FDMF6708N Equivalent & Substitute Parts

Part Overview

The FDMF6708N is a half bridge driver IC designed for synchronous buck converter applications, manufactured by onsemi in the XS™ DrMOS series. This component integrates gate driver functionality with integrated MOSFETs in a 40-PQFN (6x6) package, delivering 50A output current capability. The part is currently listed as obsolete, making equivalent substitutes necessary for new designs or production continuity.

Substiute Parts

FDMF6708N

onsemiIn Stock: 5770FDMF6708N Datasheet

Current PartRFQ

SIC780CD-T1-GE3

Vishay SiliconixIn Stock: 17636SIC780CD-T1-GE3 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

The SIC780CD-T1-GE3 qualifies as a functional equivalent based on the following critical parameters:

• Output Configuration: Both parts implement half bridge topology
• Current Rating: Both deliver 50A output per channel
• Supply Voltage: Both operate within 4.5V ~ 5.5V range
• Operating Temperature: Both rated -40°C ~ 150°C (TJ)
• Interface & Technology: Both use PWM interface with DrMOS technology
• Fault Protection: Both include over temperature, shoot-through, and UVLO protection
• Core Features: Both incorporate bootstrap circuit and status flag functionality

The primary difference lies in package format and load voltage range, which are application-dependent considerations rather than functional limitations.

Parameter Comparison

Engineering Selection Recommendations

The SIC780CD-T1-GE3 is the designated substitute for the obsolete FDMF6708N. Selection criteria are based on:

Product Status: The FDMF6708N is obsolete, while the SIC780CD-T1-GE3 maintains active production status, ensuring long-term availability and supply chain continuity.

Electrical Compatibility: Both parts meet identical specifications for supply voltage (4.5V ~ 5.5V), output current (50A), operating temperature range (-40°C ~ 150°C), and fault protection mechanisms.

Compliance & Certifications: Both parts carry identical ECCN (EAR99), HTSUS (8542.39.0001), and MSL ratings (1 - Unlimited), ensuring regulatory equivalence.

Load Voltage Consideration: The SIC780CD-T1-GE3 supports 4.5V ~ 18V load voltage versus the FDMF6708N's 3V ~ 24V range. Applications requiring load voltages below 4.5V or above 18V require design review.

Package Transition: The SIC780CD-T1-GE3 uses PowerPAK® MLP66-40 packaging versus the FDMF6708N's 40-PowerTFQFN. PCB layout modifications are required for package migration.

Frequently Asked Questions (FAQ)

Q: Can the SIC780CD-T1-GE3 directly replace the FDMF6708N without design changes?

A: Electrical functionality is equivalent for applications within the 4.5V ~ 18V load voltage range. However, package geometry differs, requiring PCB layout redesign. Pin-to-pin compatibility must be verified against specific application schematics.

Q: What is the impact of the load voltage range difference?

A: The FDMF6708N supports 3V ~ 24V load voltage, while the SIC780CD-T1-GE3 supports 4.5V ~ 18V. Applications operating below 4.5V or above 18V cannot use the substitute without alternative solutions.

Q: Are there differences in thermal performance between these parts?

A: The FDMF6708N specifies Rds On values (900mOhm LS, 800mOhm HS). The SIC780CD-T1-GE3 does not provide published Rds On specifications in the available data. Thermal analysis should reference detailed datasheets for accurate power dissipation calculations.

Q: What packaging considerations apply to this substitution?

A: The FDMF6708N uses 40-PowerTFQFN (6x6) while the SIC780CD-T1-GE3 uses PowerPAK® MLP66-40. These are different package families with distinct footprints, requiring complete PCB redesign for the substitute part.

Q: Are both parts RoHS compliant?

A: The FDMF6708N does not specify RoHS status in available data. The SIC780CD-T1-GE3 is ROHS3 compliant. Compliance requirements should be verified against specific application standards.

Q: What additional features does the SIC780CD-T1-GE3 provide?

A: The SIC780CD-T1-GE3 includes diode emulation functionality in addition to the bootstrap circuit and status flag present in both parts. This feature may provide operational benefits in specific synchronous buck converter topologies.