R

Power Regulation

The FPGA can drive VMARGIN_DN_xxxx_N and VMARGIN_UP_xxxx_N signals, where

xxxxindicates one of the six main power regulators: SSTL2, HSTL, SSTL18, VCC1V0, VCC2V5, and VCC3V3.

Table 3-16:Manual Voltage Margining

VMARGIN_UP_N

VMARGIN_DN_N

Output Voltage

 

 

 

High

High

Nominal

 

 

 

High

Low

-5%

 

 

 

Low

High

+5%

 

 

 

Low

Low

Not Applicable

 

 

 

If both voltage-margining inputs to the power regulator are pulled Low, the output voltage is close to nominal but has the possibility of a slightly higher error in the output voltage. The power modules use a low-leakage open-draincontrol signal to control the voltage margining. In the FPGA, this can be approximated by using a control signal that drives the output Low when active and does not drive the signal at all when inactive (high- impedance output).

Three-pin headers are available for performing manual voltage margining, using jumpers to select between Nominal, -5%, and +5%. Table 3-17shows the jumper settings.

Table 3-17:FPGA #1 Signals and On-Board Jumpers for Voltage Margining

Power Regulator

Signal Name

Jumper Setting

 

 

 

VCCINT (VR6)

VMARGIN_UP_VCC1V0_N

P48: 1 -> 2

 

VMARGIN_DN_VCC1V0_N

P48: 3 -> 2

 

 

 

SSTL18 (VR1)

VMARGIN_UP_SSTL18_N

P4: 1 -> 2

 

 

 

 

VMARGIN_DN_SSTL18_N

P4: 3 -> 2

 

 

 

SSTL2 (VR9)

VMARGIN_UP_SSTL2_N

P450 1 -> 2

 

 

 

 

VMARGIN_DN_SSTL2_N

P50: 3 -> 2

 

 

 

HSTL (VR10)

VMARGIN_UP_HSTL_N

P58: 1 -> 2

 

 

 

 

VMARGIN_DN_HSTL_N

P58: 3 -> 2

 

 

 

VCCAUX (VR12)

VMARGIN_UP_VCC2V5_N

P69: 1 -> 2

 

VMARGIN_DN_VCC2V5_N

P69: 3 -> 2

 

 

 

The TI PTH05010-WAZ and TI PTH05000-ADJ regulator outputs can be enabled or inhibited through the use of on-board two-pin jumpers. The inhibit jumpers use the following conventions:

Jumper OFF = Enabled

Jumper ON = Inhibited

Virtex-5 FPGA ML561 User Guide

www.xilinx.com

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UG199 (v1.2) April 19, 2008

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Xilinx ML561 manual 16Manual Voltage Margining, Output Voltage