SILABS SI4312

Si4312
315/433.92 MH Z O O K R ECEIVER
Features



Applications




Satellite set-top box receivers
Remote controls, IR
replacement/extension
 Garage and gate door openers
 Home automation and security
Ordering Information:
See page 15.
Remote keyless entry
After market alarms
 Telemetry
 Wireless point of sale
 Toys
Pin Assignments
Si4312
(Top View)
Description
1
20
19
18
17
16
RFGND 2
15 BT0
RX_IN 3
14 BT1
GND
PAD
RST 4
13 DOUT
6
7
8
9
10
XTL1
XTL2
12 GND
VDD
RATIO 5
GND
Functional Block Diagram
VDD
315/434
The Si4312 is a fully-integrated OOK CMOS RF receiver that operates in the
unlicensed 315 and 433.92 MHz ultra high frequency (UHF) bands. It is designed
for high-volume, cost-sensitive RF receiver applications, such as set-top box RF
receivers, remote controls, garage door openers, home automation, security,
remote keyless entry systems, wireless POS, and telemetry. The Si4312 offers
industry-leading RF performance, high integration, flexibility, low BOM, small
board area, and ease of design. No production alignment is necessary as all RF
functions are integrated into the device.
TH1


TH0


Data rates up to 10 kbps NRZ
(5 kbps Manchester)
Direct battery operation with onchip low drop out (LDO) voltage
regulator
16 MHz crystal oscillator support
3x3x0.85 mm 20L QFN package
(RoHS compliant)
–40 to +85 °C temperature range
NC


NC

Single chip receiver with only six
external components
Selectable 315/433.92 MHz carrier
frequency
Supports OOK modulation
High sensitivity
(–110 dBm @ 1.0 kbps)
Frequency scanning
Excellent interference rejection
NC

11 VDD
Patents pending
Si4312
Antenna
LNA
PGA
ADC
AGC
2.7 – 3.6 V
VDD
GND
DOUT
ADC
RX_IN
LDO
FREQ
SCAN
XTAL
OSC
DSP
MCU
BASEBAND
PROCESSOR
SQUELCH
RATIO
315/434
TH[1:0]
BT[1:0]
RST
16 MHz
Rev. 0.5 3/10
Copyright © 2010 by Silicon Laboratories
Si4312
This information applies to a product under development. Its characteristics and specifications are subject to change without notice.
Si4312
2
Rev. 0.5
Si4312
TABLE O F C ONTENTS
Section
Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Typical Application Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
2.1. Typical Application Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
3.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
3.2. Receiver Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
3.3. Carrier Frequency Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
3.4. Bit Time BT[1:0] Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
3.5. RATIO Selection Used for the Slicer Threshold Calculation Window . . . . . . . . . . . . 10
3.6. Frequency Scanning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
3.7. Threshold Hold Time Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.8. Low Noise Amplifier Input Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.9. Crystal Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
3.10. Reset Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4. Pin Descriptions: Si4312-B10-GM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6. Package Markings (Top Marks) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.1. Si4312 Top Mark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6.2. Top Mark Explanation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
7. Package Outline: Si4312-B10-GM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8. PCB Land Pattern: Si4312-B10-GM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Rev. 0.5
3
Si4312
1. Electrical Specifications
Table 1. Recommended Operating Conditions*
Parameter
Symbol
Min
Typ
Max
Unit
VDD
2.7
3.3
3.6
V
VDD-RISE
10
—
—
μs
TA
–40
25
85
°C
Supply Voltage
Supply Voltage Powerup Rise Time
Ambient Temperature
Test Condition
*Note: All minimum and maximum specifications are guaranteed and apply across the recommended operating conditions.
Typical values apply at VDD = 3.3 V and 25 C unless otherwise stated. Parameters are tested in production unless
otherwise stated.
Table 2. Absolute Maximum Ratings1,2
Parameter
Symbol
Value
Unit
VDD
–0.5 to 3.9
V
3
Input Current
IIN
10
mA
Input Voltage3
VIN
–0.3 to (VDD + 0.3)
V
Operating Temperature
TOP
–45 to 95
C
Storage Temperature
TSTG
–55 to 150
C
0.4
VPK
Supply Voltage
4
RF Input Level
Notes:
1. Permanent device damage may occur if the absolute maximum ratings are exceeded. Functional operation should be
restricted to the conditions as specified in the operational sections of this data sheet. Exposure beyond recommended
operating conditions for extended periods may affect device reliability.
