1. UMD Jan 2004 1 Overview Fanout Card (in GLOBAL mode) Fanout Card (in CRATE mode) Fanout Card (in CRATE mode) Fanout Card (in CRATE mode) Unique board for HCAL (and ECAL ?) One board per crate HTRHTR HTRHTR HTRHTR DCCDCC HTRHTR HTRHTR HTRHTR DCCDCC HTRHTR HTRHTR HTRHTR DCCDCC … … Rack-to-Rack CAT7

2. UMD Jan 2004 2 Jeremy’s Schematic (simplified) TTCrx TTC fiber Clk80 Input from GLOBAL Fanout 18 Outputs 40MHz RX_CLK = 40MHz RX_BC0 BC0 FPGA RX_CLK = 40MHz RX_BC0 QPLL 80MHz X-tal Path without QPLL, coming from another rack will increase jitter

3. UMD Jan 2004 3 Alterative scheme… TTC fiber Clk80 Input from GLOBAL Fanout 18 Outputs 40MHz RX_CLK = 40MHz RX_BC0 BC0 FPGA RX_CLK = 40MHz RX_BC0 TTCrx QPLL 40MHz QPLL can run stand-alone and replace the crystal

4. UMD Jan 2004 4 + Resistor (removed in Global mode) TTC fiber Clk80 Input from GLOBAL Fanout 18 Outputs 40MHz RX_CLK = 40MHz RX_BC0 BC0 FPGA RX_CLK = 40MHz RX_BC0 TTCrx QPLL 40MHz 0 