VSC7177XYI

VSC7177XYI Datasheet

VSC7177 Data Sheet

Part	Datasheet
VSC7177XYI	VSC7177XYI (pdf)

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VSC7177 Data Sheet Enhanced 2:1 Port Selector for Serial ATA and Serial Attached SCSI ● 2:1 port selector for both Serial ATA SATA and Serial Attached SCSI SAS links ● Serial ATA compliant at Gbps capable ● Sideband port selection ● Complies with Serial ATA II Port Selector specification including failover control ● Passes Serial ATA patterns transparently ● Programmable receiver sensitivity ● High output swing mode with pre-emphasis ● Compatible with legacy designs VSC7173 and VSC7175 provides enhanced connectivity and signal pre-emphasis ● W to W power dissipation depending on operating mode ● V power supply ● 32-pin, 7 mm x 7 mm QFP-N package ● Active-passive redundant failover systems ● Dual-port Serial ATA and Serial Attached SCSI disk arrays JBODs ● NAS servers ● RAID subsystems ● Disk-based backup systems ● Serial ATA and Serial Attached SCSI routing applications ● Buffers for externally connected links To order the VSC7177 device, see “Ordering Information,” page The VSC7177 is a Serial ATA and Serial Attached SCSI multiplier/buffer that implements a 2:1 port selector function for Gbps and Gbps links. This function is used when dual hosts, such as I/O controllers, must access single-port disk drives in high availability storage subsystems where redundancy and load sharing are important. The outputs from the I/O controllers are muxed to a Serial ATA or Serial Attached SCSI drive. The output from the Serial ATA drive is buffered and replicated to the I/O controllers. When switching from one I/O controller to the other, a Serial ATA link must be re-initialized with out-of-band OOB signals, which are transferred through the VSC7177 transparently. The VSC7177 provides high output swings, pre-emphasis, and programmable receiver sensitivity that are needed to drive long backplanes and external cables. Port connectivity for the device can be configured using driving external I/O pins or through protocol-based port. See the block diagram on page Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at 1 of 24 VSC7177 Block Diagram Port 0 P0INP P0INN P0OUTP P0OUTN Port 1 P0INP P0INN P1OUTP P1OUTN OOB EN OOB EN VSC7177 Data Sheet OOB EN Port 2 P2INP P2INN P2OUTP P2OUTN PORTSEL0 PORTSEL1 MODE1 MODE0 OOBSEL[1:0] HIV[2:0] Port Selection Mode Configuration Pin Configuration SATA II Port Selection Control Logic Mux Select and Output Driver Enable I/O Configuration OOBPORT0 POSLTD 2 of 24 VSC7177 Data Sheet Application Example The VSC7177 allows two Serial ATA hosts to access one Serial ATA drive. Figure 1 shows a common application where redundant I/O controllers in disk arrays have mux access to single-port Serial ATA disk drives. I/O Controller A VSC7177 I/O Controller B Serial ATA Drive 1 of n Backplane "Tailgate" Board Figure Serial ATA Backplane Application 3 of 24 VSC7177 Data Sheet 4 of 24 VSC7177 Data Sheet FUNCTIONAL DESCRIPTIONS Modes of Operation The VSC7177 has two modes of operation sideband port selection and protocol port selection. Each mode corresponds to a different method of configuring port connectivity. Only one of the operating modes is active at any time in the VSC7177. Sideband-based port connectivity is controlled externally using the I/O pins of the device itself. Protocol-based connectivity is implemented as defined in the Serial ATA II Port Selector specification. Selecting Operating Modes There are two types of sideband-based port selections Edge-sensitive and level-sensitive. Rising-edge transitions on the PORTSEL0 and PORTSEL1 inputs cause the corresponding port to become active when in edge-sensitive sideband-based selection mode. Edge-sensitive sideband port selection is enabled when MODE1 is HIGH. PORTSEL0 determines the active port in level-sensitive sideband-based mode. Level-sensitive sideband port selection is enabled when MODE1 is LOW and PORTSEL1 is LOW. Setting MODE1 LOW and PORTSEL1 HIGH in the VSC7177 allows the protocol-based Serial ATA II port selection and test modes to be enabled. PORTSEL0 and MODE0 are used to select these operating modes shown in Table The functionality of the various operating modes is described in the following sections. The setting of PORTSEL1 constitutes one of the primary differences between the VSC7177 and the VSC7173 and the VSC7175. In the VSC7177, PORTSEL1 must be set LOW in level-sensitive sideband mode. The setting of PORTSEL1 has no effect on the operation of the VSC7173 and the VSC7175 in level-sensitive mode it is a “don’t care” . For a complete list of differences between the VSC7177 and the VSC7173 and the VSC7175, see “Pinout Differences Between VSC7177 and VSC7173/VSC7175,” page Table 1 shows how to configure the VSC7177 to operate in any of the various available modes. Table Operating Modes Modes of Operation Edge-sensitive sideband port selection Level-sensitive sideband port selection Reserved Test modes Protocol-based Serial ATA II port selection Test modes MODE1 1 Configuration Pins MODE0 PORTSEL0 PORTSEL1 Select output mode of unconnected port Select output mode of unconnected port edge makes port 0 edge makes port 1 active active Selects connected port X = don’t care = rising. PORTSEL1 must equal VSS in level-sensitive sideband-based port selection mode. The VSC7173 and the VSC7175 allow PORTSEL1 = X. 5 of 24 VSC7177 Data Sheet Sideband-Based