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Analog Devices Inc./Maxim Integrated VSC7177XYI
- Part No.:
- VSC7177XYI
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Specialized
- Package:
- 32-VQFN Exposed Pad
- Datasheet:
-
VSC7177XYI.pdf
- Description:
- IC INTERFACE SPECIALIZED 32QFP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
VSC7177XYI from Maxim Integrated is a 2:1 Serial ATA (SATA) and Serial Attached SCSI (SAS) port selector IC designed for high-availability storage subsystems. It implements transparent 1.5 Gbps/3.0 Gbps link muxing between dual hosts and a single-port drive, supports out-of-band (OOB) signal pass-through, delivers programmable receiver sensitivity, and features high-output swing with pre-emphasis for backplane/cable driving. It is used in active-passive failover disk arrays.
For engineers reviewing the VSC7177XYI datasheet, VSC7177XYI pinout, VSC7177XYI application, or VSC7177XYI equivalent, key selection considerations include sideband vs. protocol-based port selection modes, OOB status reporting per unselected host, HIV-controlled output swing/pre-emphasis, MODE0-dependent loopback behavior in sideband mode, and mandatory PORTSEL1 = LOW requirement in level-sensitive sideband operation.
Technical Context
The VSC7177XYI operates in two mutually exclusive modes: sideband-based (edge- or level-sensitive via PORTSEL0/PORTSEL1/MODE1) and Serial ATA II protocol-based (enabled by MODE1=LOW, MODE0=HIGH, PORTSEL1=HIGH, PORTSEL0=LOW). In sideband mode, it supports loopback of unconnected port input data when MODE0=LOW - a functional enhancement over VSC7173/VSC7175.
It integrates three high-speed differential I/O ports (P0IN/P0OUT, P1IN/P1OUT, P2IN/P2OUT), each with independent HIVx-controlled output amplitude (normal: 500–700 mVpp; high-swing: 800–1300 mVpp) and pre-emphasis enablement. OOB detection thresholds are configurable via OOBSEL[1:0], and P0SLTD reports active port status (HIGH = Port 0, LOW = Port 1, HIGH = no active host in protocol mode).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Data Rate | Supports 1.5 Gbps and 3.0 Gbps SATA/SAS links - enables compatibility with both SATA I and SATA II physical layers. |
| Output Swing | Normal mode: 500–700 mVpp; High-swing mode: 800–1300 mVpp - compensates for PCB trace/connector loss in extended backplanes. |
| Pre-emphasis | Enabled when HIVx = HIGH - improves high-frequency signal integrity and data eye opening over long interconnects. |
| Power Dissipation | 625 mW typical (normal swing), 850 mW typical (high swing) - requires thermal management in dense storage modules. |
| Supply Voltage | 3.0 V to 3.6 V (±10%) on VDD - compatible with standard 3.3 V logic rails; internal 1.8 V regulator supplied via VDDN (pin 25). |
| Operating Temp | 0 °C to +90 °C case temperature - validated for industrial-grade storage enclosure environments. |
| OOB Threshold | Configurable nominal (150–250 mV), ±40/80 mV offsets via OOBSEL[1:0] - allows tuning to system noise margin and cable loss. |
Pinout & Package
Package: 32-pin, 7 mm × 7 mm QFP-N (lead-free, RoHS-compliant). Pin 25 (VDDN) supplies internally regulated 1.8 V and must be decoupled with a 4.7 μF capacitor (ESR 0.5–5.0 Ω). Pin 18 (PORTSEL1) must be tied LOW in level-sensitive sideband mode - a key difference from VSC7173/VSC7175.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| P0INP / P0INN | Host Port 0 differential input | Receives SATA/SAS data from Host A; feeds OOB detector and high-speed path to P2OUT. |
| P1INP / P1INN | Host Port 1 differential input | Receives SATA/SAS data from Host B; same OOB/data handling as P0IN. |
| P2INP / P2INN | Device Port differential input | Receives data from single-port SATA/SAS drive; replicated to active host port(s). |
| P0OUTP / P0OUTN | Host Port 0 differential output | Drives Host A only when selected; disabled (DC-bias) otherwise; swing/pre-emphasis controlled by HIV0. |
| P1OUTP / P1OUTN | Host Port 1 differential output | Drives Host B only when selected; disabled otherwise; swing/pre-emphasis controlled by HIV1. |
| P2OUTP / P2OUTN | Device Port differential output | Drives SATA/SAS drive continuously; swing/pre-emphasis controlled by HIV2. |
| PORTSEL0 / PORTSEL1 | Sideband port selection control | PORTSEL0 selects port in level-sensitive mode; PORTSEL1 must be LOW in that mode - critical for board compatibility. |
| MODE0 / MODE1 | Mode configuration inputs | MODE1 selects sideband (HIGH/LOW) vs. protocol (LOW+HIGH) mode; MODE0 controls loopback behavior of unconnected port. |
| P0SLTD | Active port status indicator | Logic HIGH = Port 0 active; LOW = Port 1 active; HIGH = no active host (protocol mode reset state). |
| OOBPORT0 | Unselected host OOB status | Reports OOB detector state of *unselected* host port - differs from VSC7173/VSC7175 which report selected port. |
