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Mindspeed's Skyrail Transceiver Enables Seamless Upgrade of Existing Systems To OC-48 And 0C-192

Octal SkyRail SERDES is Industry's First Transceiver to Offer an Adaptive High-Speed Interface between LVDS and CML

The manufacturer says . . .

ChipCenter's Paul O'Shea says . . .

Mindspeed Technologies, the Internet infrastructure business of Conexant Systems, Inc, today introduced the industry's first CMOS octal serializer/deserializer (SERDES) transceiver that enables networking equipment manufactures to offer their customers seamless system upgrades from OC-12 to OC-48 and OC-192 speeds. Offering an adaptive high-speed interface between LVDS and CML, and the ability to operate at both 622Mbps (OC-12) and 2.488Gbps (OC-48), the M27218 Octal SkyRail is the only transceiver that allows manufacturers to design system upgrades that protect expensive investments in existing backplanes and port cards. "Until now, there was no simple way to upgrade network equipment manufacturers' backplanes to handle parallel un-encoded data and high-speed serial traffic along the same data path," said Elie Massabki, director of marketing with Mindspeed's Broadband Internetworking Systems business unit. "With Mindspeed's M27218 Octal SkyRail transceiver our customers can design upgrades to OC-48 or OC-192 using legacy backplanes to protect their customer's investments in existing systems and low-speed port cards while increasing port density and throughput by a factor of four." The M27218 is equipped with Amplif-Eye3(TM) Mindspeed's third-generation patented signal conditioning circuitry, enabling manufacturers to provide superior signal integrity while upgrading existing FR-4 backplanes to higher speeds. SERDES transceivers provide serial connectivity between internal system components such as line cards and switching elements where high bandwidth and minimum connector pin count are required. The M27218 is a very low-power transceiver with total power consumption of less than 2.5 Watts at 2.488Gbps. It is optimized for a wide range of communications equipment requiring the LVDS/CML interface to operate at 2.488GBPS or 622Mbps, including add/drop multiplexers, optical cross-connects, multi-service switches, routers and network aggregators. Mindspeed's SkyRail family offers the broadest range of SERDES transceivers in the industry - including single (CX27201), quad (M27207/M27205), and octal (M27211/M27218) devices - for the widest range of performance and highest data rates per channel of any other transceiver family currently available. The M27218 Octal SkyRail transceiver is an eight-channel SERDES device capable of operating from 400Mbps to 3.2Gbps. It integrates eight serial LVDS/CML transmitters and receivers that can adapt and interface to LVDS or CML/LVPECL inputs/outputs. It also integrates 32 parallel LVDS transmitters and receivers, selectable 4:1/1:4 and 1:1 SERDES functions, clock and data recovery, synthesis circuitry, termination resistors and de-skew buffers. The M27218 offers AC and DC coupling capability and can accept more than 1,000 consecutive identical digits. The Amplif-Eye3 signal conditioning circuitry provides optimal signal integrity over standard FR-4 trace and legacy connectors through multi-level pre-emphasis on the transmitter and equalization on the receiver. Amplif-Eye3 optimizes and maximizes the transceiver's reach, driving more than 60 inches (one and a half meters) of standard FR-4 backplane traces and two connectors at 2.488Gbps. The M27218 also features low transmit jitter, high receive jitter tolerance, and receiver input sensitivity of 50 mV which further enhances performance and robustness. The M27218 transceiver also incorporates Mindspeed's Flexilink parallel LVDS interface. Flexilink simplifies system design and provides multiple clocking modes with adjustable timing to facilitate the interface of different application-specific integrated circuits (ASICs), which operate with different clocking and timing implementations. For more information: Conexant Mindspeed

