mc13202 Freescale Semiconductor, Inc, mc13202 Datasheet - Page 28

• Manufacturer Part Number: mc13202
• Description: Mc13203 2.4ghz Rf Transceiver For Zigbee Applications
• Manufacturer: Freescale Semiconductor, Inc

9.4
Figure 16
F antenna is used for low cost. Only the RFIN port of the MC13202 is required because the differential
port is bi-directional and uses the on-chip T/R switch. Matching to near 50 Ohms is accomplished with L1,
L2, L3, and the traces on the PCB. A balun transforms the differential signal to single-ended to interface
with the F antenna.
The proper DC bias to the RFIN_x (PAO_x) pins is provided through the balun. The CT_Bias pin provides
the proper bias voltage point to the balun depending on operation, that is, CT_Bias is at VDDA voltage for
transmit and is at ground for receive. CT_Bias is switched between these two voltages based on the
operation. Capacitor C2 provides some high frequency bypass to the DC bias point. The L3/C1 network
provides a simple bandpass filter to limit out-of-band harmonics from the transmitter.
28
U5
MC1320x
RFIN_M
CT_Bias
RFIN_P
PAO_M
PAO_P
RF Single Port Application with an F Antenna
shows a typical single port RF application in which part count is minimized and a printed copper
6
5
2
1
3
Hibernate
Hibernate
Mode
Doze
Doze
Idle
Idle
Off
TX
TX
L1
1.8nH
L4
1.8nH
Table 11. CT_Bias Output vs. Register Settings (continued)
Figure 16. RF Single Port Application with an F-Antenna
CT_Bias_en
L2
6.8nH
X
1
0
1
0
1
0
1
0
MC13202 Technical Data, Rev. 1.2
C2
10pF
3
2
4
Z1
LDB212G4005C-001
RF_switch_mode
1
5
6
X
X
X
X
X
X
X
X
0
L3
3.9nH
CT_Bias_inv
C1
1.0pF
X
X
X
X
X
X
X
X
1
0
Hi-Z
0
Hi-Z
0
Hi-Z
0 (Low-Z)
Hi-Z
Unknown
R2
0R
Not Mounted
CT_Bias
R1
0R
Freescale Semiconductor
2
3
4
5
ANT1
F_Antenna
J1
SMA_edge_Receptac