Datasheet
SCEA019 - January 2001
Texas Instruments GTLP Frequently Asked Questions 7–95
14 What is the maximum data throughput using GTLP?
Data throughput is a function of clock frequency times the bit width of the backplane.
Increasing the maximum frequency or backplane bit width increases data throughput. GTLP
devices can operate at speeds up to 175 MHz into a distributed load with good signal integrity.
A 32-bit backplane operating at 110-MHz clock frequency has a data transfer rate of
1.76 Gbit/s in single-edge latched-mode (data is transferred at one-half the clock frequency)
applications to 7 Gbit/s in dual-edge transparent-mode applications.
Data throughput in GTLP backplanes is now limited by timing requirements, not signal
integrity, as in past backplane devices. Maximum frequency is a function of device maximum
propagation delay (t
pd
), pin-to-pin skew, backplane construction or length, and how the clock
is distributed (see Figure 13).
50
65
80
95
110
0 6 12 18
Backplane Length - inches
Maximum Backplane Frequency - MHz
Source Synchronous - Fast Edge
Synchronous - Microstrip - Fast Edge
Synchronous - Stripline - Fast Edge
Source Synchronous - Slow Edge
Synchronous - Microstrip - Slow Edge
Synchronous - Stripline - Slow Edge
Figure 13. Maximum Backplane Frequency
5.5 ns max t
pd
7 ns max t
pd