| HIV0 / HIV1 / HIV2 | Output swing/pre-emphasis control | HIGH enables high-swing mode (800–1300 mVpp) and pre-emphasis; LOW enables normal SATA-compliant swing (500–700 mVpp). |
| VDDN (Pin 25) | Internal 1.8 V regulator output | Must connect external 4.7 μF decoupling capacitor - unused in VSC7173/VSC7175; critical for digital logic stability. |
Key Features
| Feature | Design Value |
|---|---|
| Protocol-based SATA II port selection | Fully implements Serial ATA II: Port Selector 1.0 spec - enables automatic failover using COMRESET/COMWAKE negotiation without sideband pins. |
| Sideband loopback capability | When MODE0 = LOW, unconnected host port outputs looped-back input data - enables diagnostic monitoring and test-mode signaling not available in VSC7173/VSC7175. |
| Configurable OOB detection threshold | Four selectable thresholds (nominal, ±40 mV, –80 mV) via OOBSEL[1:0] - adapts to varying channel loss and noise in backplane vs. cable deployments. |
| High-swing output with pre-emphasis | HIVx-controlled mode delivers >800 mVpp swing and 20–30% amplitude boost on high-frequency edges - extends reach to 30+ inch FR4 traces or external cables. |
| Dual-mode port selection | Hardware-sideband (fast, deterministic) and protocol-based (autonomous, standards-compliant) modes - supports both legacy control and modern failover architectures. |
Applications
| Active-Passive Failover Storage | Dual-Host SATA/SAS JBOD |
|---|---|
|
Use Scenario: Two redundant I/O controllers share access to a single-port SATA disk drive in a RAID subsystem where continuous availability is required. IC Role / Device Role / Timing Role: VSC7177XYI acts as a transparent 2:1 port selector, enabling either host to establish an active SATA link while the other remains in standby. Use Value: Eliminates need for dual-port drives or complex SAS expanders; supports seamless host switchover using OOB signaling without data corruption. |
Use Scenario: A disk array chassis connects multiple single-port SATA/SAS drives to two upstream host controllers via a shared backplane. IC Role / Device Role / Timing Role: VSC7177XYI serves as a per-drive port selector, routing traffic from either host to individual drives based on load balancing or priority policies. Use Value: Enables cost-effective JBOD expansion using commodity single-port drives while maintaining dual-host redundancy and hot-swap support. |
| Network-Attached Storage (NAS) | Serial ATA Routing Backplane |
|
Use Scenario: A NAS server uses dual controller cards for high-availability clustering, accessing shared SATA drive bays through a centralized switching fabric. IC Role / Device Role / Timing Role: VSC7177XYI functions as a failover-aware SATA multiplexer at the drive interface layer, ensuring uninterrupted access during controller maintenance. Use Value: Provides hardware-level redundancy without requiring SATA link renegotiation delays; maintains link training state across failover events. |
Use Scenario: A storage backplane routes SATA signals from front-panel drive slots to rear-mounted controller modules, supporting mixed host configurations. IC Role / Device Role / Timing Role: VSC7177XYI operates as a signal-conditioned SATA repeater/mux, driving long backplane traces with pre-emphasis and high-swing output. Use Value: Compensates for insertion loss up to 15 dB at 1.5 GHz, enabling reliable 3.0 Gbps operation across 20+ cm FR4 backplanes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar SATA/SAS port selector applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| VSC7175 | No VDDN pin (pin 25 unused); PORTSEL1 is "don't care" in level-sensitive mode; pin 9 reports OOB status for Host A (not unselected host); no sideband loopback (MODE0 has no effect on unconnected port output). | Legacy board compatibility where PORTSEL1 is floating or pulled HIGH; simpler sideband control but lacks protocol mode and advanced diagnostics. | Select VSC7175 only for drop-in replacement on existing VSC7175 designs - not pin-compatible with VSC7177XYI due to VDDN and PORTSEL1 requirements. |
| VSC7173 | Same pinout limitations as VSC7175; pin 9 reports OOB status for Port 0; no protocol-based port selection; no pre-emphasis; lower power (0.5 W typical). | Cost-sensitive, low-density storage systems with basic sideband-only control and minimal signal integrity demands. | VSC7173 is functionally superseded by VSC7177XYI - use only if backward compatibility with older schematics is mandatory and protocol mode/high-swing are unnecessary. |
Compared with VSC7175 and VSC7173, the VSC7177XYI adds mandatory VDDN decoupling, strict PORTSEL1 grounding in sideband mode, unselected-host OOB reporting, sideband loopback, and full SATA II protocol compliance - making it the only choice for new designs requiring failover autonomy, extended reach, or diagnostic visibility.