2. The Si4312 device is a high-performance RF integrated circuit with certain pins having an ESD rating of < 2 kV HBM.
Handling and assembly of this device should only be done at ESD-protected workstations.
3. For input pins 315/434, RATIO, BT[1:0], TH[1:0].
4. At RF input pin RX_IN.
4
Rev. 0.5
Si4312
Table 3. DC Characteristics
(TA = 25 °C, VDD = 3.3 V, Rs = 50 Ω, FRF = 433.92 MHz unless otherwise noted)
Parameter
Symbol
Test Condition
IVDD
Supply Current
IRST
Reset Supply Current
Reset asserted
Min
Typ
Max
Unit
—
20
TBD
mA
—
2
TBD
µA
1
VIH
0.7 x VDD
—
VDD + 0.3
V
Low Level Input Voltage1
VIL
–0.3
—
0.3 x VDD
V
1
IIH
VIN = VDD = 3.6 V
–10
—
10
µA
Low Level Input Current1
High Level Input Voltage
High Level Input Current
IIL
VIN = 0 V, VDD = 3.6 V
–10
—
10
µA
Voltage2
VOH
IOUT = 500 µA
0.8 x VDD
—
—
V
Low Level Output Voltage2
VOL
IOUT = –500 µA
—
—
0.2 x VDD
V
High Level Output
Notes:
1. For input pins OOK, 315/434, RATIO, BT[1:0], TH[1:0].
2. For output pin DOUT.
Table 4. Reset Timing Characteristics
(VDD = 3.3 V, TA = 25 °C)
Parameter
Symbol
Min
Typ
Max
Unit
tSRST
100
—
—
µs
RST Pulse Width
tSRST
RST
70%
30%
Figure 1. Reset Timing
Rev. 0.5
5
Si4312
Table 5. Si4312 Receiver Characteristics
(TA = 25 °C, VDD = 3.3 V, Rs = 50 Ω, FRF = 433.92 MHz unless otherwise noted)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
1.0 kbps, 315 MHz
(Note2)
—
–110
—
dBm
10 kbps, 315 MHz
(Note2)
—
–103
—
dBm
—
–106
—
dBm
10 kbps, 433.92 MHz
TBD
–101
—
dBm
NRZ
—
—
10
kbps
Adjacent Channel Rejection
±200 kHz (Note 1)
Desired signal is 3 dB above sensitivity
(BER = 10–3), unmodulated interferer
is at ±200 kHz, rejection measured as TBD
difference between desired signal and
interferer level in dB when BER = 10–3
35
—
dB
Alternate Channel Rejection
±400 kHz1,2
Desired signal is 3 dB above sensitivity
(BER = 10–3), unmodulated interferer
is at ±400 kHz, rejection measured as
difference between desired signal and
interferer level in dB when BER = 10–3
—
55
—
dB
—
23
—
dB
±2 MHz, 1.0 kbps, desired signal is
3 dB above sensitivity, CW interferer
level is increased until BER = 10–3
—
65
—
dB
±10 MHz, 1.0 kbps, desired signal is
3 dB above sensitivity, CW interferer
level is increased until BER = 10–3
—
70
—
dB
—
8
—
dBm
—
–10
—
dBm
—
7
—
pF
—
160
—
kHz
—
500
—
ms
Sensitivity @ BER = 10–3 (Note 1)
1.0 kbps, 433.92 MHz
3
Data Rate
(Note2)
Image Rejection, IF = 128 kHz1,2
Blocking1,2
Maximum RF Input Power 1,2
| f2 – f1 | = 5 MHz, high gain mode,
desired signal is 3 dB above sensitivity,
CW interference levels are increased
until BER = 10–3
Input IP33
LNA Input Capacitance3
Receiver Channel Bandwidth
4
RX Boot Time3
From reset
Notes:
1. 1.0 kbps, Manchester encoded, RATIO = 0, TH[1:0] = 00, xtal = ±20 ppm.
