S i 4 x 5 5 -C
E
ASY
-
TO
- U
SE
, L
O W
- C
URRENT
OOK/(G)FSK S
UB
-GH
Z
T
RANSCEIVER
, T
RANSMITTER
,
AND
R
ECEIVER
Features
Frequency
range = 284–960 MHz
Receive sensitivity = –116 dBm
Modulation
(G)FSK
OOK
Max output power = +13 dBm
Low active power consumption
10
mA RX
18 mA TX @ +10 dBm
Low standby current = 40 nA
Low shutdown current = 30 nA
Preamble sense mode
6
Max data rate = 500 kbps
Power supply = 1.8 to 3.6 V
TX and RX 64 byte FIFOs
Automatic frequency control (AFC)
Automatic gain control (AGC)
Integrated battery voltage sensor
Packet handling including preamble,
sync word detection, and CRC
Low BOM
20-Pin 3x3 mm QFN package
mA average RX current at
1.2 kbps
Pin Assignments
GPIO3
GPIO2
XOUT
17
16 nSEL
15 SDI
14 SDO
13 SCLK
12 nIRQ
7
VDD
8
VDD
9
GND
10
GPIO0
11 GPIO1
Remote control
Home security and alarm
Telemetry
Garage and gate openers
Remote keyless entry
Home automation
Industrial control
Sensor networks
Health monitors
GND
SDN
RXp
RXn
TX
GND
1
2
3
4
5
6
20
19
18
Si4455
Description
Silicon Laboratories’ Si4455 is an easy-to-use, low current, sub-GHz
EZRadio
®
transceiver. The Si4055 is a transmit-only device, and the Si4355
is a receiver-only device based on the Si4x55 architecture. This data sheet
covers all three products with the transmit descriptions being relevant for
Si4455 and Si4055 and the receive descriptions being relevant for Si4455
and Si4355. Covering all major bands, it combines plug-and-play simplicity
with the flexibility needed to handle a wide variety of applications. The
compact 3x3 mm package size combined with a low external BOM count
makes the Si4x55 both space efficient and cost effective. The +13 dBm
output power and excellent sensitivity of –116 dBm allows for a longer
operating range, while the low current consumption of 18 mA TX (at 10 dBm),
10 mA RX, and 40 nA standby, provides for superior battery life. By fully
integrating all components from the antenna to the GPIO or SPI interface to
the MCU, the Si4x55 makes it easy to realize this performance in an
application. Design simplicity is further exemplified in the Wireless
Development Suite (WDS) user interface software. WDS provides simplified
programming options for a broad range of applications in an easy-to-use
format that results in faster and lower risk development. The Si4x55 is
capable of supporting major worldwide regulatory standards, such as FCC,
ETSI, ARIB, and China regulatory standards.
Patents pending
Rev 1.0 10/14
Copyright © 2014 by Silicon Laboratories
XIN
Applications
Si4x55-C
Si4x55-C
Functional Block Diagram
GPIO3
GPIO2
XIN XOUT
SDN
Synthesizer
25-32MHz XO
Rx Chain
SPI Interface
Controller
nSEL
SDI
SDO
SCLK
nIRQ
PGA
ADC
Rx/Tx
Modem
RXp
RXn
LNA
TX
PA
Battery
Voltage
Sensor
Aux ADC
GPIO1
VDD
GPIO0
2
Rev 1.0
Si4x55-C
T
ABLE O F
C
ONTENTS
Section
Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Typical Applications Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1. Receiver Chain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2. Receiver Modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.3. Synthesizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3.4. Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.5. Crystal Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
3.6. Battery Voltage and Auxiliary ADC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4. Configuration Options and User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1. Radio Configuration Application (RCA) GUI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.2. Configuration Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.3. Configuration Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5. Controller Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.1. Serial Peripheral Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.2. Operating Modes and Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.3. Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5.4. GPIO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6. Data Handling and Packet Handler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
6.1. RX and TX FIFOs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
6.2. Packet Handler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
6.3. Direct Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
7. Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
8. Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
9. Package Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
10. PCB Land Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
11. Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
11.1. Si4x55 Top Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
11.2. Top Marking Explanation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
Rev 1.0
3
Si4x55-C
1. Electrical Specifications
Table 1. DC Characteristics
Parameter
Supply Voltage
Range
Power Saving
Modes
Symbol
V
DD
I
Shutdown
I
Standby
I
Ready
I
SPI Active
TUNE Mode Cur-
rent
RX Mode Current
TX Mode Current
I
Tune_RX
I
Tune_TX
I
RX
I
TX
RC oscillator, main digital regulator, and low power digital
regulator OFF.
Register values maintained.
Crystal Oscillator and Main Digital Regulator ON,
all other blocks OFF.
SPI active state
RX Tune
TX Tune
Measured at 40 kbps, 20 kHz deviation, 315 MHz
+10 dBm output power
Measured on direct tie RF evaluation board at 868 MHz
+13 dBm output power
Measured on direct tie RF evaluation board at 868 MHz
—
—
—
—
—
Test Condition
Min Typ Max Unit
1.8
—
—
—
3.3
30
40
1.8
1.5
6.8
7.1
10.9
19
24
—
—
—
—
—
3.6
—
—
—
V
nA
nA
mA
mA
mA
mA
mA
mA
mA
Note:
All minimum and maximum values are guaranteed across the recommended operating conditions of supply voltage and
from –40 to +85 °C unless otherwise stated. All typical values apply at VDD = 3.3 V and 25 °C unless otherwise stated.
4
Rev 1.0
Si4x55-C
Table 2. Synthesizer AC Electrical Characteristics
Parameter
Synthesizer Frequency
Range
Symbol
F
SYN
Test Condition
Min
284
350
850
Synthesizer Frequency
Resolution
F
RES-960
F
RES-525
F
RES-420
F
RES-350
Phase Noise
Lf(fm)
850–960 MHz
420–525 MHz
350–420 MHz
283–350 MHz
DF = 10 kHz, 915 MHz
DF = 10 kHz, 915 MHz
DF = 10 kHz, 915 MHz
DF = 10 kHz, 915 MHz
—
—
—
—
—
—
—
—
Typ
—
—
—
114.4
57.2
45.6
38.1
100
102.1
123.5
136.6
Max
350
525
960
—
—
—
—
—
—
—
—
Unit
MHz
MHz
MHz
Hz
Hz
Hz
Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
Note:
All minimum and maximum values are guaranteed across the recommended operating conditions of supply voltage and
from –40 to +85 °C unless otherwise stated. All typical values apply at V
DD
= 3.3 V and 25 °C unless otherwise stated.
Rev 1.0
5