Datasheet

SCEA019 - January 2001
Texas Instruments GTLP Frequently Asked Questions 7–115
Table 10. Bidirectional or Unidirectional B-to-A Voltage Translations
LV-CMOS Device GTLP Device
Supply Voltage
(V
CC
)
Threshold Set Point
(V
t
)
Set V
ref
To
2.5 V 1.25 V 1.9 V
1.8 V 0.9 V 1.2 V
1.5 V 0.75 V 0.9 V
1.2 V 0.6 V 0.6 V
1.0 V 0.5 V 0.5 V
0.8 V 0.4 V 0.4 V
Table 11 shows possible voltage-translation combinations and recommended GTLP device
V
ref
settings for the unidirectional B-to-A case where TI-OPC circuitry is inactive. Additionally,
since TI-OPC circuitry is not featured in the GTLP817, GTLPH16612, or any GTL devices, this
table also can be used in all cases.
Table 11. Unidirectional B-to-A Voltage Translations
LV-CMOS Device GTLP Device
Supply Voltage
(V
CC
)
Threshold Set Point
(V
t
)
Set V
ref
To
2.5 V 1.25 V 1.25 V
1.8 V 0.9 V 0.9 V
1.5 V 0.75 V 0.75 V
1.2 V 0.6 V 0.6 V
1.0 V 0.5 V 0.5 V
0.8 V 0.4 V 0.4 V
A pullup termination resistor is required only if operating in the A-to-B direction and can be
between 50 Ω to 1 kΩ, depending on the transition times needed for the circuit.
Normally, V
IH
and V
IL
are ±50 mV around V
ref
but expands to ±200 mV at 0.4 V as V
ref
is
reduced below 0.7 V.