090S is determined by the following critical parameters:

Electrical Compatibility Requirements:

• Output voltage capability: Must support fixed 9V output or adjustable output with 9V within operating range
• Output current rating: Minimum 3A continuous capability
• Input voltage tolerance: Must accept 12V to 40V input range
• Topology: Buck (step-down) switching regulator
• Package: TO-220-5 Full Pack, Formed Leads (through-hole mounting)

Mechanical & Environmental Compatibility:

• Identical or compatible package footprint (TO-220-5)
• Operating temperature range must cover or exceed -30°C to 125°C where feasible
• Synchronous rectifier configuration: Non-synchronous preferred for direct replacement

The BD9702T-V5 qualifies as a substitute because it maintains the same package format, supports 3A output current, accepts the required input voltage range, and provides adjustable output capability that includes the 9V fixed voltage requirement through external resistor configuration.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement in Active Systems:

The BD9702T-V5 serves as the primary substitute for the obsolete SI-8090S. Both devices share identical package geometry (TO-220-5), output current rating (3A), and non-synchronous rectifier architecture. The BD9702T-V5 is currently in active production status with substantial inventory availability (17,100 pcs), ensuring long-term supply continuity.

Key Considerations for Implementation:

The BD9702T-V5 requires external resistor network configuration to establish the 9V fixed output voltage, whereas the SI-8090S provides factory-set 9V output. Design integration requires addition of feedback resistors per Rohm Semiconductor datasheets to achieve equivalent voltage regulation. The BD9702T-V5 operates at 110kHz switching frequency compared to the SI-8090S 60kHz specification, resulting in reduced output filter component size but requiring verification of EMI performance in the target application.

Input voltage range differences exist: the BD9702T-V5 accepts 8V minimum (lower than SI-8090S 12V minimum) but maximum input is 35V (lower than SI-8090S 40V maximum). System designs operating above 35V input require alternative solutions.

Operating temperature specification differs: the BD9702T-V5 ambient temperature range (-40°C to 85°C TA) is narrower than the SI-8090S junction temperature range (-30°C to 125°C TJ). Applications requiring operation above 85°C ambient require thermal analysis and potential derating.

Both devices maintain RoHS compliance (RoHS3 for BD9702T-V5) and identical MSL ratings, supporting environmental and regulatory requirements.

Frequently Asked Questions (FAQ)

Q: Can the BD9702T-V5 directly replace the SI-8090S without circuit modifications?

A: Physical and electrical pin compatibility exists due to identical TO-220-5 package format and 3A output current rating. However, the BD9702T-V5 requires external resistor configuration to set output voltage to 9V, whereas the SI-8090S provides fixed 9V output. Circuit board modifications are necessary to add feedback resistors per the BD9702T-V5 datasheet.

Q: What are the input voltage limitations when substituting?

A: The SI-8090S accepts 12V to 40V input. The BD9702T-V5 accepts 8V to 35V input. Systems designed for SI-8090S operation at input voltages between 35V and 40V cannot use the BD9702T-V5 without alternative regulation solutions.

Q: How does the higher switching frequency of the BD9702T-V5 affect system design?

A: The BD9702T-V5 operates at 110kHz versus the SI-8090S 60kHz. Higher switching frequency permits smaller output filter inductors and capacitors, reducing board space. However, EMI characteristics may differ; verification through conducted and radiated emissions testing is necessary for applications with strict EMI requirements.

Q: Are there temperature rating concerns for high-temperature applications?

A: The SI-8090S specifies -30°C to 125°C junction temperature operation. The BD9702T-V5 specifies -40°C to 85°C ambient temperature operation. Applications requiring sustained operation above 85°C ambient require thermal modeling to confirm the BD9702T-V5 junction temperature remains within limits, or alternative components must be selected.

Q: What is the inventory status for long-term supply?

A: The SI-8090S is obsolete with 993 pcs remaining in stock. The BD9702T-V5 is in active production status with 17,100 pcs available, ensuring supply continuity for new designs and system maintenance.

Q: Are both devices RoHS compliant?

A: Yes. The SI-8090S is RoHS Compliant. The BD9702T-V5 is ROHS3 Compliant. Both meet current environmental regulations for lead-free manufacturing and hazardous substance restrictions.