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AR# 17102

Spartan-3/-3E - Can VCCO be either 2.5V or 3.3V for banks that power configuration pins?

Description

General Description:

Can VCCO be either 2.5V or 3.3V during configuration for banks that power configuration pins?

Solution

Spartan-3

VCCO for dual-purpose pins in banks 4 and 5 can be either 2.5V or 3.3V. During configuration, the dual-purpose pins default to the CMOS input and output levels for the associated VCCO voltage supply. The dedicated configuration pins and JTAG pins are powered by VCCAUX, which is always 2.5V. You cannot power the dedicated configuration pins or JTAG pins at 3.3V without a current limiting resistor because the upper clamp diode will turn on, and the current must be kept under 10mA.

NOTE: Configuration has not yet been tested with VCCO banks 4 and 5 powered at 1.8V. Consequently, the default CMOS input and output levels have not been characterized.

For more information on configuration in a 3.3V environment, see (Xilinx Answer 20477).

The Spartan-3 functional description data sheets can be found at:

http://www.xilinx.com/xlnx/xweb/xil_publications_display.jsp?category=/Data+Sheets/FPGA+Device+Families&iLanguageID=1

Spartan-3E

VCCO for dual-purpose pins in banks 1 and 2 can be either 1.8V, 2.5V or 3.3V. During configuration, the dual-purpose pins default to the CMOS input and output levels for the associated VCCO voltage supply. The dedicated configuration pins and JTAG pins are powered by VCCAUX, which is always 2.5V. You cannot power the dedicated configuration pins or JTAG pins at 3.3V without a current limiting resistor because the upper clamp diode will turn on, and the current must be kept under 10mA.

For more information on configuration in a 3.3V environment, see (Xilinx Answer 20477).

The Spartan-3E functional description data sheets can be found at:

http://www.support.xilinx.com/xlnx/xweb/xil_publications_display.jsp?sGlobalNavPick=&sSecondaryNavPick=&category=-1211389&iLanguageID=1

AR# 17102
Date Created 09/03/2007
Last Updated 12/15/2012
Status Active
Type General Article