2. Guaranteed by characterization.
3. Guaranteed by design.
4. The frequency scanning (see section “3.6. Frequency Scanning”) extends this to 420 kHz.
Table 6. Crystal Characteristics
(VDD = 3.3 V, TA = 25 °C)
Min
Typ
Crystal Oscillator Frequency
—
Crystal ESR
—
XTL1, XTL2 Input Capacitance
—
Parameter
6
Symbol
Test Condition
Rev. 0.5
Max
Unit
16
—
MHz
—
100

11
—
pF
Si4312
2. Typical Application Schematic
20
19
18
17
16
NC
NC
NC
TH0
TH1
VDD
1
VDD
2
RFGND
3
U1
RX_IN
Si4312-GM
4
RST
5
RATIO
L1
C3
VDD 11
DOUT
VDD
C1
22 nF
VBATTERY
2.7 to 3.6 V
6
7
8
9
10
GND
PAD
C2
1 uF
BT0 15
BT1 14
DOUT 13
GND 12
434
GND
VDD
XTL1
XTL2
RX
ANTENNA
R1
20 k
TH0
TH1
BT0
BT1
RATIO
X1 (16 MHz)
Figure 2. Si4312 OOK 433.92 MHz Application Schematic
2.1. Typical Application Bill of Materials
Table 7. Si4312 Typical Application Bill of Materials
Component(s)
Value/Description
Supplier(s)
C1
Supply bypass capacitor, 22 nF, 20%, Z5U/X7R
Murata
C2
Time constant capacitor, 1 µF
Murata
C3
Antenna matching capacitor, 15 pF
Murata
L1
Antenna matching inductor,
33 nH for 433.92 MHz and 62 nH for 315 MHz
Murata
R1
Time constant resistor, 20 k
Murata
X1
16 MHz crystal
Hosonic
U1
Si4312 315/433.92 MHz OOK receiver
Silicon Laboratories
Rev. 0.5
7
Si4312
3. Functional Description
3.1. Overview
Si4312
Antenna
LNA
PGA
ADC
AGC
2.7 – 3.6 V
VDD
GND
DOUT
ADC
RX_IN
LDO
FREQ
SCAN
DSP
MCU
BASEBAND
PROCESSOR
SQUELCH
XTAL
OSC
RATIO
315/434
TH[1:0]
BT[1:0]
RST
16 MHz
Figure 3. Functional Block Diagram
The Si4312 is a fully-integrated OOK CMOS RF
receiver that operates in the unlicensed 315 and 433.92
MHz ultra high frequency (UHF) bands. It is designed
for high-volume, cost-sensitive RF receiver applications.
The chip operates at a carrier frequency of 315 or
433.92 MHz and supports OOK digital modulation with
data rates of up to 10 kbps NRZ or 5 kbps Manchester
coded. The Si4312 has selectable data filters to
optimize the sensitivity of the receiver for a given data
rate. The Si4312 employs a frequency scanning
algorithm to improve the sensitivity of the receiver with a
small IF bandwidth while still maintaining the ability to
accommodate large transmit frequency offsets. The
integrated on-chip squelch circuit prevents false output
data when the RF input signal is absent or below
sensitivity.
The device leverages Silicon Labs’ patented and proven
digital low-IF architecture and offers superior sensitivity
and interference rejection. The Si4312 can achieve
superior sensitivity in the presence of large interference
due to its high dynamic range ADCs and digital filters.
The digital low-IF architecture also enables superior
blocking ability and low intermodulation distortion for
robust reception in the presence of wide-band
interference.
area. The high integration of the Si4312 improves the
system manufacturing reliability, improves quality, eases
design-in, and minimizes costs.
3.2. Receiver Description
The RF input signal is amplified by a low-noise amplifier
(LNA) and down-converts to a low intermediate
frequency with a quadrature image-reject mixer. The
mixer output is amplified by a programmable gain
amplifier (PGA), filtered, and digitized with a highresolution analog-to-digital converter (ADC). All RF
functions are integrated into the device eliminating any
production alignment issues associated with external
components, such as SAW and ceramic IF filters.
Silicon Labs’ advanced digital low-IF architecture
achieves superior performance by using the DSP to
perform channel filtering, demodulation, automatic gain
control (AGC), automatic frequency control (AFC), and
other baseband processing. DSP implementation of the
channel filters provides better repeatability and control
of the bandwidth and frequency response of the filter
compared to analog implementations. No off-chip
ceramic filters are needed with the Si4312 as all IF
channel filtering is performed in the digital domain.
