17.0 Application Notes
The different possibilities to power supply the LMX9838 de-
pend on the IO interface logic level.
Figure 9 represents an example of system functional
schematic for the LMX9838 using a 3.0V to 3.3V IO interface.
Figure 10 represents an example of system functional
schematic for the LMX9838 using a 2.5V to 3.0V IO interface.
Figure 11 represents an example of system functional
schematic for the LMX9838 using a 1.8V to 2.5V IO interface.
Figure 12 represents an example of system functional
schematic for the LMX9838 using a 1.8V IO interface.
17.1 FILTERED POWER SUPPLY
It is important to provide the LMX9838 with adequate ground
planes and a filtered power supply. It is highly recommended
that a 2.2
μ
F and a 100 nF bypass capacitor be placed as
close as possible to the power supply pins V
CC
, MV
CC
, and
V
CC
_IO.
17.2 FREQUENCY AND BAUDRATE SELECTION
OP3, OP4, OP5 can be strapped to the host logic 0 and 1
levels to set the host interface boot-up configuration. Alterna-
tively all OP3, OP4, OP5 can be hardwired over 1k Ohm
pullup/pulldown resistors. See Table 7.
30027908
Notes:
Capacitor values C1 and C2 may vary depending on design and crystal manufacturer specification.
FIGURE 9. 3.0V to 3.3V Example Functional System Schematic
23
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LMX9838
