Datasheet

SCBA015A
7–29
Fast GTLP Backplanes With the GTLPH1655
8
7
6
5
4
3
2
1
0
–1
Voltage – V
V
OH
@ V
REF
= 1.5 V
V
OH
@ V
REF
= 1.0 V
V
OH
@ V
REF
= 0.5 V
V
OH
@ V
REF
= 0 V
V
OFF
@ V
REF
= 0 . . . 1.5 V
V
OH
@ V
REF
= 0 . . . 1.5 V
V
OL
@ V
REF
= 0 . . . 1.5 V
Current – mA
–100 –80 –60 –40 –20 0 20 40 60 80 100
SN74GTLPH1655 Output Characteristics, Static High, Low, and Off State
Figure 19. Output Characteristics of GTLP Port of SN74GTLPH1655
In the high state, the output transistor is blocking up to V
REF
+ one diode forward voltage. Thus,
the output is at a very high resistance, as shown in Figure 19. Above V
REF
+ 0.7 V, a low
resistive part follows, and then a high-resistive section, up to 7 V. Above 7 V, the curve again
shows diode behavior. The special curve of output characteristics is caused by implementation
of the TI-OPC into the GTLP outputs.
Because of the bidirectionality of the SN74GTLPH1655, the input protection diode also can be
seen at the output during off state (for V
CC
= 0 V) and 3-state. The outputs and inputs of the
device are connected together and routed to a single pin.