Digital integration reduces the number of required
external components compared to traditional offerings,
resulting in a solution that only requires a 16 MHz
crystal and passive components allowing a small and
compact printed circuit board (PCB) implementation
8
Rev. 0.5
Si4312
3.3. Carrier Frequency Selection
The Si4312 can be tuned to either 315 or 433.92 MHz by driving Pin 6 (315/434) to VDD or GND. The 315 MHz
operation is chosen by driving Pin 6 (315/434) to VDD, and 433.92 MHz operation is chosen by driving Pin 6
(315/434) to GND.
Table 8. Carrier Frequency Selection
Pin 6 (315/434)
Frequency [MHz]
0
433.92
1
315
3.4. Bit Time BT[1:0] Selection
The Si4312 can operate with data rates of up to 10 kbps non-return to zero (NRZ) data or 5 kbps Manchester
encoded data. However, OOK modulation uses other encoding schemes such as pulse width modulation (PWM)
and pulse position modulation (PPM) where a bit can be encoded into a pulse with a certain duty cycle or pulse
width as shown in Figure 4.
Digital Data
“1”
“0”
“1”
“1”
NRZ
Encoding
Manchester
Encoding
PPM
Encoding
100 us
1000 us
Figure 4. Example Data Waveforms
In order to set the data filter bandwidth correctly, the shortest pulse width of the transmitted encoded data should
be chosen as the bit time. In the PPM example shown in Figure 4, the shortest pulse width is 100 µs; so, the bit
time is chosen as BT = 100 µs even though the actual data rate is 1 kbps (1000 µs). After finding BT, Table 9 can
be used to find the bit settings for pins 14 and 15, BT[1:0]. In this PPM example, BT[1:0] is set as logic BT1 = 1 and
BT0 = 1 or BT[1:0] = (1,1) since BT = 100 µs.
Table 9. How to Choose BT[1:0] Based on the Bit Time
Bit Time [µs]
Filter Bandwidth [kHz]
BT1 (pin 14)
BT0 (pin 15)
BT ≥ 1000
1.5
0
0
1000 < BT < 500
3.0
0
1
500 < BT < 200
7.5
1
0
200 < BT < 100
15
1
1
Rev. 0.5
9
Si4312
3.5. RATIO Selection Used for the Slicer Threshold Calculation Window
In OOK modulation, many different encoding schemes exist, which can result in variable ON and OFF times as
seen in the example data waveforms shown in Figure 4. In order to determine the proper slicer threshold used for
demodulating the OOK signal into digital data, the Si4312 must sample an "ON" and "OFF" event in a time window
called the threshold calculation window. The samples during the "ON" time will determine the ON voltage, and the
samples during the "OFF" time will determine the OFF voltage. These voltages are used to determine the slicer
threshold voltage as follows:
Max_ON_Voltage + Min_OFF_Voltage SlicerThreshold = ---------------------------------------------------------------------------------------------------------2
Defining the BT variable from the last section as the ON time and
RATIO = OFF
-----------ON
then, the threshold calculation window is calculated as follows:
Threshold Calculation Window = 1.25   ON + OFF 
= 1.25   BT + BT  RATIO 
= 1.25  BT  RATIO + 1 
The threshold calculation window is 1.25 times longer than the ON plus OFF times for margin to allow sampling of
both ON and OFF times. Figure 5 shows a graph of the threshold calculation window.
Digital Data
PPM
Encoding
“1”
“0”
“1”
“1”
100 us
1000 us
ON voltage
OOK
Waveform
OFF voltage
Threshold Calculation Window
Figure 5. Example of the Threshold Calculation
Ratio is a unit-less multiplier that relates the OFF time to the ON time. The Si4312 defines two constants for RATIO
as shown in Table 10 based on the logic level of pin 5.
Table 10. RATIO Constants Based on Logic Level of Pin 5
10
Pin 5
RATIO
0
5
1
10
Rev. 0.5
Si4312
Since the OFF time = RATIO x BT and the values for RATIO are either 5 or 10, RATIO should be chosen such that
either the value of 5 or 10 x the BT[1:0] setting is just larger than the OFF time. For the PPM example shown in
Figure 4, BT[1:0] = (1,1) since BT = 100 µs. The actual OFF time is 900 µs; so, we would set pin 5 = 1 to get a
RATIO of 10 such that the calculated OFF time is BT[1:0] x RATIO = 100 µs x 10 = 1000 µs, which is greater than
the actual OFF time of 900 µs.
