Microchip Technology 10-Pin MSOP, Руководство пользователя

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10-Pin MSOP and 8-Pin MSOP Evaluation Board User’s Guide
DS50002569A-page 20

2017 Microchip Technology Inc.
See Figure 2-6 to observe how to create an RC output filter by cutting the trace
between the two Pads for component RS6 and then installing the desired resistor at
that location. The capacitor is then installed at component RD6.
FIGURE 2-6: Creating an RC output filter
2.4.3 Passive Components - RUx, RDx, RSx, C1 and C2
The footprints for these components allow maximum flexibility in the use of this PCB to
evaluate a wide range of devices. The purpose of these components may vary depend-
ing on the device under evaluation and how it is to be used in the desired circuit. Refer
to the device data sheet for the recommended components that should be used when
evaluating that device.
• Component RUx allows a pull-up resistor to be installed for the device pin.
• Component RDx allows a pull-down resistor or a a capacitive load/filter to be
installed for the device pin.
• Component RSx allows a series component to be fitted.
• Component C1 and C2 allows power supply filtering capacitors to be installed.
2.4.4 Multiplexing Resistor R1
Due to the number of pins available in a specific package, some digital potentiometers
multiplex together the SDI and SDO signals. It is therefore necessary to connect the
two signal lines coming from the host to a single pin on the device. The digital potenti-
ometer needs a way to overdrive the host controller’s SDO signal.
Figure 2-7 shows an example connection, from the MCP45x1 data sheet. The R1 value
would need to be determined based on the V
IH
,V
IL
, V
OH
and V
OL
levels of the two
devices.
FIGURE 2-7: Multiplexed SDI/SDO Connection Example.