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VIA VT6421 - Serial RAID Controller

This product is available fully ROHS-compliant.

The VIA VT6421 controller delivers the benefits of Serial ATA and RAID in a cost effective and easily integrated single chip package, providing Serial ATA technology to enable platform providers and systems builders to satisfy the requirements of multiple market segments.  
Key Features

» Supports RAID Level 0, Level 1, and JBOD
» Supports data transfer rates of up to 150Mbps
» Supports combo-solutions with USB2.0, Firewire, and Gigabit Ethernet

Supporting PCI and Cardbus (PCMCIA) interfaces, the VIA VT6421 provide card vendors the flexibility to design Serial ATA RAID controller cards for the PCs and mobile systems. The VIA Vectro VT6421 enables combo solutions with USB2.0 and IEEE1394, allowing customers to combine new emerging communication technologies with Serial ATA functionality, extending support for physical storage interfaces to external peripheral devices, while maintaining connectivity to the installed base.

Benefits of VIA Vectro VT6421

Support for Serial ATA and Ultra ATA/133/100/66 enables system builders to add complete ATA and ATAPI drive support to their product line-up. Additional support for combo solutions extends connectivity options, increasing flexibility for system builders to design a variety of Serial ATA RAID controller cards, satisfying requirements of multiple market segments.

The dual channel Serial ATA of the VIA VT6421 provides data transfer rates of up to 150MB/s per channel, faster than any previous IDE interface and supporting up to two SATA devices.

Flexible Configuration Options
Supporting multi-level RAID, the VIA VT6421 enables end users to configure their hard drives for maximum performance, maximum assurance for critical data security or maximum capacity, while backwards compatible to the Parallel ATA specification, enabling connectivity to the installed base.

The compact design of the VIA VT6421 together with Serial ATA benefits, including simpler cabling and smaller connectors provide scope for system design innovation within the chassis and allows for small compact PC chassis, with hot plugging capability.


Compliant with the Serial ATA specification 1.0, the VIA VT6421 offers high performance Serial ATA RAID functionality to the full spectrum of PC processor platforms for desktops, mobile systems and servers. Supporting all kinds of ATA and ATAPI devices, including HDDs, CDs, DVDs, high capacity removable devices and featuring 32-bit PCI and PCMCIA interfaces, the VIA VT6420 enables seamless transition to the emerging Serial ATA technology for PCs and mobile systems.

The VIA VT6421 features two Serial ATA channels, supporting up to two devices and one Parallel ATA channel supporting two devices. Featuring PCMCIA interface, the Cardbus mode supports up to two Serial ATA devices. With dual channel Serial ATA, the VIA VT6421 delivers 12% more bandwidth than ATA-133 for data transfer between storage devices and CPU, bursting up to 150Mbps of data per channel and offering a significant performance improvement in data intensive and bulk storage application.

The VIA VT6421 provides multilevel RAID support including RAID level 0 for maximum performance, RAID Level 1 for maximum security and JBOD. To ensure backwards compatibility the VIA VT6421 also integrates a single channel parallel ATA-133 controller, eliminating the need for adaptors.

Featuring simple and practical cabling for improved airflow in the chassis, the VIA VT6421 enables OEMs and system builders to design smaller chassis, satisfying market demand for smaller and more compact PC systems. Smaller cable connectors with improved silicon design with a common location for both 3.5 inch and 2.5 inch drives save space and simplifies PC integration tooling and chassis design, while the lower voltage signaling of the VIA VT6421 alleviates the 5V tolerance support for Parallel ATA designs. Being compatible with a wide range of ATA and ATAPI devices, the VIA VT6421 equips OEMs and system builders with the flexibility to reach multiple market segments and price points.

The VIA VT6421 is the ideal solution for PC and mobile systems users to easily upgrade their storage devices and incorporates the emerging Serial ATA RAID standard into their systems, taking full advantage of the higher bandwidth, faster data transfer rates, improved data integrity and robustness of Serial ATA technology. Featuring a point-to-point host to device connection, installation is simple without the need for configuration as no jumper setting is required.

Backward compatibility with existing operating system drivers, the VIA VT6421 requires no update to software. The VIA VT6420 is compatible with a complete range of Intel, AMD and VIA based processing platforms, Microsoft Windows® 9x/ME/NT4/2K/XP and major Linux based Operating Systems.

Block Diagram

Key Features

RAID Controller
» Supports RAID Level 0, RAID Level 1 and JBOD

PCI Interface
» 33 MHz operation
» Supports PCI 2X mode and PCI native modes
» Complies with PCI Local Bus Specification Revision 2.2

Ultra ATA-133 / IDE interface
» Single channel master mode hard disk controller supporting two enhanced IDE devices
» Redefined Bus Master Programming interface for IDE controllers to support up to four bus masters in a single function
» Supports ATA PIO mode 4, multi-word DMA mode 2 drivers and UltraDMA- mode6
» Extension to Ultra DMA-133 interface for up to 133MB/s transfer rate
» Complies with ATA/ATAPI-6

Serial ATA Interface
» Complies with Serial ATA Specification Revision 1.0
» Supports internal PHY with each PHY supporting up to two SATA devices
» Dual channel master mode PCI supporting up to two SATA devices
» Support data transfer rates of up to 150Mbps per SATA channel

Other Features
» Supports external FLASH or EEPROM for BIOS expansion and RAID functions

Power Supply
» 3.3V for PCI and IDE operation
» 2.5V for Oscillator and Serial ATA port operation

» 0.22um, lower power CMOS process
» 14x20mm, 128 pin PQFP


VIA VT6421 press release
VIA VT6421 image kit (hi-res) / VIA Vectro VT6421 image kit (low-res)

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