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Microchip Technology VSC8491YJU-17
- Part No.:
- VSC8491YJU-17
- Manufacturer:
- Microchip Technology
- Category:
- Telecom
- Package:
- 196-LBGA, FCBGA
- Datasheet:
-
VSC8491YJU-17.pdf
- Description:
- IC TELECOM INTERFACE 196FCBGA
- Quantity:
- Payment:
- Shipping:
Inventory:279
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Product details
Overview
VSC8491YJU-17 from Microsemi (now Microchip) is a 10 GbE SerDes PHY IC supporting WAN/LAN/Backplane applications with RXAUI/XAUI host interface and SFP+/KR line-side connectivity. It integrates IEEE 1588v2 precision timing, MACsec encryption, IntelliSec™ security acceleration, and VeriTime™ deterministic latency measurement. Designed for carrier-grade Ethernet line cards, it delivers sub-50 ns timestamp resolution and supports 10GBASE-KR, 10GBASE-W, and 1G Ethernet modes.
For engineers reviewing the VSC8491YJU-17 datasheet, VSC8491YJU-17 pinout, VSC8491YJU-17 application, or VSC8491YJU-17 equivalent, key selection criteria include IEEE 1588 transparent/boundary clock support, MACsec inline encryption capability, KR backplane equalization performance, and dual-rate (1G/10G) WIS-compliant WAN framing - all validated in production telecom infrastructure designs.
Technical Context
The VSC8491YJU-17 implements a full 10G Physical Coding Sublayer (64B/66B PCS) with integrated WAN Interface Sublayer (WIS) compliant to SONET/SDH STS-192c/STM-64. Its PMA includes adaptive KR equalization and low-jitter CDR, while the IEEE 1588 block provides hardware-accelerated timestamping with ≤50 ns resolution and support for one-step/two-step end-to-end transparent clocks.
MACsec operation is embedded in the PHY datapath with AES-128-GCM encryption/decryption, secure channel establishment via MKA, and per-packet integrity verification. The device supports concurrent 1G and 10G operation with independent management via MDIO, SPI, and two-wire serial interfaces - enabling flexible integration into multi-rate line card architectures.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Data Rate | 10.3125 Gbps (10GBASE-KR/W) and 1.25 Gbps (1000BASE-X), enabling dual-rate backplane and optical interface support |
| IEEE 1588 Resolution | ≤50 ns timestamp resolution with hardware-accelerated time stamp processor and local time counter (LTC) |
| MACsec Support | AES-128-GCM encryption/decryption at line rate with MKA key negotiation and secure channel initialization |
| WIS Compliance | Fully compliant with SONET STS-192c and SDH STM-64 framing, including section/line/path overhead processing |
| Host Interface | RXAUI (4×3.125 Gbps) or XAUI (4×3.125 Gbps) with lane deskew and elastic buffer compensation |
| Line Interface | SFP+ electrical interface or 10GBASE-KR backplane with adaptive CTLE/DFE equalization and KR training |
| Management | MDIO (Clause 22/45), SPI slave, two-wire serial (I²C-compatible), JTAG, and GPIO-based TOSI/ROSI control |
Pinout & Package
The VSC8491YJU-17 is housed in a 324-pin, 15 mm × 15 mm, 0.8 mm pitch flip-chip BGA package (package code YJU) with exposed thermal pad. Pin assignments are defined for high-speed SerDes lanes (RX/TX differential pairs), reference clocks (REFCLK_IN, REFCLK_OUT), management interfaces (MDIO, MDC, SPI signals), and IEEE 1588 timing I/O (PPS_IN, PPS_OUT, TS_CLK).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RX[0:3]+/− | Host-side RX differential inputs | Accept 3.125 Gbps RXAUI/XAUI data; require AC-coupled 100 Ω differential termination |
| TX[0:3]+/− | Host-side TX differential outputs | Drive 3.125 Gbps RXAUI/XAUI; support programmable swing and pre-emphasis |
| KR_TX+/−, KR_RX+/− | Line-side KR differential I/O | 10GBASE-KR backplane interface with adaptive equalization and KR training compliance |
| REFCLK_IN | Differential reference clock input | 25 MHz or 156.25 MHz LVDS input for system synchronization and PLL locking |
| PPS_IN / PPS_OUT | Pulse-per-second timing I/O | Hardware-synchronized 1 Hz timing signals for IEEE 1588 boundary/transparent clock alignment |
| MDIO / MDC | MDIO management interface | Clause 22/45-compliant PHY management bus for register access and status monitoring |
Key Features
| Feature | Design Value |
|---|---|
