HDMP-0480 Datasheet | Hewlett-Packard

Features - Supports 1.0625 GBd fibre channel operation - Supports 1.25 GBd gigabit Ethernet (GE) operation - Octal cell PBC in one package - Valid amplitude detection on FM_NODE[7] input - Equalizers on all inputs - High speed LVPECL I/O - Buffered Line Logic (BLL) outputs (no external bias resistors required) - 0.76 W typical power at Vcc=3.3V - 64 Pin, 10 mm, low cost plastic QFP package Applications - RAID, JBOD, BTS cabinets - Four 2:1 muxes - Four 1:2 buffers - 1 = > N gigabit serial buffer - N = > 1 gigabit serial mux Description The HDMP-0480 is an Octal Cell Port Bypass Circuit (PBC). This device minimizes part count, cost and jitter accumulation. Port Bypass Circuits are used in hard disk arrays constructed in Fibre Channel Arbitrated Loop (FC-AL) configurations. By using Port Bypass Circuits, hard disks may be pulled out or swapped while other disks in the array are available to the system. A Port Bypass Circuit (PBC) consists of multiple 2:1 multiplexers daisy chained along with a CDR. Each port has two modes of operation: “disk in loop” and “disk by-passed”. When the “disk in loop” mode is selected, the loop goes into and out of the disk drive at that port. For example, data goes from the HDMP-0480’s TO_NODE[n]± differential output pins to the Disk Drive Transceiver IC’s (e.g. an HDMP-1636A) Rx± differential input pins. Data from the Disk Drive Transceiver IC’s Tx± differential outputs goes to the HDMP- 0480’s FM_NODE[n]± differential input pins. When the “disk bypassed” mode is selected, the disk drive is either absent or non-functional and the loop bypasses the hard disk. The “disk bypassed” mode is enabled by pulling the BYPASS[n]pin low. Leave BYPASS[n]floating to enable the “disk in loop” mode. HDMP-0480’s may be cascaded with other members of the HDMP-04XX/HDMP-05XX family through the FM_NODE and TO_NODE pins to acmodate any number of hard disks. The unused cells in this PBC may be bypassed by using pulldown resistors on the BYPASS[n]- pins for...