Datasheet

SCEA019 - January 2001
Texas Instruments GTLP Frequently Asked Questions 7–79
4 If I use a parallel single-ended backplane, why do I need to use
backplane-optimized transceivers and not just typical LVT or FCT
devices?
The physics involved with a distributed-capacitance load limits the maximum frequency,
unless the device is optimized with slower edge rates that ring less in these environments.
FCT or LVT can offer only up to about 25 MHz, and, even then, signal integrity might be poor.
The new VME and GTLP families are optimized with slower edge rates and provide much
better signal integrity in a backplane environment. VME devices can operate up to about 40
MHz and are compatible with existing TTL/LVTTL backplane logic. GTLP is a derivative of
GTL, and can operate at up to 175 MHz.
5 What is VME?
VME is short for VERSA bus architecture and owes its heritage to the Motorola 6800
microprocessor. It is a standardized 21-slot, 64-bit backplane architecture, coordinated and
controlled by the VMEbus International Trade Association (VITA). TI is working with VITA on
the SN74VMEH22501, a new backplane-optimized device that supports the 2eVME and
2eSST protocols. More information on VITA can be obtained at http://www.vita.com. More
information on the new VME device can be obtained at http://www.ti.com/sc/etl.