SI-8150S Equivalent & Substitute Parts

Part Overview

The SI-8150S is a buck switching regulator IC manufactured by Sanken Electric USA Inc., designed for step-down voltage conversion applications. It delivers a fixed 15V output at 3A from an input range of 18V to 40V, operating at 60kHz switching frequency in a TO-220-5 package with formed leads. The device is classified as obsolete, making identification of suitable substitute components essential for ongoing system support and new design implementations.

Substiute Parts

SI-8150S

Sanken Electric USA Inc.In Stock: 2843SI-8150S Datasheet

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BD9702T-V5

Rohm SemiconductorIn Stock: 17182BD9702T-V5 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the SI-8150S requires evaluation based on the following critical parameters:

Topology & Function: Both the main part and substitute must operate as buck (step-down) switching regulators with positive output configuration.

Package Compatibility: The TO-220-5 Full Pack, Formed Leads package is a primary constraint. Substitute parts must use identical or pin-compatible packaging to ensure direct board-level replacement without layout modifications.

Output Current Rating: The 3A output current capability must be maintained or exceeded in the substitute to support the same load requirements.

Input Voltage Range: The substitute must accept the system input voltage range. The SI-8150S operates from 18V to 40V; substitutes must cover this range or be verified for compatibility within the specific application.

Output Voltage: The SI-8150S provides a fixed 15V output. Substitutes with adjustable output capability can be used if configured to 15V, provided the adjustment range includes this voltage.

Electrical Characteristics: Switching frequency, synchronous rectification capability, and thermal operating range should be evaluated for system-level performance impact.

The BD9702T-V5 meets these substitution criteria through compatible packaging, matching current rating, overlapping input voltage range, and adjustable output capability that includes the required 15V setting.

Parameter Comparison

Engineering Selection Recommendations

BD9702T-V5 as Primary Substitute:

The BD9702T-V5 is an active product from Rohm Semiconductor with ROHS3 compliance, providing long-term availability and supply chain stability compared to the obsolete SI-8150S. Both devices share identical TO-220-5 packaging and 3A output current capability, enabling direct board-level substitution.

The BD9702T-V5 features an adjustable output voltage range (1V to 32V) that encompasses the required 15V fixed output of the SI-8150S. External resistor dividers must be configured to set the output to 15V; this requires design modification but does not impact physical compatibility or thermal performance.

Input voltage range differences exist: the SI-8150S operates from 18V to 40V, while the BD9702T-V5 operates from 8V to 35V. The overlap range of 18V to 35V is suitable for applications within the original SI-8150S specification. Applications requiring operation above 35V input voltage cannot use the BD9702T-V5 without additional input conditioning.

Operating temperature ranges differ: the SI-8150S is rated to 125°C junction temperature, while the BD9702T-V5 is rated to 85°C ambient temperature. Thermal analysis is required for high-temperature applications to confirm the BD9702T-V5 remains within safe operating limits.

Both devices are RoHS compliant and carry identical ECCN and HTSUS classifications, supporting regulatory and export compliance requirements.

Frequently Asked Questions (FAQ)

Q: Can the BD9702T-V5 directly replace the SI-8150S without circuit modifications?

A: Physical and electrical compatibility is supported through identical TO-220-5 packaging and matching 3A output current. However, the BD9702T-V5 requires external resistor configuration to set the output voltage to 15V, whereas the SI-8150S provides fixed 15V output. Circuit design modifications are necessary to implement the feedback network for voltage adjustment.

Q: What is the input voltage compatibility between these devices?

A: The SI-8150S operates from 18V to 40V input. The BD9702T-V5 operates from 8V to 35V input. The overlapping range is 18V to 35V. Applications requiring input voltages above 35V cannot use the BD9702T-V5 without additional input voltage regulation or conditioning.

Q: Are there thermal performance differences?

A: The SI-8150S is rated to -30°C to 125°C (junction temperature), while the BD9702T-V5 is rated to -40°C to 85°C (ambient temperature). The BD9702T-V5 has a lower maximum operating temperature. Thermal modeling is required for applications operating near or above 85°C ambient to ensure the device remains within safe limits.

Q: What switching frequency differences exist, and do they impact system design?

A: The SI-8150S operates at 60kHz switching frequency, while the BD9702T-V5 operates at 110kHz. The higher switching frequency of the BD9702T-V5 may reduce output filter component sizes but could introduce different EMI characteristics. System-level EMI testing is recommended when substituting.

Q: Are both devices RoHS compliant?

A: Yes. The SI-8150S is RoHS Compliant, and the BD9702T-V5 is ROHS3 Compliant. Both meet current RoHS requirements for new designs and ongoing production.

Q: What is the product status difference, and why does it matter?

A: The SI-8150S is classified as obsolete, indicating discontinued production and limited future availability. The BD9702T-V5 is active, ensuring ongoing manufacturing, supply chain availability, and technical support from Rohm Semiconductor. For new designs or long-term production, the active status of the BD9702T-V5 provides supply security.