Answers Database
LogiCORE PCI32 4000: XC4000XLT Clamp (Vtt) diode specification
Record #3544
Product Family: Documentation
Product Line: PCI Apps
Product Part: PCI Frequently Asked Questions
Problem Title:
LogiCORE PCI32 4000: XC4000XLT Clamp (Vtt) diode specification
Problem Description:
Priority: Standard
Problem Description:
The clamp diodes present in the XLT IOB's are required to
sink and source a certain amount of current at fixed Vcc
in order to be PCI compliant.
Solution 1:
The Vtt pins on the XLT devices are all connected together by
a bus that goes to all the I/O's. It is still important to
connect all Vtt pins to the same voltage source.
Solution 2:
The diodes are fully compliant and meet the following
requirements in the PCI compliance checklist:
CE31: The clamps on all signals source at least 25mA
at -1V, and 91 mA at -2V.
CE32: The clamps on all signals sink at least 25mA
at Vcc=+1V, and 91 mA at Vcc=+2V.
End of Record #3544 - Last Modified: 10/01/99 14:41 |
