Microchip Technology RN4870-I/RM128, Руководство пользователя, Страница: 24 / 55

2016-2021 Microchip Technology Inc. DS50002489E-page 21
RN4870/71
4.4 RN4871U Module
Figure 4-10 shows the physical dimensions of the
RN4871U module. Figure 4-11 illustrates the recom-
mended PCB layout. It is highly recommended to lay
out the host PCB as suggested in
Figure 4-12 .
Figure 4-13 shows the recommended placement for
the module on the host PCB board. For optimal
transmission and reception sensitivity, place the
module at the edge of the board.
A low-impedance ground plane ensures the best radio
performance (best range, lowest noise). Pin 1 (BT_RF)
is a 50 Ohm connection that can be connected to an
external antenna, such as a PCB trace antenna, a
component (chip) antenna or through a host PCB
50 Ohm microstrip trace. This trace can be extended to
include passive parts for antenna attenuation padding,
impedance matching or to provide test posts. It is
recommended that the microstrip trace to be as short
as possible for minimum loss and best impedance
matching. If the microstrip trace is longer, a 50 Ohm
impedance is recommended.
FIGURE 4-10: RN4871U MODULE DIMENSIONS
Top View
Bottom View Side View