SI4430-B1-FM Silicon Laboratories Inc, SI4430-B1-FM Datasheet - Page 37

• Manufacturer Part Number: SI4430-B1-FM
• Description: IC TXRX 900-960MHZ -8-13DB 20QFN
• Manufacturer: Silicon Laboratories Inc

Specifications of SI4430-B1-FM

• Package / Case: 20-VQFN
• Mfg Application Notes: Transitioning SI4430/31 to Rev B
• Frequency: 900MHz ~ 960MHz
• Data Rate - Maximum: 256kbps
• Modulation Or Protocol: ISM
• Applications: General Purpose
• Power - Output: 13dBm
• Sensitivity: -121dBm
• Voltage - Supply: 1.8 V ~ 3.6 V
• Current - Receiving: 18.5mA
• Current - Transmitting: 30mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Wireless Frequency: 900 MHz to 960 MHz
• Output Power: 13 dBm
• Operating Supply Voltage: 1.8 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Maximum Supply Current: 30 mA
• Minimum Operating Temperature: - 40 C
• Modulation: FSK, GFSK, OOK
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

5. Internal Functional Blocks
This section provides an overview some of the key blocks of the internal radio architecture.
5.1. RX LNA
Depending on the part, the input frequency range for the LNA is between 240–960 MHz. The LNA provides gain
with a noise figure low enough to suppress the noise of the following stages. The LNA has one step of gain control
which is controlled by the analog gain control (AGC) algorithm. The AGC algorithm adjusts the gain of the LNA and
PGA so the receiver can handle signal levels from sensitivity to +5 dBm with optimal performance.
In the Si4431, the TX and RX may be tied directly. See the TX/RX direct-tie reference design available on the
Silicon Labs
be set.
5.2. RX I-Q Mixer
The output of the LNA is fed internally to the input of the receive mixer. The receive mixer is implemented as an I-Q
mixer that provides both I and Q channel outputs to the programmable gain amplifier. The mixer consists of two
double-balanced mixers whose RF inputs are driven in parallel, local oscillator (LO) inputs are driven in quadrature,
and separate I and Q Intermediate Frequency (IF) outputs drive the programmable gain amplifier. The receive LO
signal is supplied by an integrated VCO and PLL synthesizer operating between 240–960 MHz. The necessary
quadrature LO signals are derived from the divider at the VCO output.
5.3. Programmable Gain Amplifier
The programmable gain amplifier (PGA) provides the necessary gain to boost the signal level into the dynamic
range of the ADC. The PGA must also have enough gain switching to allow for large input signals to ensure a
linear RSSI range up to –20 dBm. The PGA has steps of 3 dB which are controlled by the AGC algorithm in the
digital modem.
5.4. ADC
The amplified IQ IF signals are digitized using an Analog-to-Digital Converter (ADC), which allows for low current
consumption and high dynamic range. The bandpass response of the ADC provides exceptional rejection of out of
band blockers.
5.5. Digital Modem
Using high-performance ADCs allows channel filtering, image rejection, and demodulation to be performed in the
digital domain, resulting in reduced area while increasing flexibility. The digital modem performs the following
functions:
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The digital channel filter and demodulator are optimized for ultra low power consumption and are highly
configurable. Supported modulation types are GFSK, FSK, and OOK. The channel filter can be configured to
support bandwidths ranging from 620 kHz down to 2.6 kHz. A large variety of data rates are supported ranging
from 0.123 up to 256 kbps. The AGC algorithm is implemented digitally using an advanced control loop optimized
for fast response time.
Channel selection filter
TX modulation
RX demodulation
AGC
Preamble detector
Invalid preamble detector
Radio signal strength indicator (RSSI)
Automatic frequency compensation (AFC)
Packet handling including EZMAC
Cyclic redundancy check (CRC)
website.
for more details. When the direct tie is used, the lna_sw bit in “Register 6Dh. TX Power” must
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features
Rev 1.1
Si4430/31/32-B1
37