Si4020 Universal ISM
Si4020
Band FSK Transmitter
PIN ASSIGNMENT
DESCRIPTION
Silicon Labs’ Si4020 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 315, 433, 868, and 915 MHz bands.
Used in conjunction with IA4320, Silicon Labs’ FSK receiver, the Si4020
transmitter feature EZRadioTM technology, which produces 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 are needed for operation.
Microcontroller Mode
EEPROM Mode
The Si4020 features 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. In addition, highly
stable and accurate FSK modulation is accomplished by direct closed-loop
modulation with bit rates up to 256 kbps. The PLL’s high resolution allows
the use of multiple channels in any of the bands.
This document refers to Si4020-IC Rev I1.
See www.silabs.com/integration for any applicable
errata. See back page for ordering information.
FEATURES
The integrated power amplifier of the transmitter has an open-collector
differential output that 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 costly trimming procedures and de-
tuning due to the “hand effect”.
• 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
• High bit rate (up to 256 kbps)
• Direct loop antenna drive
• Automatic antenna tuning circuit
• Programmable output power level
• Alternative OOK support
For low-power applications, the device supports automatic activation from
sleep mode. Active mode can be initiated by several wake-up events (on-chip
timer timeout, low supply voltage detection, or activation of any of the four
push-button inputs).
The Si4020’s on-chip digital interface supports both a microcontroller mode
and an EEPROM mode. The latter allows complete data transmitter
operation without a microcontroller (both control commands and data are
read from the EEPROM). Any wake-up event can start a transmission of the
corresponding data stored in the EEPROM.
• EEPROM mode supported
• SPI bus for applications with microcontroller
• Clock output for microcontroller
• Integrated programmable crystal load capacitor
• Power-saving sleep mode
• Multiple event handling options for wake-up activation
• Push-button event handling with switch de-bounce
• Wake-up timer
FUNCTIONAL BLOCK DIAGRAM
• Low battery detection
• 2.2 to 5.4 V supply voltage
RFP
REFERENCE
CRYSTAL
OSCILLATOR
XTL
SYNTHESIZER
RFN
• Low power consumption
• Low standby current (0.3 µA)
CLOCK
FREQUENCY
• Compact 16-pin TSSOP package
LOAD CAP
LEVEL
OOK
MOD
TYPICAL APPLICATIONS
• Remote control
• Home security and alarm
• Wireless keyboard/mouse and other PC peripherals
• Toy control
nIRQ/nLBD
CLK/SDO
SDI
LOW BAT
LOW
BATTERY
DETECT
TRESHOLD
CONTROLLER
SCK
TIMEOUT
PERIOD
nSEL
VDD
VSS
WAKE-UP
TIMER
FSK
• Remote keyless entry
• Tire pressure monitoring
• Telemetry
• Personal/patient data logging
• Remote automatic meter reading
PB1 PB2 PB3 PB4
1
Si4020-DS Rev 1.9r 0308
www.silabs.com/integration
SILICON [ SILICON ]