Port Selection External I/O pins are used to configure port connectivity when the sideband-based port selection modes are active. The protocol-based port selection mode is disabled when sideband-based port selection modes are enabled. There are two sideband-based port selection operating modes. One mode selects the active port connected to port 2 based on the logical value of the PORTSEL0 input. Port 0 is the active port connected to port 2 when PORTSEL0 is LOW. Port 1 is the active port connected to port 2 when PORTSEL0 is HIGH. This level-sensitive sideband mode is enabled when MODE1 is LOW and PORTSEL1 is LOW. Note that the requirement to have PORTSEL1 LOW in level-sensitive sideband mode does not exist in the VSC7173 and VSC7175. For a complete list of differences between the VSC7177 and the VSC7173 and the VSC7175, see “Pinout Differences Between VSC7177 and VSC7173/VSC7175,” page The other sideband-based mode chooses the active port connected to port 2 when rising edge transitions are detected on the PORTSEL0 and PORTSEL1 input pins. This edge-sensitive sideband-based mode is enabled when MODE1 is HIGH. Port 0 is selected as the active port connected to port 2 when a rising edge transition is detected on PORTSEL0. PORTSEL1 can be in a HIGH or LOW state during a transition of PORTSEL0. Port 1 is selected as the active port when a rising edge transition is detected on PORTSEL1. PORTSEL0 can be in a HIGH or LOW state during a transition of PORTSEL1. The VSC7177 grants access to the last PORTSELx signal that transitions from LOW to HIGH. To allow redundant hosts to access single-port drives in edge-sensitive sideband port selection mode, two inputs, PORTSEL0 and PORTSEL1, control the mux to the drive port and the enable signal to their output port. Because of this, each host needs to gain control of the VSC7177 if the other host fails. It is assumed that if a host fails, it will drive PORTSELx HIGH, LOW, or open, but that it will not be transitioning the signal. It is also assumed that the two hosts have a host-to-host communication path that allows them to agree which host should access the drive at any time. If the host at port 1 fails, the host at port 0 can regain access to the drive by first driving PORTSEL0 LOW, then driving it HIGH. Essentially, the last host to transition its PORTSELx signal from LOW to HIGH is granted access. This simple scheme ensures that a healthy host can always recover access to the drive at port 2 if the other host fails. Status Mode The P0SLTD output reports the OOB status of port 1 OOBPORT1 when the device is in level-sensitive sidebandbased port selection mode. The P0SLTD output indicates the active port when the device is in edge-sensitive sideband-based port selection mode. P0SLTD is LOW when port 1 is active and HIGH when port 0 is active. The OOBPORT0 output reports the state of the OOB detector from port 0’s input receiver. Table 2 contains a summary of this information. For more information about the OOBPORT0 and OOBPORT1 signals, see “OOB Transfer,” page Table Output Status in Sideband Port Selection Mode Sideband Port Selection Mode Level-sensitive Edge-sensitive Edge-sensitive Port Connected to Port 2 Port 0 or 1 Port 0 Port 1 ORDERING INFORMATION The VSC7177 device is available in two package types. VSC7177YI is a 32-pin, quad flat pack with no leads QFP-N and an exposed pad. The device is also available in a lead Pb -free package, VSC7177XYI. Lead Pb -free products from Maxim comply with the temperatures and profiles defined in the joint IPC and JEDEC standard IPC/JEDEC J-STD-020. For more information, see the IPC and JEDEC standard. The following table lists the ordering information for the VSC7177 device. VSC7177 Enhanced 2:1 Port Selector for Serial ATA and Serial Attached SCSI VSC7177YI 32-pin QFP-N, 7 mm x 7 mm x mm body VSC7177XYI Lead Pb -free, 32-pin QFP-N, 7 mm x 7 mm x mm body Maxim Integrated Products 120 San Gabriel Drive Sunnyvale, CA 94086 United States 408-737-7600 Copyright 2004 to 2005 Maxim Integrated Products Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. Maxim retains the right to make changes to its products or specifications to improve performance, reliability or manufacturability. All information in this document, including descriptions of features, functions, performance, technical specifications and availability, is subject to change without notice at any time. While the information furnished herein is held to be accurate and reliable, no responsibility will be assumed by Maxim for its use. Furthermore, the information contained herein does not convey to the purchaser of microelectronic devices any license under the patent right of any manufacturer. Maxim products are not intended for use in life support products where failure of a Maxim product could reasonably be expected to result in death or personal injury. Anyone using a Maxim product in such an application without express written consent of an officer of Maxim does so at their own risk, and agrees to fully indemnify Maxim for any damages that may result from such use or sale. is a registered trademark of Maxim Integrated Products, Inc. All other products or service names used in this publication are for identification purposes only, and may be trademarks or registered trademarks of their respective companies. All other trademarks or registered trademarks mentioned herein are the property of their respective holders. 24 of 24

