ATAB8402 Atmel, ATAB8402 Datasheet - Page 5

• Manufacturer Part Number: ATAB8402
• Description: BOARD DEMO 433MHZ RF TRANSMITTER
• Manufacturer: Atmel
• Type: Transmitterr

Specifications of ATAB8402

• Frequency: 433MHz
• Wireless Frequency: 315 MHz
• Modulation: ASK, FSK
• For Use With/related Products: ATA8402
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Figure 2-4.
9115A–INDCO–01/08
PA
C
PA_Out
Matching Loop Antenna to the Power Amplifier
ANT1
ANT2
The parallel resonance impedance (Z
The variable r in the equation 9 describes the transformation ratio of the matching structure
(C
In order to get lower influences of the capacitor's tolerance and to achieve an optimal matching
with standard elements, two capacitor are used in series for C
placed as close as possible to the IC to suppress the first harmonic. The connection of the pin
ANT2 to ground must be designed properly. The best practical way is to place several vias direct
to the ground plane of the board. This rule of ground connection is also valid for the ground con-
nection of the matching elements.
If a higher harmonic rejection is needed, an additional low-pass filter has to be designed
between the loop antenna and the transmitter.
matic. The Cx must be placed as close as possible to the power amplifier output.
Z
Z
C
r
C
Choke
II
II
II
match2
=
Z
RF
match1,2
load
=
=
=
----------------------------------------------------------------------------- -
C
Q
r
----------------- -
2
match1
2
loop
Z
L
=
1
load
).
loop
C
---------------------------------------------- -
C
C
2 fL
match2
match1
match1
+
=
C
C
loop
PA_Out
----------------------------------------------------------------------------- -
match2
C
r 1
C
+
–
match1
Z
match1
C
II
PA_Out
+
Equation 8
Equation 9
+
C
+
R
R
C
Loop
match2
C
loss
rad
PA_Out
PA_Out
Equation 12
C
+
C
match1
C
match2
match2
||
) can be calculated by equation 8.
=
ATA8401/ATA8402/ATA8403
r
PA
C
C
II
Equation 10
PA_Out
Figure 2-5 on page 6
–
C
PA_Out
ANT1
ANT2
V
Choke
Equation 11
S
RF
C
match2
match1
shows the principle sche-
. The C
C
II
C
match2
Loop Antenna
match1
has to be
5