An alternative approach to choosing the RATIO bit (pin 5) is to choose the RATIO parameter such that the
threshold calculation window is greater than the actual ON plus OFF times using Table 11 and the values chosen
for BT[1:0].
Table 11. Threshold Calculation Window Times Based on RATIO and BT[1:0] Settings
RATIO
BT1
BT0
Threshold Calculation Window (ms)
0
0
0
7.500
0
0
1
3.750
0
1
0
1.500
0
1
1
0.750
1
0
0
13.750
1
0
1
6.875
1
1
0
2.750
1
1
1
1.375
3.6. Frequency Scanning
The channel bandwidth directly affects the sensitivity of any wireless receiver. Typical analog OOK receivers use
an external ceramic filter with a large bandwidth to accommodate the data rate, crystal tolerances, and transmit
carrier frequency offsets, which leads to unnecessary amounts of noise and lower sensitivity levels. The Si4312
uses a narrow channel bandwidth of 160 kHz and frequency scanning to obtain excellent sensitivity levels
(–110 dBm at data rate of 1 kbps at 315 MHz) while still accommodating up to ±210 kHz of scan bandwidth from its
operating frequency.
The frequency scan algorithm works by breaking the scan bandwidth (420 kHz) into three frequency bins
approximately 140 kHz wide and checking for transmit signal energy in each bin. Because the received signal
power can vary by large orders of magnitude depending on how close the transmitter is to the receiver, the
frequency algorithm may have to re-scan the frequency bins if the received power level saturates the receiver.
Three gain settings are used in the frequency scan algorithm denoted as high-, medium-, and low-gain.
The chip begins scanning the frequency in the highest receiver gain setting to find signals that have a receive
signal strength indicator (RSSI) level from sensitivity to about –70 dBm. If energy is detected in only one of these
frequency bands, it is double-checked again and deemed as the correct operating frequency band. Therefore, the
frequency scan algorithm takes at least two searches to find the correct frequency band. The scan time per
frequency bin search is equal to the threshold calculation window time as chosen by the RATIO and BT[1:0]
settings given in Table 11. Therefore, the best case frequency scan time is equal to two times the threshold
calculation window time.
In case the input signal is large while the gain is also large, the receiver could be overloaded; therefore, the
frequency scan algorithm follows a series of frequency and gain level settings based on measured RSSI as shown
in Figure 6. In the worst case, there are a total of nine frequency bin searches (three frequency bins times three
gain settings) plus one additional frequency re-scan because we don't know when the signal starts or for double
checking. Thus, the worst-case scan time is equal to 10 times the threshold calculation window time. Figure 6
shows the frequency scan algorithm broken into three frequency bins of 140 kHz and three gain settings.
Rev. 0.5
11
Si4312
Low Gain:
Input RSSI in the range of
-45dBm ~ -15dBm
Scan
Directions
Medium Gain:
Input RSSI in the range of
-75dBm to -40dBm
High Gain:
Input RSSI in the range of
Sensitivity to -70dBm
Fc
Freq Bin 2
Freq Bin 1
Freq Bin 3
Figure 6. Frequency Scan Algorithm Depicting 3 Frequency Bins of 140 kHz and 3 Gain Settings
Frequency scanning is always enabled to find the transmitted signal. The scanning process stops after the correct
frequency band is found for the transmitted signal and is held throughout the duration of the packet plus a time of
no RF signal activity. This dead time is called “threshold hold time” and is described in section 3.7. Theshold hold
time allows a frequency found in the first packet of transmission to be held for any subsequent retransmissions of
packets if the retransmissions occur before the threshold hold time. This held frequency ensures all bits of the
second and subsequent packets are recovered completely. Frequency scanning resumes after the time of no RF
signal activity exceeds the threshold hold time.
3.7. Threshold Hold Time Selection
The threshold hold time is defined as the length of time the Si4312 keeps its slicer threshold voltage level when no
signals are present. If a signal does not appear after this time interval, the Si4312 will re-start the frequency scan
process and look for the signal in one of its three frequency bins. The threshold hold times are determined by the
bit settings chosen on pins 16 and 17 as shown in Table 12.