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VSC7177 Data Sheet

Enhanced 2:1 Port Selector for Serial ATA and Serial Attached SCSI
● 2:1 port selector for both Serial ATA SATA and Serial Attached SCSI SAS links
● Serial ATA compliant at Gbps capable
● Sideband port selection ● Complies with Serial ATA II Port Selector
specification including failover control ● Passes Serial ATA patterns transparently ● Programmable receiver sensitivity ● High output swing mode with pre-emphasis ● Compatible with legacy designs VSC7173 and

VSC7175 provides enhanced connectivity and signal pre-emphasis ● W to W power dissipation depending on operating mode ● V power supply ● 32-pin, 7 mm x 7 mm QFP-N package
● Active-passive redundant failover systems ● Dual-port Serial ATA and Serial Attached SCSI
disk arrays JBODs ● NAS servers ● RAID subsystems ● Disk-based backup systems ● Serial ATA and Serial Attached SCSI routing
applications ● Buffers for externally connected links
To order the VSC7177 device, see “Ordering Information,” page

The VSC7177 is a Serial ATA and Serial Attached SCSI multiplier/buffer that implements a 2:1 port selector function for Gbps and Gbps links. This function is used when dual hosts, such as I/O controllers, must access single-port disk drives in high availability storage subsystems where redundancy and load sharing are important. The outputs from the I/O controllers are muxed to a Serial ATA or Serial Attached SCSI drive. The output from the Serial ATA drive is buffered and replicated to the I/O controllers. When switching from one I/O controller to the other, a Serial ATA link must be re-initialized with out-of-band OOB signals, which are transferred through the VSC7177 transparently. The VSC7177 provides high output swings, pre-emphasis, and programmable receiver sensitivity that are needed to drive long backplanes and external cables.

