AN2719 Freescale Semiconductor / Motorola, AN2719 Datasheet - Page 10

• Manufacturer Part Number: AN2719
• Description: A Transmitter Using Tango3 (Step-by-step Design for ISM Bands)
• Manufacturer: Freescale Semiconductor / Motorola

Tango3 RF Module
To achieve the wanted frequency shift of 100 kHz in FSK modulation, C5 should be omitted because of
the parasitic capacitance of the printed circuit board.
Some oscillation occurred between the PA and Tango3. The decoupling capacitors appear to be critical
and we reversed the value of C3 and C11 and increased C1 to 10nF.
The matching network has been optimized to have the maximum fundamental frequency level with
minimum harmonic level. The final values are:
How to Use the Tango3 RF Module
All the logic level signals available on J1 are referred to VCC and GND. Do not apply any signal higher
than VCC or lower than GND to the module.
10
–
–
–
–
–
C8 = 3.9 pF
L2 = 22 nH
C9 = 8.2 pF
L3 = 12 nH
C10 = 6.8 pF
VCC
R6
0
C6
10pF
X1
13.56MHz
R5
15k
1
2
3
4
5
6
7
Figure 7. Final Optimized Schematic Diagram
DATACLK
DATA
BAND
GND
XTAL1
XTAL0
REXT
U1
MC33493
ENABLE
GNDRF
RFOUT
MODE
CFSK
VCC
VCC
A Transmitter Using Tango3, Rev. 0
14
13
12
11
10
9
8
100pF
C3
C11
22nF
R2
220R
100pF
C2
C7
4.7nF
R1
10k
VCC
L1
100nH
Q1
BFR92
C1
10nF
C4
100pF
5.6pF
C8
L2
22nH
5.6pF
C9
Freescale Semiconductor
L3
12nH
6.8pF
C10
SMA v ert
J2