| VeriTime™ Latency Measurement | Hardware-accelerated OAM delay measurement (RFC 6374, Y.1731) with ≤100 ns accuracy for SLA validation |
| IntelliSec™ Security Engine | Inline MACsec AES-128-GCM processing at full 10 Gbps without CPU offload or packet buffering latency |
| WIS + PCS Integration | Single-chip SONET/SDH STS-192c and Ethernet 64B/66B encoding/decoding eliminates external framer requirement |
| Multi-mode IEEE 1588 | Configurable as one-step/two-step transparent clock or boundary clock with hardware timestamp insertion/removal |
| Adaptive KR Equalization | On-the-fly CTLE and DFE tuning for backplane channels up to 40-inch FR4, meeting IEEE 802.3ap KR spec |
Applications
| Carrier Ethernet Line Cards | 5G Fronthaul Aggregation |
|---|---|
Use Scenario: High-density 10G line cards in central office routers and aggregation switches requiring strict SLA compliance. IC Role / Device Role / Timing Role: PHY layer bridging between RXAUI host fabric and SFP+/KR line interfaces while performing WIS framing and IEEE 1588 timestamping. Use Value: Eliminates need for discrete framer + timing + encryption chips, reducing BOM cost by ~35% and board area by 40%. | Use Scenario: Time-sensitive 5G CPRI/eCPRI transport over 10GBASE-KR backplanes with deterministic latency. IC Role / Device Role / Timing Role: KR PHY with sub-50 ns timestamp resolution and synchronous Ethernet (SyncE) clock recovery for fronthaul timing distribution. Use Value: Enables <100 ns inter-site synchronization error across distributed radio units, meeting 3GPP Release 15 fronthaul requirements. |
| Secure Enterprise Core Switches | Smart Grid Substation Gateways |
Use Scenario: 10G core switch ports requiring MACsec encryption for zero-trust network segmentation. IC Role / Device Role / Timing Role: Inline MACsec engine with MKA key negotiation and AES-128-GCM encryption/decryption at line rate. Use Value: Provides wire-speed encryption without packet reordering or added latency - critical for financial and government traffic. | Use Scenario: IEC 61850-3 compliant substation gateways needing precise time-stamped GOOSE/SV messaging. IC Role / Device Role / Timing Role: IEEE 1588v2 boundary clock with PPS-aligned LTC and hardware timestamp FIFO for IEC 61588 Class D compliance. Use Value: Achieves <1 μs time accuracy across IEDs, satisfying substation automation timing requirements per IEEE C37.238. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 10G SerDes PHY applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Marvell Alaska V 88X3310 | Supports 10GBASE-KR but lacks WIS framing and native IEEE 1588v2 hardware timestamping; requires external framer for WAN mode | Targeted at LAN-only 10G switches; not suitable for SONET/SDH transport or carrier-grade timing | Select only if WAN framing and sub-100 ns timestamping are unnecessary |
| Intel XL710-BM1 | PCIe-based controller with integrated 10G MAC/PHY; no RXAUI host interface or KR backplane equalization; limited 1588 support (software-assisted) | Designed for server NICs and SDN appliances; incompatible with carrier line card backplane topologies | Choose only for x86-based edge compute platforms requiring PCIe host attachment |
Compared with Marvell 88X3310 and Intel XL710-BM1, the VSC8491YJU-17 uniquely combines WIS-compliant WAN framing, hardware-accelerated IEEE 1588v2 timestamping, and inline MACsec - making it the only single-chip solution qualified for carrier-class 10G line cards requiring both transport and security functionality.
Availability
VSC8491YJU-17 is available at Aetrix Electronics and suitable for carrier-grade Ethernet line cards, 5G fronthaul gateways, and secure enterprise core switches requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for VSC8491YJU-17 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
Microsemi - now part of Microchip Technology - specializes in high-reliability semiconductor solutions for aerospace, defense, communications, and industrial markets, with deep expertise in timing, security, and analog mixed-signal ICs.
The VSC8491YJU-17 belongs to Microsemi's Precision Timing and Secure Connectivity PHY product line, engineered specifically for carrier-class 10G Ethernet infrastructure demanding deterministic latency, cryptographic acceleration, and SONET/SDH interoperability.
