FDMF6821C Half Bridge Driver Equivalent & Substitute Parts

Part Overview

The FDMF6821C 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 for efficient power conversion in inductive load applications. The product is currently obsolete, making identification of functionally equivalent alternatives essential for design continuity and procurement planning.

Substiute Parts

FDMF6821C

onsemiIn Stock: 2281FDMF6821C Datasheet

Current PartRFQ

SIC780CD-T1-GE3

Vishay SiliconixIn Stock: 17636SIC780CD-T1-GE3 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the FDMF6821C is determined by the following critical parameters:

• Output Configuration: Half bridge topology is mandatory for buck converter applications
• Current Rating: 50A output per channel is the functional requirement
• Supply Voltage: 4.5V ~ 5.5V input range must be supported
• Load Voltage Range: Acceptable range for output voltage regulation
• Operating Temperature: -40°C ~ 150°C junction temperature capability
• Interface Type: PWM control interface for synchronous buck operation
• Technology: DrMOS integrated driver and MOSFET architecture
• Fault Protection: Over temperature, shoot-through, and UVLO protection are required
• Compliance: ROHS3 compliance and MSL rating for manufacturing compatibility

The SIC780CD-T1-GE3 meets these substitution criteria through equivalent functional specifications and compatible electrical parameters.

Parameter Comparison

Engineering Selection Recommendations

The SIC780CD-T1-GE3 is a functionally equivalent substitute for the obsolete FDMF6821C based on the following factors:

Electrical Equivalence: Both devices meet the core electrical specifications for synchronous buck converter applications, including 50A output current, 4.5V ~ 5.5V supply voltage, PWM interface, and identical operating temperature range.

Protection Features: Both parts provide equivalent fault protection mechanisms (over temperature, shoot-through, UVLO) and bootstrap circuit functionality required for half bridge driver operation.

Compliance Status: The SIC780CD-T1-GE3 maintains ROHS3 compliance and MSL 1 rating, ensuring compatibility with current manufacturing and supply chain requirements.

Product Status: The SIC780CD-T1-GE3 is active in production with substantial inventory availability (17,547 pcs), providing supply continuity for the obsolete FDMF6821C.

Package Consideration: The substitute uses PowerPAK® MLP66-40 packaging versus the 40-PowerTFQFN (6x6) of the original part. PCB layout and thermal management design verification is required to confirm mechanical and thermal compatibility in the target application.

Frequently Asked Questions (FAQ)

Q: Can the SIC780CD-T1-GE3 directly replace the FDMF6821C without PCB modifications?

A: Electrical functionality is equivalent, but the packages differ (PowerPAK® MLP66-40 versus 40-PowerTFQFN). PCB footprint, trace routing, and thermal pad design must be evaluated for compatibility. Direct pin-for-pin substitution cannot be assumed.

Q: What is the significance of the wider load voltage range (4.5V ~ 18V) in the SIC780CD-T1-GE3?

A: The substitute supports a broader output voltage range than the original part (3V ~ 16V). This provides design flexibility for applications requiring higher output voltages while remaining compatible with designs operating within the original 3V ~ 16V specification.

Q: Are the Rds On specifications equivalent between the two parts?

A: The FDMF6821C specifies 1Ohm for both low-side and high-side switches. The SIC780CD-T1-GE3 does not provide Rds On values in the available data. Detailed datasheets must be consulted to confirm on-resistance characteristics for thermal and efficiency analysis.

Q: Does the additional diode emulation feature in the SIC780CD-T1-GE3 affect compatibility?

A: Diode emulation is an additional feature that does not conflict with applications designed for the FDMF6821C. It may provide improved light-load efficiency in synchronous buck converter designs.

Q: What compliance certifications apply to both parts?

A: Both the FDMF6821C and SIC780CD-T1-GE3 are ROHS3 compliant with MSL 1 (unlimited moisture sensitivity level) ratings, meeting current environmental and manufacturing standards.