SI4322-A1-FT Silicon Laboratories Inc, SI4322-A1-FT Datasheet - Page 32

• Manufacturer Part Number: SI4322-A1-FT
• Description: IC RCVR FSK 915MHZ 3.8V 16-TSSOP
• Manufacturer: Silicon Laboratories Inc
• Type: FSK Receiverr

Specifications of SI4322-A1-FT

• Package / Case: 16-TSSOP
• Frequency: 868MHz, 915MHz
• Sensitivity: -104dBm
• Data Rate - Maximum: 256 kbps
• Modulation Or Protocol: FSK
• Applications: Remote Control, RKE, Security Systems
• Current - Receiving: 14mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Features: RSSI Equipped
• Voltage - Supply: 2.2 V ~ 3.8 V
• Operating Frequency: 915 MHz
• Operating Supply Voltage: 2.5 V, 3.3 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Supply Current: 12 mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Operating Temperature: -
• Memory Size: -
• Lead Free Status / Rohs Status: Supplier Unconfirmed
• Other names: 336-1628-5

Si4322
12. Crystal Selection Guidelines
The crystal oscillator of the Si4322 requires a 10 MHz parallel mode crystal. The circuit contains an integrated load
capacitor in order to minimize the external component count. The internal load capacitance value is programmable
from 8.5 to 16 pF in 0.5 pF steps. With appropriate PCB layout, the total load capacitance value can be 10 to 20 pF
so a variety of crystal types can be used.
When the total load capacitance is not more than 20 pF and a worst case 7 pF shunt capacitance (C
) value is
0
expected for the crystal, the oscillator is able to start up with any crystal having less than 100  ESR (equivalent
series loss resistance). However, lower C
and ESR values guarantee faster oscillator startup.
0
The crystal frequency is used as the reference of the PLL, which generates the local oscillator frequency (f
).
LO
Therefore, f
is directly proportional to the crystal frequency. The accuracy requirements for production tolerance,
LO
temperature drift and aging can thus be determined from the maximum allowable local oscillator frequency error.
Whenever a low frequency error is essential for the application, it is possible to “pull” the crystal to the accurate
frequency by changing the load capacitor value. The widest pulling range can be achieved if the nominal required
load capacitance of the crystal is in the “midrange”, for example 16 pF. The “pull-ability” of the crystal is defined by
its motional capacitance and C
.
0
The on chip AFC is capable to correct TX/RX carrier offsets as much as 80% of the deviation of the received FSK
modulated signal.
32
Rev. 1.2