
Si4311-DB
Si4311 DEMO BOARD USER ’S GUIDE
1. Overview
The Silicon Laboratories Si4311-DEMO board provides a complete FSK radio design with numerous selectable
features that demonstrate the capabilities of the Silicon Laboratories Si4311 FSK receiver. The Si4311-DEMO
board can be configured to receive FSK data from an SMA connector or wirelessly with an onboard printed circuit
board (PCB) antenna. The demodulated output data from the Si4311-DEMO board can be measured via an SMA
connector and/or observed with an LED and/or heard with an audio buzzer. The system is powered by a 9 V
battery or an external 3.3 V power supply.
2. Features
Single chip FSK receiver
Selectable 315/433.92 MHz carrier frequency
Selectable data rate, frequency deviation
3. Description
Figures 1 and 2 show the physical layout of the board with key components indicated.
Figure 1. Si4311 DEMO Boa r d Top Side
Rev. 0.3 9/09 Copyright © 2009 by Silicon Laboratories Si4311-DB

Si4311-DB
Figure 2. Si4311 DEMO Board Bottom Side with 9 V Battery
Power Supply Connector
J1: Jumper to select external 3.3 V supply. This is a solderable jumper and should be shorted when used.
J7: External 3.3 V supply connector: +3.3 V with the jumper on the right side and GND on the left side.
J3: 9 V battery supply connector: Power on with the jumper on the right side and power off with the jumper on the
left side.
J8: Jumper used to measure Si4311 current consumption.
Jumper connected (shorted) is normal operation.
Jumper connected with an ammeter in series to measure current.
D3: Power-on indicator. LED lights up when powered on.
RF Input
J4: SMA connector for an external RF input. Ensure inductor L3 is open to remove the PCB antenna when using
the SMA input.
Demodulated Data Output
J5: SMA connector for demodulated data output.
External Clock Driver
J9/J17: These solder jumpers should be shorted when an external clo ck driver is used.
J10: External clock connection point.
Automatic Frequency Centering (AFC)
J11: Jumper used to select AFC function.
Logic High (left side connection) to enable AFC.
Logic Low (right side connection) to disable AFC.
Carrier Frequency Selection
J12: Jumper used to select 315 or 433.92 MHz carrier frequency.
Logic High (left side connection) for 315 MHz.
Logic Low (right side connection) for 433.92 MHz.
2 Rev. 0.3

Bit Time Selection
J13/J14: Two jumpers used for bit time selection.
Table 1. Bit Time Selection
J13 J14 Bit Time [µs]
0 0 1000
01 500
10 200
11 100
Frequency Deviation Selection
J15/J16: Two jumpers used for frequency deviation selection.
Table 2. Frequency Deviation Selection
J13 J14 Frequency Deviation [kHz]
00 30
01 50
Si4311-DB
10 70
11 90
Key Components
U4: Si4311 single chip FSK receiver.
X1: 16 MHz crystal.
D1: LED lights up when data output present.
B2: Audio buzzer sounds when data output is present.
Rev. 0.3 3

Si4311-DB
4. Schematic
Figure 3. Si4311-DEMO Schematic
4 Rev. 0.3