SI4031-B1-FM Silicon Laboratories Inc, SI4031-B1-FM Datasheet - Page 27

• Manufacturer Part Number: SI4031-B1-FM
• Description: IC TX 240-930MHZ -8-13DB 20VQFN
• Manufacturer: Silicon Laboratories Inc
• Type: ISM Transmitterr

Specifications of SI4031-B1-FM

• Package / Case: 20-VQFN
• Frequency: 240MHz ~ 930MHz
• Applications: General Purpose
• Modulation Or Protocol: FSK, GFSK, OOK
• Data Rate - Maximum: 256 kbps
• Power - Output: 13dBm
• Current - Transmitting: 30mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 1.8 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Operating Frequency: 240 MHz to 930 MHz
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 1.8 V to 3.6 V
• Supply Current: 30 mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

4. Modulation Options
4.1. Modulation Type
The Si4030/31/32 supports three different modulation options: Gaussian Frequency Shift Keying (GFSK),
Frequency Shift Keying (FSK), and On-Off Keying (OOK). GFSK is the recommended modulation type as it
provides the best performance and cleanest modulation spectrum. Figure 8 demonstrates the difference between
FSK and GFSK for a Data Rate of 64 kbps. The time domain plots demonstrate the effects of the Gaussian filtering.
The frequency domain plots demonstrate the spectral benefit of GFSK over FSK. The type of modulation is
selected with the modtyp[1:0] bits in "Register 71h. Modulation Mode Control 2." Note that it is also possible to
obtain an unmodulated carrier signal by setting modtyp[1:0] = 00.
TX Modulation Time Domain Waveforms -- FSK vs. GFSK
-0.5
-1.0
-1.5
-0.5
-1.0
1.5
1.0
0.5
0.0
1.0
0.5
0.0
0
50
100
modtyp[1:0]
150
200
00
01
10
11
time, usec
250
300
Figure 8. FSK vs. GFSK Spectrums
GFSK (enable TX Data CLK when direct mode is used)
350
400
450
500
Rev 1.1
Unmodulated Carrier
Modulation Source
-100
-100
TX Modulation Spectrum -- FSK vs GFSK (Continuous PRBS)
-20
-40
-60
-80
-20
-40
-60
-80
-250
OOK
FSK
DataRate
-200
64000.0
-150
-100
TxDev
Si4030/31/32-B1
32000.0
-50
freq, KHz
0
BT_Filter
50
0.5
100
ModIndex
150
1.0
200
250
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