Port connectivity for the device can be configured using driving external I/O pins or through protocol-based port. See the block diagram on page

Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at
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VSC7177 Block Diagram

Port 0

P0INP P0INN P0OUTP P0OUTN

Port 1

P0INP P0INN P1OUTP P1OUTN

OOB EN

OOB EN

VSC7177 Data Sheet

OOB EN

Port 2

P2INP P2INN

P2OUTP P2OUTN

PORTSEL0 PORTSEL1

MODE1

MODE0 OOBSEL[1:0]

HIV[2:0]

Port Selection Mode

Configuration

Pin Configuration

SATA II Port Selection

Control Logic Mux Select and Output Driver Enable

I/O Configuration

OOBPORT0 POSLTD
2 of 24

VSC7177 Data Sheet

Application Example

The VSC7177 allows two Serial ATA hosts to access one Serial ATA drive. Figure 1 shows a common application where redundant I/O controllers in disk arrays have mux access to single-port Serial ATA disk drives.

I/O Controller A

VSC7177

I/O Controller B

Serial ATA Drive 1 of n

Backplane
"Tailgate" Board

Figure Serial ATA Backplane Application
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VSC7177 Data Sheet
4 of 24

VSC7177 Data Sheet

FUNCTIONAL DESCRIPTIONS

Modes of Operation

The VSC7177 has two modes of operation sideband port selection and protocol port selection. Each mode corresponds to a different method of configuring port connectivity. Only one of the operating modes is active at any time in the VSC7177. Sideband-based port connectivity is controlled externally using the I/O pins of the device itself. Protocol-based connectivity is implemented as defined in the Serial ATA II Port Selector specification.

Selecting Operating Modes

There are two types of sideband-based port selections Edge-sensitive and level-sensitive. Rising-edge transitions on the PORTSEL0 and PORTSEL1 inputs cause the corresponding port to become active when in edge-sensitive sideband-based selection mode. Edge-sensitive sideband port selection is enabled when MODE1 is HIGH.

PORTSEL0 determines the active port in level-sensitive sideband-based mode. Level-sensitive sideband port selection is enabled when MODE1 is LOW and PORTSEL1 is LOW.

Setting MODE1 LOW and PORTSEL1 HIGH in the VSC7177 allows the protocol-based Serial ATA II port selection and test modes to be enabled. PORTSEL0 and MODE0 are used to select these operating modes shown in Table The functionality of the various operating modes is described in the following sections.

The setting of PORTSEL1 constitutes one of the primary differences between the VSC7177 and the VSC7173 and the VSC7175. In the VSC7177, PORTSEL1 must be set LOW in level-sensitive sideband mode. The setting of PORTSEL1 has no effect on the operation of the VSC7173 and the VSC7175 in level-sensitive mode it is a “don’t care” . For a complete list of differences between the VSC7177 and the VSC7173 and the VSC7175, see “Pinout Differences Between VSC7177 and VSC7173/VSC7175,” page

Table 1 shows how to configure the VSC7177 to operate in any of the various available modes.

Table Operating Modes

Modes of Operation Edge-sensitive sideband port selection

Level-sensitive sideband port selection

Reserved Test modes Protocol-based Serial ATA II port selection Test modes

MODE1 1

Configuration Pins

MODE0

PORTSEL0

PORTSEL1

Select output mode of unconnected port

Select output mode of unconnected port
edge makes port 0 edge makes port 1
active
active

Selects connected port

X = don’t care = rising.

PORTSEL1 must equal VSS in level-sensitive sideband-based port selection mode. The VSC7173 and the VSC7175 allow PORTSEL1 = X.
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VSC7177 Data Sheet

Sideband-Based Port Selection

External I/O pins are used to configure port connectivity when the sideband-based port selection modes are active. The protocol-based port selection mode is disabled when sideband-based port selection modes are enabled.

There are two sideband-based port selection operating modes. One mode selects the active port connected to port 2 based on the logical value of the PORTSEL0 input. Port 0 is the active port connected to port 2 when PORTSEL0 is LOW. Port 1 is the active port connected to port 2 when PORTSEL0 is HIGH. This level-sensitive sideband mode is enabled when MODE1 is LOW and PORTSEL1 is LOW. Note that the requirement to have PORTSEL1 LOW in level-sensitive sideband mode does not exist in the VSC7173 and VSC7175. For a complete list of differences between the VSC7177 and the VSC7173 and the VSC7175, see “Pinout Differences Between VSC7177 and VSC7173/VSC7175,” page

The other sideband-based mode chooses the active port connected to port 2 when rising edge transitions are detected on the PORTSEL0 and PORTSEL1 input pins. This edge-sensitive sideband-based mode is enabled when MODE1 is HIGH. Port 0 is selected as the active port connected to port 2 when a rising edge transition is detected on PORTSEL0. PORTSEL1 can be in a HIGH or LOW state during a transition of PORTSEL0. Port 1 is selected as the active port when a rising edge transition is detected on PORTSEL1. PORTSEL0 can be in a HIGH or LOW state during a transition of PORTSEL1. The VSC7177 grants access to the last PORTSELx signal that transitions from LOW to HIGH.

