ATA5771_09 ATMEL [ATMEL Corporation], ATA5771_09 Datasheet - Page 33

• Manufacturer Part Number: ATA5771_09
• Description: Microcontroller with UHF ASK/FSK Transmitter
• Manufacturer: ATMEL [ATMEL Corporation]

4.4
6
Application Circuit
T5753
Figure 4-2.
Note:
For the blocking of the supply voltage a capacitor value of C
(see
antenna to the power amplifier where C
(18 pF + 27 pF in series); for C
erance value and to have the possibility to realize the Z
capacitors.
C
suppresses the 1
best suppression is achieved when C
ANT2.
The loop antenna should not exceed a width of 1.5 mm, otherwise the Q-factor of the loop
antenna is too high.
L
load resonance frequency of the crystal. Normally, a value of 12 pF results for a 15 pF
load-capacitance crystal.
1
1
([50 nH to 100 nH) can be printed on PCB. C
forms together with the pins of T5753 and the PCB board wires a series resonance loop that
Figure 4-3 on page 7
For 345 MHz C
Output Power Measurement at f = 315 MHz
st
harmonic, hence the position of C
2
ANT1
ANT2
has to be changed to 2.7 pF
and
Z
2
Lopt
Figure 4-4 on page
two capacitors in series should be used to achieve a better tol-
V
L
S
1
56 nH
3.3 pF
1
1 nF
is placed as close as possible to the pins ANT1 and
C
C
1
2
1
typically is 22 pF/NP0 and C
4
should be selected that the XTO runs on the
Z = 50
8). C
1
on the PCB is important. Normally the
1
and C
Load,opt
3
= 68 nF/X7R is recommended
Power
meter
2
50
R
are used to match the loop
by using standard valued
in
2
is 10.8 pF/NP0
4510J–RKE–12/08