Si4840/44-DEMO
Si4840/44 D
EMO
B
OARD
U
SER
’
S
G
UIDE
1. Features
ATDD (analog tune and digital display) FM/AM/SW radio
Worldwide FM band support from 64 to 109 MHz with 5 default sub-bands:
FM1
FM2
FM3
FM4
FM5
87–108 MHz (Demo Board Default)
86.5–109 MHz
87.3–108.25 MHz
76–90 MHz
64–87 MHz (Demo Board Default)
520–1710 kHz (Demo Board Default)
522–1620 kHz(Demo Board Default)
504–1665 kHz
520–1730 kHz
510–1750 kHz
5.6–6.4 MHz (Demo Board Default, for Si4844 only)
5.95–6.2 MHz
6.8–7.6 MHz (Demo Board Default, for Si4844 only)
7.1–7.6 MHz
9.2–10 MHz (Demo Board Default, for Si4844 only)
9.2–9.9 MHz
11.45–12.25 MHz (Demo Board Default, for Si4844 only)
11.6–12.2 MHz
13.4–14.2 MHz (Demo Board Default, for Si4844 only)
13.57–13.87 MHz
15–15.9 MHz (Demo Board Default, for Si4844 only)
15.1–15.8 MHz
17.1–18 MHz (Demo Board Default, for Si4844 only)
17.48–17.9 MHz
21.2–22 MHz (Demo Board Default, for Si4844 only)
21.45–21.85 MHz
Worldwide AM band support from 504 to 1750 kHz with 5 default sub-bands:
AM1
AM2
AM3
AM4
AM5
Worldwide SW band support from 2.3 MHz to 28.5 MHz with 16 default sub-bands:
SW1
SW2
SW3
SW4
SW5
SW6
SW7
SW8
SW9
SW10
SW11
SW12
SW13
SW14
SW15
SW16
Twelve-position slide switch or one push button for selecting different bands according to the target application
Two AAA battery operations with working voltage down to 2.0 V
Economical potentiometer for frequency tuning replaces more expensive variable capacitor (PVC)
Potentiometer and/or push button volume control
FM 50 µs or 75 µs (default) de-emphasis
FM stereo indication threshold 6 dB separation at 20 dBµv RF input (default) or 12 dB separation at 28 dBµv RF
input
9-level Bass/Treble via push button control for FM
7-level Bass/Treble via push button control for AM/SW
FM/AM/SW band indicator and frequency display in LCD
2x4 matrix keypad
The frequency range of each band, the ST indication threshold, de-emphasis and AM channel space can be
reconfigured by host MCU.
Rev 0.1 8/11
Copyright © 2011 by Silicon Laboratories
Si4840/44-DEMO
Si4840/44-DEMO
2. Overview
This manual describes the operation of the Silicon Labs Si4840/44-DEMO board, Rev 1.3, June 30, 2011. The
Silicon Laboratories Si4840/44 DEMO board is designed with the 24-pin SSOP-packaged Si4840/44 chip, the
revolutionary single chip AM/FM/SW receiver that integrates everything from antenna output to audio input and
allows use of common and economical potentiometers to do the frequency tuning. It provides a complete portable
analog tune digital display AM/FM/SW radio design. The LCD displays the tuning information. The Si4840/44-
DEMO is designed with 1-layer PCB, allowing the lowest cost without sacrificing the RF performance. The demo
board works with two AAA batteries and working voltage down to 2.0 V.
3. Description
Figure 1 and Figure 2 show the physical layout of the board with key components indicated.
Figure 1. Si4840/44-DEMO Board Top Side in Time Mode
2
Rev 0.1
Si4840/44-DEMO
Figure 2. Si4840/44-DEMO Board Bottom Side
Power:
BAT1: 2 cells AAA battery compartment
Audio connectors:
J5: Stereo audio headphone output
Antenna selections:
AM antenna: Ferrite stick antenna for AM
J6: SMA connector for AM conductive test
S11: AM antenna selection
1
2
3
1-2: SMA for AM Conductive Test (J6)
2-3: AM ferrite antenna
J1: BNC connector for FM/SW conductive test or FM whip antenna
Rev 0.1
3
Si4840/44-DEMO
S12: FM antenna selection
1
2
3
1-2 BNC (J1)
2-3 HP ANT (J5)
Radio Band selection:
The Demo board provides 2 methods to select the radio band. One is to use the slide switch (S2); the other is to
use the POWER/BAND push button. S14 determines which method is in use.
S14:
3
2
1
2-3: Use slide switch to select band
1-2: Use push button to select band
Radio Band Property setting:
S13:
1
2
3
1-2: Use the keypad to set the band property via MCU
2-3: Use the tuner default band setting values
4
Rev 0.1
Si4840/44-DEMO
Audio output test point:
For general specification test, TP3 is the recommended audio signal test point. The audio test instrument should
be connected to TP3 to get more accurate test results. J5 can also be used as an audio test point, but the test
results may not be entirely accurate under some circumstances.
TP3:
1
2
3
GND
Lout
Rout
Main components:
U1: Silicon Laboratories Si484x FM/AM/SW ATDD tuner
U2: Audio amplifier
U3: MCU
LCD: The digital display of tuning information
Control interface:
VR1: Frequency tuning wheel
VR2: Volume control wheel
S3~S10: The keypad for human interface
S2: Band slide switch for FM, AM, and SW
1
2
3
4
5
6
7
8
9
10
11
12
Band definition:
1: FM1 (87–108 MHz), De-emphasis=75 us, ST indication=6 dB separation@20 dBµV
2: FM5 (64–87 MHz), De-emphasis=75 us, ST indication=6 dB separation@20 dBµV
3: AM1 (520–1710 kHz), 10 kHz spacing
4: AM2 (522–1620 kHz), 9 kHz spacing
5: SW1 (5.6–6.4 MHz)
6: SW3 (6.8–7.6 MHz)
7: SW5 (9.2–10.0 MHz)
8: SW7 (11.45–12.25 MHz)
9: SW9 (13.4–14.2 MHz)
10: SW11 (15–15.9 MHz)
11: SW13 (17.1–18 MHz)
12: SW15 (21.2–22 MHz)
Rev 0.1
5
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