Power Supply Requirements; Determining Power Supply Budget - Xilinx Virtex-4 RocketIO User Manual

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Power Supply Requirements

The Virtex-4 Data Sheet should be used for power consumption specifications for an MGT
tile.

Determining Power Supply Budget

Due to the shared transmitter resources, a current consumption budget must be based on
the number of tiles and single transmitters used. Current draw depends on VCO and data
rate. A conservative estimate always uses maximum current draw specifications obtained
from the Virtex-4 Data Sheet, Table 3 and Table 4, at a data and/or VCO rate equal to or
greater than the operating data rate.
consumption:
Where:
The current consumed by the V
between the transmitter and receiver termination networks and their respective voltages.
The preferred manner of connecting the transmitter and receiver is internal AC coupling
with external DC coupling (see
which a RocketIO transmitter or receiver is coupled to another RocketIO MGT or coupled
to a transceiver from another vendor, provided the termination networks have a CML
topology.
Virtex-4 RocketIO MGT User Guide
UG076 (v4.1) November 2, 2008
AVCCAUXTX Current Consumption =
[I x M] + [0.7 x T x I
CCAUXTX[MAX]
+ [I
CCAUXTX[POWERDOWN]
AVCCAUXRX Current Consumption =
[I x R] + [0.55 x I
CCAUXRX[MAX]
+ [0.45 x I
CCAUXRX[MAX]
AVCCAUXMGT Current Consumption =
[I x (N – Z)] + [I
CCAUXMGT[MAX]
N = total available tiles (6 for the FX20, 10 for the FX100)
M = the number operating tiles that use both transmitters
T = the number of operating transmitters with a shared transmitter that is not
operating
R = the number of operating tiles that use both receivers
Q = the number of operating MGTA receivers with an MGTB receiver in the same
tile that is not operating
S = the number of operating MGTB receivers with an MGTA receiver in the same
tile that is not operating
Z = the number of tiles in total power-down
I ]
CCAUXTX[POWERDOWN
I ]
CCAUXRX[POWERDOWN
I ]
CCAUXMGT[POWERDOWN
I
TTX[OPEN_CIRCUIT]
I
TRX[OPEN_CIRCUIT]
Equation 6-4 and Equation 6-5
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Equation 6-1 through
]
CCAUXTX[MAX]
x Z]
x Q]
CCAUXRX[MAX]
x S] + [I
CCAUXRX[POWERDOWN]
CCAUXMGT[POWERDOWN]
= I
CCAUXTX[QUIESCENT]
= I
CCAUXRX[QUIESCENT]
= I
CCAUXMGT[QUIESCENT]
= I
TTX[QUIESCENT]
= I
TRX[QUIESCENT]
and V pins depends on the coupling scheme
TTX TRX
Figure 6-2). This requirement applies to applications in
are valid only when V
Physical Requirements
Equation 6-3 calculate current
Equation 6-1
Equation 6-2
x (2N - R)]
x Z] Equation 6-3
/ N
/ N
/ N
and V are equal.
TTX TRX
165