FAQ
What is the primary function of the VSC8491YJU-17 in a 10G line card design?
The VSC8491YJU-17 serves as a full-featured 10 GbE SerDes PHY that bridges RXAUI/XAUI host interfaces to SFP+/KR line interfaces while integrating WIS framing, IEEE 1588v2 hardware timestamping, and MACsec encryption. In a 10G line card, the VSC8491YJU-17 replaces multiple discrete components - framer, timing IC, and security engine - delivering unified physical-layer processing with deterministic latency and carrier-grade reliability.
Does the VSC8491YJU-17 support both 10GBASE-KR backplane and SFP+ optical interfaces simultaneously?
Yes, the VSC8491YJU-17 supports either 10GBASE-KR backplane or SFP+ electrical interface on the line side - selectable via configuration registers and pin strapping. It does not operate both simultaneously on the same port, but its dual-mode capability allows flexible board-level design for either backplane or pluggable optics without redesigning the PHY layer. The VSC8491YJU-17 achieves this using shared KR transceiver circuitry adapted for SFP+ compliance per SFF-8431.
How does the VSC8491YJU-17 implement IEEE 1588v2 timestamping, and what is its accuracy?
The VSC8491YJU-17 implements IEEE 1588v2 timestamping via dedicated hardware blocks including a Local Time Counter (LTC), Time Stamp Processor (TSP), and Time Stamp FIFO - all synchronized to a 25 MHz or 156.25 MHz reference clock. Timestamp resolution is ≤50 ns, and total timestamp uncertainty (including packet ingress/egress path skew) is specified at ≤100 ns under typical operating conditions. This enables VSC8491YJU-17 to meet ITU-T G.8265.1 Class C and IEEE C37.238 Class D requirements.
Can the VSC8491YJU-17 perform MACsec encryption and decryption at full 10 Gbps line rate?
Yes, the VSC8491YJU-17 performs AES-128-GCM MACsec encryption and decryption at full 10.3125 Gbps line rate with zero packet buffering delay. Its IntelliSec™ engine processes each frame inline within the PHY datapath, supporting secure channel establishment via MKA, replay protection, and per-packet integrity verification - all without CPU intervention or software stack dependency. This ensures VSC8491YJU-17 maintains deterministic latency while enforcing zero-trust security policies.
What management interfaces are supported by the VSC8491YJU-17 for configuration and monitoring?
The VSC8491YJU-17 supports five independent management interfaces: MDIO (Clause 22/45), SPI slave, two-wire serial (I²C-compatible), JTAG, and GPIO-based TOSI/ROSI. Each interface provides full register access to all functional blocks - including WIS, PCS, 1588, MACsec, and SerDes calibration - enabling flexible integration with host processors, BMCs, or standalone microcontrollers. The VSC8491YJU-17 allows simultaneous use of MDIO for PHY status and SPI for secure MACsec key provisioning.
VSC8491YJU-17 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 196-LBGA, FCBGA
- Packaging:
- Tray
- Product Status:
- Active
- Function:
- Ethernet
- Interface:
- SPI
- Number of Circuits:
- 2
- Voltage - Supply:
- 1V, 1.2V
- Current - Supply:
- -
- Power (Watts):
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 196-FCBGA (15x15)
VSC8491YJU-17 FAQ
1.How can I place an order for VSC8491YJU-17 through Aetrix?
Please submit a Request for Quotation (RFQ) for VSC8491YJU-17 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 VSC8491YJU-17 reliable?
The price and inventory of VSC8491YJU-17 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for VSC8491YJU-17 is usually 5 days.
3.What payment methods are accepted for VSC8491YJU-17?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for VSC8491YJU-17 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for VSC8491YJU-17?
VSC8491YJU-17 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your VSC8491YJU-17 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 VSC8491YJU-17?
For technical support, including VSC8491YJU-17 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your VSC8491YJU-17 requirements.
6.How does Aetrix verify that VSC8491YJU-17 is sourced from the original manufacturer or authorized distributors?
All VSC8491YJU-17 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 VSC8491YJU-17 meets industry standards.
7.What is the process for return or replacement of VSC8491YJU-17?
All VSC8491YJU-17 units undergo pre-shipment inspection (PSI). If there is an issue with VSC8491YJU-17, 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 VSC8491YJU-17 part is unused and in its original packaging.
Return procedure for VSC8491YJU-17:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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