The M27218 transceiver offers the signal conditioning circuitry needed to drive very long traces along the backplane. It uses Mindspeed's third generation of signal conditioning (Amplif-Eye3), so it has all the bells and whistles needed to drive very long traces - as long as 65 inches of standard FR4 and two connectors. This is an impressive gain from their first generation SERDES device that could drive 12 inches at 3.125Gb/s. The signal conditioning also has gone from a simple one-level of pre-emphasis to multi-level of pre-emphasis, and to multi-tasks and multi-levels of multi-tasking. The company also added multiple levels of equalization and finally they added their own recipe for signal conditioning to complement their pre-emphasis and equalization. The primary market for the M27218 is for the backplane, switches, and routers used for enterprise storage and the carrier-class equipment. Mindspeed developed this transceiver in response to requests by customers whose older technology had reached its limit. These customers were using Low Voltage Differential Signaling (LVDS) technology, which was the best out there about 3 or 4 years ago. Now they had problems: They needed to cover the range from 622Mb/s up to 2.5Gb/s to support OC-12 to OC-48. They needed the capability to handle very long strings of zeros or ones. They needed to modify or adapt the interface from LVDS to whatever can handle 2.5Gb/s speeds because the LVDS that they were using couldn't handle 2.5Gb/s. This means they would have to change to a technology that runs at those speeds such as Current Mode Logic (CML) or Low Voltage Positive Emitter Coupled Logic (LVPECL), and they incur the costs to make those upgrades. They wanted the capability to upgrade without losing their older technology. The M27218 was developed to address those issues. It can adapt and sense the interface. Additionally, it behaves like an LVDS at lower speeds and at higher speeds it can behave like a CML. This is no trivial accomplishment because today's SERDES technology can't accommodate parallel data across the same data path, and it doesn't simultaneously run across a wide range of frequencies. To handle the long strings of zeros and ones, Mindspeed uses either AB10B or 6466 technology. It codes or scrambles the data so there are enough transitions from 0 to 1 enabling the PLLs to detect a signal and recover the data. Today the most stringent coding occurs with SONET streams that potentially could have 72 consecutive zeros. When you get that many consecutive zeros the PLL will lose its lock and won't be able to recover data. This product is important for carriers because the biggest investment for carriers is in port cards, even as the requirements for throughput and speed increase. As carriers try to scale up to handle OC-12 or -48 or -192, they also need to modify line cards to handle those speeds. Inside the line card is an ASIC that interfaces to a backplane at 622 Mb/s, and goes to the switch and interfaces to the port card through the 622 Mb/s LVDS line. The Mindspeed 27218 sits between the ASIC and the backplane, the switch and backplane, or between the switch and the port card. With that position users can maintain the same type of traffic and they don't have to overhaul the whole system, re-architect the system, or change all their port cards to run at the higher speeds. The device does 4:1 or 1:4 serialization and deserialization so it can map 4 incoming LVDS (parallel) signals into one high-speed signal (serial), which can be LVDS or CML, depending on the backplane interface. Also, it has a pass-through mode to support the legacy, low-speed port cards that have 622Mb/s. Additionally, the device can be configured per channel. So one channel could be running at 622Mb/s and another could be running at 2.5 Gb/s. The M27218 has some other worthwhile features including: built-in impedance termination resistors, diagnostic testing capabilities, loop-back capabilities that generate patterns so it can test adjacent devices, a self-test of the SERDES, and there's a Serial Peripheral Interface (SPI) that allows the CPU interface to program all the features, manage all the controls, get all the indicators from the device, and set up all configuration settings. Compared to other competitors power consumption, this chip fares very well. The entire octal consumes 2.5W of power compared to some quad chips that consume 3W. Mindspeed says that they managed to get power dissipation down to such low levels with their unique PLL technology and because the device does a lot of function sharing. The company uses a 0.18-micron process technology which helps lower the power. However, they claim that the ability to share some circuitry is the key to reducing the needed power inside the device, especially as they get into higher levels of integration. The M27218 Octal SkyRail SERDES transceiver will sample in July and volume production will begin in the fourth quarter of 2002. Packaged in a 23mm-x-23mm, 324-pin HSFBGA, the M27218 OEM price is $109 in volumes of 1,000. For more information click here: Product Brief.

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