12.
Application Reference Design
This section shows the ATSAMR30M18A module application schematics for different supported host interfaces. It
is required to add 100Ω series resistors for module pins 3, 4, 6, 17, 19 and 20 to minimize radiated emission from
the open-ended connectors/traces. Place these resistors (R101, R102, R103, R104, R105 and R106) as close as
possible to the specific module pin in the PCB layout. If any of these module pins (3, 4, 6, 17, 19 and 20) are left
unused in the design, it is recommended these pins be terminated through a 10 kΩ resistor to GND. Additionally,
drive the pins to logic low during the firmware initialization.
Figure 12-1. Application Reference Design
10uF
C103
VCC_P3V3
GND
PA
06
_A
IN
_6
PA
07
_G
P
IO
PA
31
_S
W
D
IO
PA
30
_S
W
C
L
K
PA
09
_I
2C
_S
C
L
PA
08
_I
2C
_S
D
A
PA28_GPIO
PA27_SPI_SS
PA
24
_U
A
R
T
_T
X
_U
SB
_D
M
PA
25
_U
A
R
T
_R
X
_U
SB
_D
P
PA
15
_U
A
R
T
_R
X
PA
16
_S
P
I_
M
IS
O
PA18_SPI_MOSI
RF_OUT
RF Frontend
GND
GND
GND
PA
14
_U
A
R
T
_T
X
R
E
SE
T
i
PCB Rule 50 Ohm PCB Trace
FEED POINT
1
NC
2
0900AT43A0070
A101
ANT_SUB_GHZ
Trace Element
5.6nH
L103
100n
C104
VCC
12
G
N
D
5
R
E
SE
T
14
PA
09
20
PA
14
3
PA
08
19
PA
15
4
PA
24
1
GND
13
PA18
8
PA
25
2
PA
16
6
PA
17
7
GND
24
PA
07
18
PA19
9
PA27
10
PA28
11
PA
30
15
PA
31
16
RF OUT
23
PA
06
17
GND
22
GND
21
GND
25
U101
SAMR30 Module
7.5nH
L101
INDUCTOR
3.3nH
L102
INDUCTOR
1.5nH
L104
12pF
C101
12pF
C102
GND
10
0R
R
10
6
10
0R
R
10
5
10
0R
R
10
4
10
0R
R
10
1
10
0R
R
10
2
10
0R
R
10
3
PA
17
_S
P
I_
SS
PA19_SPI_SCK
GND
GND
DNP
DNP
12.1
RF Trace Layout Design Instructions
The ATSAMR30M18A module transmitter is certified with:
1.
SMA
(1)
connector and micro strip layout
2.
On-board chip antenna and micro strip layout
3.
On-board PCB antenna and micro strip layout
Note:
1.
If the host board of ATSAMR30M18A is designed to have an antenna port that is accessible to the end user,
an RP (Reverse Polarity)-SMA socket must be used. If an RF coaxial cable is used between the module RF
output and the enclosure, an RP-SMA connector must be used in the enclosure wall for interface with antenna.
ATSAMR30M18A
Application Reference Design
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2018-2021 Microchip Technology Inc.
and its subsidiaries
Datasheet
DS70005384B-page 44