Availability
VSC7177XYI is available at Aetrix Electronics and suitable for active-passive failover storage systems, dual-host SATA/SAS JBODs, and NAS servers requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant lead-free packaging.
Supply support for VSC7177XYI includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and computing applications.
The VSC7177XYI belongs to Maxim's high-speed interface product line, engineered specifically for enterprise storage infrastructure requiring robust SATA/SAS signal integrity, hardware- and protocol-based failover, and backplane-ready signal conditioning.
FAQ
What is the primary function of the VSC7177XYI in a storage system?
The VSC7177XYI serves as a 2:1 Serial ATA and Serial Attached SCSI port selector, enabling two redundant hosts (e.g., I/O controllers) to share access to a single-port SATA/SAS drive. It supports both sideband-controlled and Serial ATA II protocol-based port selection, passes OOB signals transparently, and provides high-output swing with pre-emphasis for driving long backplanes or external cables - all critical for high-availability storage subsystems.
How does the VSC7177XYI differ from the VSC7175 in terms of pin configuration and functionality?
The VSC7177XYI differs from the VSC7175 in three key ways: (1) Pin 25 (VDDN) is an active 1.8 V regulator output requiring a 4.7 μF capacitor - unused in VSC7175; (2) Pin 18 (PORTSEL1) must be tied LOW in level-sensitive sideband mode - a "don't care" in VSC7175; (3) Pin 9 (OOBPORT0) reports OOB status of the *unselected* host port - whereas VSC7175 pin 9 reports Host A status. Additionally, VSC7177XYI supports sideband loopback (via MODE0) and full SATA II protocol mode, both absent in VSC7175.
What are the operating modes supported by the VSC7177XYI, and how are they selected?
The VSC7177XYI supports two mutually exclusive operating modes: sideband-based (edge- or level-sensitive) and Serial ATA II protocol-based. Sideband mode is selected by setting MODE1 = HIGH (edge-sensitive) or MODE1 = LOW + PORTSEL1 = LOW (level-sensitive). Protocol mode is enabled when MODE1 = LOW, MODE0 = HIGH, PORTSEL1 = HIGH, and PORTSEL0 = LOW. Table 1 in the datasheet defines all valid pin combinations and resulting behaviors for each mode.
Does the VSC7177XYI support both SATA I and SATA II data rates, and what signal integrity features does it provide?
Yes, the VSC7177XYI supports both 1.5 Gbps (SATA I) and 3.0 Gbps (SATA II) data rates. It provides programmable receiver sensitivity (via OOBSEL[1:0]), high-output swing (500–1300 mVpp), and pre-emphasis (enabled when HIVx = HIGH) to maintain signal integrity across lossy channels. These features allow reliable operation over extended FR4 backplanes or external cables where insertion loss would otherwise close the data eye.
What is the purpose of the MODE0 pin on the VSC7177XYI, and how does it affect system behavior?
The MODE0 pin on the VSC7177XYI controls the output behavior of the *unconnected* host port in sideband mode. When MODE0 = HIGH, the unconnected port outputs data from Port 2 (the device port); when MODE0 = LOW, it outputs looped-back data from its own input receiver - a feature not present in VSC7173/VSC7175. This loopback capability enables real-time monitoring of inactive host link health and supports diagnostic test modes in storage systems.
VSC7177XYI Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 32-VQFN Exposed Pad
- Packaging:
- Tray
- Product Status:
- Obsolete
- Applications:
- Buffer
- Interface:
- -
- Voltage - Supply:
- 3V ~ 3.6V
- Supplier Device Package:
- 32-QFP-N (7x7)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
VSC7177XYI FAQ
1.How can I place an order for VSC7177XYI through Aetrix?
Please submit a Request for Quotation (RFQ) for VSC7177XYI on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for VSC7177XYI reliable?
The price and inventory of VSC7177XYI are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for VSC7177XYI is usually 5 days.
3.What payment methods are accepted for VSC7177XYI?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for VSC7177XYI transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for VSC7177XYI?
VSC7177XYI orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your VSC7177XYI order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for VSC7177XYI?
For technical support, including VSC7177XYI datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your VSC7177XYI requirements.
6.How does Aetrix verify that VSC7177XYI is sourced from the original manufacturer or authorized distributors?
All VSC7177XYI products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that VSC7177XYI meets industry standards.
7.What is the process for return or replacement of VSC7177XYI?
All VSC7177XYI units undergo pre-shipment inspection (PSI). If there is an issue with VSC7177XYI, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The VSC7177XYI part is unused and in its original packaging.
Return procedure for VSC7177XYI:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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