SI4720-B20 Datasheet, PDF (19/48 Pages) Silicon Laboratories – BROADCAST FM RADIO TRANSCEIVER FOR PORTABLE APPLICATIONS

Si4720/21-B20
2. Test Circuit
2.1. Test Circuit Schematic
FMI
TX Antenna
2 pF
VTXOUT
50 
C4
L1
120 nH
R1
V_IO
1 _NC
2 _FMI
3 _RFGND
4 _TXO
5 _RST
U1
Si4720/21
C2
0.47 µF
C3
RIN ^{15 0.47 µF}
LOUT ¹⁴
ROUT ¹³
GND ¹²
VDD ¹¹
C1
22 nF
LIN
RIN
LOUT
ROUT
VBATTERY
2.7 to 5.5 V
RST
SEN
SCLK
SDIO
RCLK
VIO
1.5 to 3.6 V
X1
RCLK
C5
C6
Notes:
1. Si4720/21 is shown configured in I²C compatible bus mode.
2. GPO2/INT can be configured for interrupts with the powerup command.
3. To ensure proper operation and FM transmitter performance, follow the guidelines in
“AN383: 3 mm x 3 mm QFN Universal Layout Guide.”
Silicon Laboratories will evaluate schematics and layouts for qualified customers.
4. LIN, RIN line inputs must be ac-coupled.
Figure 10. Test Circuit Schematic
2.2. Test Circuit Bill of Materials
Component(s)
C1
C2, C3
C4
C5, C6
L1
R1
X1
U1
Table 14. Si4720/21 Test Circuit Bill of Materials
Value/Description
Supply bypass capacitor, 22 nF, 20%, Z5U/X7R
AC Coupling Capacitor, 0.47 µF
2 pF, ±.05 pF, 06035JZR0AB
Crystal load capacitors, 22 pF, ±5%, COG
(Optional: for crystal oscillator option)
120 nH inductor, Qmin = 30
49.9 , 5%
32.768 kHz crystal (Optional: for crystal oscillator option)
Si4720/21 FM Radio Transceiver
Supplier(s)
Murata
Murata
AVX
Venkel
Murata
Murata
Epson
Silicon Laboratories
Rev. 1.0
19