To allow redundant hosts to access single-port drives in edge-sensitive sideband port selection mode, two inputs, PORTSEL0 and PORTSEL1, control the mux to the drive port and the enable signal to their output port. Because of this, each host needs to gain control of the VSC7177 if the other host fails. It is assumed that if a host fails, it will drive PORTSELx HIGH, LOW, or open, but that it will not be transitioning the signal. It is also assumed that the two hosts have a host-to-host communication path that allows them to agree which host should access the drive at any time. If the host at port 1 fails, the host at port 0 can regain access to the drive by first driving PORTSEL0 LOW, then driving it HIGH. Essentially, the last host to transition its PORTSELx signal from LOW to HIGH is granted access. This simple scheme ensures that a healthy host can always recover access to the drive at port 2 if the other host fails.

Status Mode

The P0SLTD output reports the OOB status of port 1 OOBPORT1 when the device is in level-sensitive sidebandbased port selection mode. The P0SLTD output indicates the active port when the device is in edge-sensitive sideband-based port selection mode. P0SLTD is LOW when port 1 is active and HIGH when port 0 is active.

The OOBPORT0 output reports the state of the OOB detector from port 0’s input receiver. Table 2 contains a summary of this information. For more information about the OOBPORT0 and OOBPORT1 signals, see “OOB Transfer,” page

Table Output Status in Sideband Port Selection Mode

Sideband Port Selection Mode Level-sensitive Edge-sensitive Edge-sensitive

Port Connected to Port 2 Port 0 or 1 Port 0 Port 1
ORDERING INFORMATION

The VSC7177 device is available in two package types. VSC7177YI is a 32-pin, quad flat pack with no leads QFP-N and an exposed pad. The device is also available in a lead Pb -free package, VSC7177XYI.

Lead Pb -free products from Maxim comply with the temperatures and profiles defined in the joint IPC and JEDEC standard IPC/JEDEC J-STD-020. For more information, see the IPC and JEDEC standard.
The following table lists the ordering information for the VSC7177 device.

VSC7177 Enhanced 2:1 Port Selector for Serial ATA and Serial Attached SCSI

VSC7177YI
32-pin QFP-N, 7 mm x 7 mm x mm body

VSC7177XYI

Lead Pb -free, 32-pin QFP-N, 7 mm x 7 mm x mm body

Maxim Integrated Products 120 San Gabriel Drive Sunnyvale, CA 94086 United States
408-737-7600

Copyright 2004 to 2005 Maxim Integrated Products

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. Maxim retains the right to make changes to its products or specifications to improve performance, reliability or manufacturability. All information in this document, including descriptions of features, functions, performance, technical specifications and availability, is subject to change without notice at any time. While the information furnished herein is held to be accurate and reliable, no responsibility will be assumed by Maxim for its use. Furthermore, the information contained herein does not convey to the purchaser of microelectronic devices any license under the patent right of any manufacturer.

Maxim products are not intended for use in life support products where failure of a Maxim product could reasonably be expected to result in death or personal injury. Anyone using a Maxim product in such an application without express written consent of an officer of Maxim does so at their own risk, and agrees to fully indemnify Maxim for any damages that may result from such use or sale.
is a registered trademark of Maxim Integrated Products, Inc.

All other products or service names used in this publication are for identification purposes only, and may be trademarks or registered trademarks of their respective companies. All other trademarks or registered trademarks mentioned herein are the property of their respective holders.
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More datasheets: 75844-302-16 | 75844-318-06 | 75844-302-04 | 75844-302-72 | 75844-379-26 | 75844-327-20 | 75844-329-72 | 75844-398-20 | TN6G16-0019P1B | DBMM13W3SA197

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Datasheet ID: VSC7177XYI 647499