Table 12. Threshold Time Settings Based on TH[1:0] Logic Levels
TH1 (Pin 16)
TH0 (Pin 17)
Threshold Hold Time (ms)
0
0
70
0
1
100
1
0
300
1
1
500
3.8. Low Noise Amplifier Input Circuit
Figure 2 shows the typical application circuit with 50  matching. Components C3 and L1 are used to transform the
input impedance of the LNA. C3 is equal to 15 pF and L1 is equal to 33 nH at 433.92 MHz and 62 nH at 315 MHz
for 50  matching.
12
Rev. 0.5
Si4312
3.9. Crystal Oscillator
An on-board crystal oscillator is used to generate a 16 MHz reference clock for the Si4312. This reference
frequency is required for proper operation of the Si4312 and is used for calibration of the on-chip VCO and other
timing references. No external load capacitors are required to set the 16 MHz reference frequency if the
recommended crystal load capacitor is around 14 pF, assuming the effective board capacitance between pins
XTL1 and XTL2 is 3 pF and the chip input capacitance on pins XTL1 or XTL2 is 11 pF. Refer to Table 6, “Crystal
Characteristics,” on page 6 for board capacitance and frequency tolerance information. The frequency tolerance of
the crystal should be chosen such that the received signal is within the IF bandwidth of the Si4312 receiver.
Additionally, the Si4312 can be driven by an external 16 MHz reference clock. The clock signal can be applied to
either the XTL1 or XTL2 inputs. When the 16 MHz reference clock is applied to one of the inputs, the other crystal
input pin must be floating.
3.10. Reset Pin
Driving the RST pin (pin 4) low will disable the Si4312 and place the device into reset mode. All active blocks in the
device are powered off in this mode, bringing the current consumption to less than 10 uA. The Si4312 is enabled
by driving the RST pin (pin 4) to VDD. Refer to Table 4 "Reset Timing Characteristics" for the reset timing
requirements. The chip requires about 500 ms to go from reset to active mode. The Si4312 can output invalid data
during the 500 ms turn-on time.
Rev. 0.5
13
Si4312
NC
TH0
TH1
1
NC
VDD
NC
4. Pin Descriptions: Si4312-B10-GM
20
19
18
17
16
RFGND 2
15 BT0
RX_IN 3
14 BT1
GND
PAD
RST 4
13 DOUT
14
6
7
8
9
10
GND
VDD
XTL1
XTL2
12 GND
315/434
RATIO 5
11 VDD
Pin Number(s)
Name
Description
1, 8, 11
VDD
2
RFGND
3
RX_IN
4
RST
5
RATIO
6
315/434
7, 12, GND PAD
GND
Ground. Connect to ground plane on PCB.
9
XTL1
Crystal input.
10
XTL2
Crystal input.
13
DOUT
Data output.
14, 15
BT[1:0]
Bit time selection input pins.
16, 17
TH[1:0]
Threshold hold time selection input pins.
18,19,20
NC
Supply voltage, may connect to external battery.
RF ground. Connect to ground plane on PCB.
RF receiver input.
Device reset, active low input.
Constant used to determine threshold calculation window, input
pin.
Selectable logic input for 315 or 433.92 MHz operation.
No connect. Leave floating.
Rev. 0.5
Si4312
5. Ordering Guide
Part Number*
Si4312-B10-GM
Description
315/433.92 MHz OOK Receiver
Package
Type
Operating
Temperature
QFN
Pb-free
–40 to 85 °C
*Note: Add an “(R)” at the end of the device part number to denote tape and reel option.
Rev. 0.5
15
Si4312
6. Package Markings (Top Marks)
6.1. Si4312 Top Mark
1210
RTTT
YWW
Figure 7. Si4312 Top Mark Example
6.2. Top Mark Explanation
Mark Method:
YAG Laser
Line 1 Marking:
Part Number
12 = Si4312
Firmware Revision
10 = Firmware Revision 1.0
Die Revision
B = Revision B Die
TTT = Internal Code
Internal tracking code
Line 2 Marking:
Line 3 Marking:
Circle = 0.5 mm Diameter Pin 1 Identifier
(Bottom-Left Justified)
YWW = Date Code
16
Assigned by the Assembly House. Corresponds to the last digit
of the current year (Y) and the workweek (WW) of the mold
date.
Rev. 0.5
Si4312
7. Package Outline: Si4312-B10-GM
Figure 8 illustrates the package details for the Si4312-B10-GM. Table 13 lists the values for the dimensions shown
in the illustration.
