88E1240

　　OVERVIEW The Alaska® Quad family of single-chip devices contains four independent Gigabit Ethernet transceivers on a single monolithic IC. Each transceiver performs all the physical layer functions for 100BASE-TX and 1000BASE-T full or half-duplex Ethernet on CAT 5 twisted pair cable， and 10BASET full or half-duplex Ethernet on CAT 3， 4， and 5 cable. The Alaska 88E1240 device supports the Serial Gigabit Media Independent Interface （SGMII） for direct connection to a MAC/Switch port. The 88E1240 device is fully compliant with the IEEE 802.3 standard. The 88E1240 device includes the PMD， PMA， and PCS sublayers. The 88E1240 device performs PAM5， 8B/10B， 4B/5B， MLT-3， NRZI， and Manchester encoding/decoding; digital clock/data recovery; stream cipher scrambling/descrambling; digital adaptive equalization for the receiver data path as well as digital filtering for pulse-shaping for the line transmitter; and AutoNegotiation and management functions. The 88E1240 device support Auto-MDI/MDIX at all three speeds to enable easier installation and reduced installation costs. The 88E1240 device integrates MDI interface termination resistors into the PHY. This resistor integration facilitates board layout and reduces board cost by reducing the number of external components. The new Marvell® calibrated resistor scheme will achieve and exceed the accuracy requirements of the IEEE 802.3 return loss specifications. The 88E1240 device uses advanced mixed-signal processing to perform equalization， echo and crosstalk cancellation， data recovery， and error correction at a gigabit per second data rate. The device achieves robust performance in noisy environments with very low power dissipation. The 88E1240 device is supported with an integrated Advanced Virtual Cable Tester® （VCT™） enabling fault detection and advanced cable performance monitoring.