Xilinx Virtex-5 RocketIO GTP

112 www.xilinx.com Virtex-5 RocketIO GTP Transceiver User Guide
UG196 (v1.3) May 25, 2007
Chapter 6: GTP Transmitter (TX)
R
Configurable TX Driver
Overview
The GTP TX driver is a high-speed current-mode differential output buffer. To maximize
signal integrity, it includes the following features:
• Differential voltage control
• Pre-emphasis
• Configurable termination impedance
The impact of each of these features on signal integrity depends on the board and the
receiver. See Chapter 10, “GTP-to-Board Interface,” for a detailed discussion of how to use
them to maximize signal integrity. Figure 6-14 shows the different segments of the TX
driver.
Figure 6-14: TX Driver Segments
MGTAVTTTX
TxData[9:0]
TX Serial Clock
MGTTXN
MGTTXP
Main
Pad Driver
Pre-emphasis
Pad Driver
TXPREEMPHASIS[2:0]
TXBUFDIFFCTRL[2:0]
TXDIFFCTRL[2:0]
UG196_c6_14_051107
PISO
10:1
Pre-Driver
Pre-Driver
TXPREEMPHASIS[2:0]