12-bit GTL to LVTTL translator with power good control and
high-impedance LVTTL and GTL outputs
Rev. 02 — 26 September 2006
Product data sheet
1. General description
The GTL2008/GTL2107 is a customized translator between dual Xeon processors,
Platform Health Management, South Bridge and Power Supply LVTTL and GTL signals.
Functionally and footprint identical to the GTL2007, the GTL2008/GTL2107 LVTTL and
GTL outputs were changed to put them into a high-impedance state when EN1 and EN2
are LOW, with the exception of 11BO because its normal state is LOW, so it is forced
LOW. EN1 and EN2 will remain LOW until VCC is at normal voltage, the other inputs are in
valid states and VREF is at its proper voltage to assure that the outputs will remain
high-impedance through power-up.
Both the GTL2008/GTL2107 and the GTL2007 are derived from the GTL2006. They add
an enable function that disables the error output to the monitoring agent for platforms that
monitor the individual error conditions from each processor. This enable function can be
used so that false error conditions are not passed to the monitoring agent when the
system is unexpectedly powered down. This unexpected power-down could be from a
power supply overload, a CPU thermal trip, or some other event of which the monitoring
agent is unaware.
A typical implementation would be to connect each enable line to the system power good
signal or the individual enables to the VRD power good for each processor.
Typically Xeon processors specify a VTT of 1.1 V to 1.2 V, as well as a nominal Vref of
0.73 V to 0.76 V. To allow for future voltage level changes that may extend Vref to 0.63 of
VTT (minimum of 0.693 V with VTT of 1.1 V) the GTL2008/GTL2107 allows a minimum Vref
of 0.66 V. Characterization results show that there is little DC or AC performance variation
between these levels.
The GTL2008 is the companion chip to the GTL2009 3-bit GTL Front-Side Bus frequency
comparator that is used in dual-processor Xeon applications.
The GTL2107 is the Intel designation for the GTL2008.
I Operates as a GTL to LVTTL sampling receiver or LVTTL to GTL driver
I EN1 and EN2 disable error output
I All LVTTL and GTL outputs are put in a high-impedance state when EN1 and EN2 are
I 3.0 V to 3.6 V operation
I LVTTL I/O not 5 V tolerant
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