SI4022 Datasheet, PDF (1/22 Pages) Silicon Laboratories – Programmable output power level

Si4022 Universal ISM Band
FSK Transmitter
DESCRIPTION
Silicon Labs’ Si4022 is a single chip, low power, multi-channel FSK
transmitter designed for use in applications requiring FCC or ETSI
conformance for unlicensed use in the bands at 868 and 915 MHz. Used in
conjunction with Integration’s FSK receivers, it is a flexible, low cost, and
highly integrated solution that does not require production alignments. All
required RF functions are integrated. Only an external crystal and bypass
filtering is needed for operation.
The transmitter has a completely integrated PLL for easy RF design, and its
rapid settling time allows for fast frequency-hopping, bypassing multipath
fading and interference to achieve robust wireless links. The PLL’s high
resolution allows the usage of multiple channels in any of the bands. In
addition, highly stable and accurate FSK modulation is accomplished by
direct closed-loop modulation with bit rates up to 115.2 kbps.
The integrated power amplifier of the transmitter has an open-collector
differential output and can directly drive a loop antenna with programmable
output level, no additional matching network is required. An automatic
antenna tuning circuit is built in to avoid both costly trimming procedures
and de-tuning due to the “hand effect”.
For battery-operated applications the device supports various power saving
modes with wake-up interrupt generation options based on a low battery
voltage detector and a sleep timer. Several additional features ease system
design. Power-on reset and clock signals are provided to the microcontroller.
An on-chip baud rate generator and a data FIFO are available. The transmitter
is programmed and controlled via an SPI compatible interface.
FUNCTIONAL BLOCK DIAGRAM
XTL 9
VDD 15
VSS_A 11
VDD_B 14
VSS_D 8
VREFO 7
CRYSTAL
OSCILLATOR
LOW
BATTERY
DETECT
WAKE -UP
TIMER
REFERENCE
SYNTHESIZER
LOAD CAP
CLOCK
FREQUENCY
LEVEL
LOW BAT
TRESHOLD
TIMEOUT
PERIOD
CONTROLLER
10
nRES
222-DS rev 1.1r 030
13 RF02
12 RF01
6 CLK
5 nIRQ
4 SDO
1 SDI
2 SCK
3 nSEL
16 FSK
Si4022
PIN ASSIGNMENT
SDI 1
SCK 2
nSEL 3
SDO 4
nIRQ 5
CLK 6
VREFO 7
VSS_D 8
16 FSK
15 VDD
14 VSS_B
13 RF02
12 RF01
11 VSS_A
10 nRES
9 XTL / REF
This document refers to Si4022-IC Rev A0.
See www.silabs.com/integration for any applicable
errata. See back page for ordering information.
FEATURES
• Fully integrated (low BOM, easy design-in)
• No alignment required in production
• Fast settling, programmable, high-resolution PLL
• Fast frequency hopping capability
• Stable and accurate FSK modulation with
programmable deviation
• Programmable PLL loop bandwidth
• Direct loop antenna drive
• Automatic antenna tuning circuit
• Programmable output power level
• SPI bus for interfacing with microcontroller
• Clock and reset signals for microcontroller
• 64 bit TX data FIFO
• Integrated programmable crystal load capacitor
• Standard 10 MHz crystal reference
• Power-saving modes
• Multiple event handling options for wake-up
activation
• Wake-up timer
• Low battery detection
• 2.2 to 3.8 V supply voltage
• Low power consumption
• Low standby current (typ. 0.3 μA)
TYPICAL APPLICATIONS
• Remote control
• Home security and alarm
• Wireless keyboard/mouse and other PC peripherals
• Toy control
• Remote keyless entry
• Tire pressure monitoring
• Telemetry
• Personal/patient data logging
• Remote automatic meter reading
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