Figure 8. 20-Pin Quad Flat No-Lead (QFN)
Table 13. Package Dimensions
Symbol
Millimeters
Symbol
Millimeters
Min
Nom
Max
A
0.80
0.85
0.90
f
A1
0.00
0.02
0.05
L
0.30
0.35
0.40
b
0.20
0.25
0.30
L1
0.00
—
0.10
c
0.27
0.32
0.37
aaa
—
—
0.05
bbb
—
—
0.05
ccc
—
—
0.08
D
D2
Min
3.00 BSC
1.65
1.70
1.75
Nom
Max
2.53 BSC
e
0.50 BSC
ddd
—
—
0.10
E
3.00 BSC
eee
—
—
0.10
E2
1.65
1.70
1.75
Notes:
1. All dimensions are shown in millimeters (mm) unless otherwise noted.
2. Dimensioning and tolerancing per ANSI Y14.5M-1994.
Rev. 0.5
17
Si4312
8. PCB Land Pattern: Si4312-B10-GM
Figure 9 illustrates the PCB land pattern details for the Si4312-B10-GM. Table 14 lists the values for the
dimensions shown in the illustration.
Figure 9. PCB Land Pattern
18
Rev. 0.5
Si4312
Table 14. PCB Land Pattern Dimensions
Symbol
Millimeters
Min
D
D2
Symbol
Max
2.71 REF
1.60
1.80
Min
Max
GE
2.10
—
W
—
0.34
—
e
0.50 BSC
X
E
2.71 REF
Y
E2
f
GD
1.60
1.80
2.53 BSC
2.10
Millimeters
0.28
0.61 REF
ZE
—
3.31
ZD
—
3.31
—
Notes:
General
1. All dimensions shown are in millimeters (mm) unless otherwise noted.
2. Dimensioning and tolerancing is per the ANSI Y14.5M-1994 specification.
3. This land pattern design is based on IPC-SM-782 guidelines.
4. All dimensions shown are at Maximum Material Condition (MMC). Least Material
Condition (LMC) is calculated based on a fabrication allowance of 0.05 mm.
Solder Mask Design
5. All metal pads are to be non-solder-mask-defined (NSMD). Clearance between the
solder mask and the metal pad is to be 60 µm minimum, all the way around the pad.
Stencil Design
6. A stainless steel, laser-cut and electro-polished stencil with trapezoidal walls should
be used to assure good solder paste release.
7. The stencil thickness should be 0.125 mm (5 mils).
8. The ratio of stencil aperture to land pad size should be 1:1 for the perimeter pads.
9. A 1.45 x 1.45 mm square aperture should be used for the center pad. This provides
approximately 70% solder paste coverage on the pad, which is optimum to assure
correct component standoff.
Card Assembly
10. A No-Clean, Type-3 solder paste is recommended.
11. The recommended card reflow profile is per the JEDEC/IPC J-STD-020 specification
for small body components.
Rev. 0.5
19
Si4312
NOTES:
20
Rev. 0.5
Si4312
DOCUMENT CHANGE LIST
Revision 0.1 to 0.2

Updated sensitivity and supply current.
Revision 0.2 to 0.5

Removed IVDD current spec when input = –30 dBm
from Table 3 "DC Characteristics"
 Updated sensitivity specs and test conditions in
Table 5 "Si4312 Receiver Characteristics"
 Updated frequency scanning description in section
“3.6. Frequency Scanning”
 Added reference clock drive capability to section
“3.9. Crystal Oscillator”
Rev. 0.5
21
Si4312
CONTACT INFORMATION
Silicon Laboratories Inc.
400 West Cesar Chavez
Austin, TX 78701
Tel: 1+(512) 416-8500
Fax: 1+(512) 416-9669
Toll Free: 1+(877) 444-3032
Email: [email protected]
Internet: www.silabs.com
The information in this document is believed to be accurate in all respects at the time of publication but is subject to change without notice.
Silicon Laboratories assumes no responsibility for errors and omissions, and disclaims responsibility for any consequences resulting from
the use of information included herein. Additionally, Silicon Laboratories assumes no responsibility for the functioning of undescribed features
or parameters. Silicon Laboratories reserves the right to make changes without further notice. Silicon Laboratories makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Silicon Laboratories assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. Silicon Laboratories products are not designed, intended, or authorized for use in applications intended to
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Other products or brandnames mentioned herein are trademarks or registered trademarks of their respective holders.
22
Rev. 0.5