Datasheet

SCEA019 - January 2001
Texas Instruments GTLP Frequently Asked Questions 7–81
GTL devices are bidirectional translators (see Figure 2). A-Port (daughter-card side) input can
be 5-V CMOS, TTL, or LVTTL logic levels; output is LVTTL, which is compatible with TTL
logic levels. B-Port (backplane side) input and output is GTL or GTL+ signal levels.
Figure 2. GTL Bidirectional Translator
5V TTL
1.5
0GND
2.4
2.0
0.4
0.8
5 V
V
V
OH
V
IH
V
t
V
IL
V
OL
LVTTL
1.5
0
GND
2.4
0.4
3.3 V
0.8
2.0
V
CC
V
OH
V
IH
V
t
V
IL
V
OL
V
IH
V
OH
5V CMOS
4.44
3.5
2.5
1.5
0.5
0
5 V V
CC
GND
V
t
V
IL
V
OL
Input
Input/Output
Daughter-Card Side
0.8
1.2 V
0.4
0.75
0.85
V
t
, V
ref
V
OH
, V
TT
V
IH
V
IL
V
OL
1
1.5 V
0.55
0.95
1.05
V
IL
V
OH
, V
TT
V
IH
V
t
, V
ref
V
OL
GTL GTL+
Input/Output
Backplane Side