Providing Power; Overview - Xilinx Virtex-5 RocketIO GTP User Manual

Chapter 10: GTP-to-Board Interface
Table 10-4: Vendor and Device Examples (Continued)
Vendor
Vectron http://www.vectron.com
X2Y http://www.x2y.com
Attenuators,
LLC

Providing Power

Overview

This section focuses on the voltage regulators that directly source each dedicated filter
network connected to one of the analog power supply pins of the GTP_DUAL primitive.
A voltage regulator is characterized by:
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These characteristics are the selection criteria when choosing a voltage regulator for a
design with GTP transceivers. The output voltage noise and the PSRR over frequency are
often neglected but are very important selection criteria.
As a rule-of-thumb guideline, any substantial noise in the frequency range of 1 MHz and
above on the power supply lines contributes to jitter. Depending on the frequency range
and amplitude, this noise can degrade the overall system performance. The AVCC supply
pins, which source the internal analog circuits of the transceivers, and AVCC_PLL, which
sources the shared PLL of the GTP_DUAL primitive, are especially sensitive to power
supply noise.
When designing a complete Power Distribution System (PDS), the PSRR of the whole
system and of each regulator, is load-current and frequency dependent.
212
Website Products
Oscillators
Low
inductance
capacitors
Input voltage range
Output voltage range
Output voltage current
Output voltage tolerance
Output noise voltage
Power supply ripple rejection (PSRR)
www.xilinx.com
Examples
Virtex-5 RocketIO GTP Transceiver User Guide
UG196 (v1.3) May 25, 2007
R
Remarks