AX5051 D

AX5051
Advanced Multi-channel
Single Chip UHF Transceiver
OVERVIEW
The AX5051 is a true single chip low−power CMOS transceiver
primarily for use in SRD bands. The on−chip transceiver consists of a
fully integrated RF front−end with modulator, and demodulator. Base
band data processing is implemented in an advanced and flexible
communication controller that enables user−friendly communication
via the SPI interface.
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Features
• Advanced Multi−channel Single Chip UHF Transceiver
• Configurable for Usage in 400−470 MHz and 800−940 MHz
SRD Bands
• Wide Variety of Shaped Modulations Supported in RX and TX
(ASK, PSK, MSK, FSK)
• Data Rates from 1 to 350 kbps (FSK, MSK), 1 to 600 kbps (ASK),
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28
QFN28 5x5, 0.5P
CASE 485EF
ORDERING INFORMATION
Device
Type
Qty
AX5051−1−TA05
Tape & Reel
500
10 to 600 kbps (PSK)
AX5051−1−TW30
Tape & Reel
3,000
Ultra Fast Settling RF Frequency Synthesizer for Low−power
Consumption
Variable Channel Filtering from 40 kHz to 600 kHz
RF Carrier Frequency and FSK Deviation
• Programmable Cyclic Redundancy Check
Programmable in 1 Hz Steps
(CRC−CCITT, CRC−16, CRC−32)
Fully Integrated Frequency Synthesizer with VCO
• Optional Spectral Shaping Using a Self Synchronizing
Auto−ranging and Band−width Boost Modes for Fast
Shift Register
Locking
• Brown−out Detection
Few External Components
• Integrated RX/TX Switching
On−chip Communication Controller and Flexible
• Differential Antenna Pins
Digital Modem
• RoHS Compliant
Channel Hopping up to 2000 hops/s
Applications
Sensitivity down to −116 dBm at 1.2 kbps
• Telemetry
Up to +16 dBm Programmable Transmitter Power
• Sensor Readout, Thermostats
Amplifier
• AMR
Crystal Oscillator with Programmable
• Toys
Transconductance and Programmable Internal Tuning
Capacitors for Low Cost Crystals
• Wireless Audio
Automatic Frequency Control (AFC)
• Wireless Networks
SPI Micro−controller Interface
• Wireless M−Bus
Fully Integrated Current/Voltage References
• Access Control
QFN28 Package
• Remote Keyless Entry
Low Power Receiver: 18 − 21 mA in High Sensitivity
• Remote Controls
Mode and 16 − 18 mA in Low Power Mode
• Active RFID
Low Power Transmitter: 11 − 45 mA during Transmit
• Compatible with FCC Part 15.247, FCC Part 15.249,
Extended Supply Voltage Range 2.2 V − 3.6 V
EN 300 220 Wide Band, Wireless M−Bus S/T Mode
Internal Power−on−reset
868 MHz, Konnex RF, ARIB T−67, 802.15.4
32 Bit RX/TX Data FIFO
© Semiconductor Components Industries, LLC, 2016
April, 2016 − Rev. 3
1
Publication Order Number:
AX5051/D
AX5051
BLOCK DIAGRAM
Digital IF
channel
filter
ADC
ANTP 4
RSSI
ANTN 5
AGC
Modulator
PA
Crystal
Oscillator
typ.
16 MHz
De−
modulator
FIFO
IF Filter &
AGC PGAs
Framing
LNA
AX5051
Encoder
Mixer
FOUT
FXTAL RF Frequency
Generation
Subsystem
Chip configuration
Communication Controller &
Serial Interface
Divider
16 17
Figure 1. Functional Block Diagram of the AX5051
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12
RESET_N
19
IRQ
MOSI
MISO
SEL
VDD_IO
VREG
CLK
14 15
13
SYSCLK
CLK16N
CLK16P
27 28
AX5051
Table 1. PIN FUNCTION DESCRIPTIONS
Pin(s)
Type
NC
Symbol
1
N
Not to be connected
Description
VDD
2
P
Power supply, must be supplied with regulated voltage VREG
GND
3
P
Ground
ANTP
4
A
Antenna input/output
ANTN
5
A
Antenna input/output
GND
6
P
Ground
VDD
7
P
Power supply, must be supplied with regulated voltage VREG
NC
8
N
Not to be connected
TST1
9
I
Must be connected to GND
TST2
10
I
Must be connected to GND
GND
11
P
Ground
RESET_N
12
I
Optional reset input
If this pin is not used it must be connected to VDD_IO
SYSCLK
13
I/O
SEL
14
I
Serial peripheral interface select
CLK
15
I
Serial peripheral interface clock
MISO
16
O
Serial peripheral interface data output
MOSI
17
I
Serial peripheral interface data input
TST3
18
I
Must be connected to GND
IRQ
19
I/O
VDD_IO
20
P
Unregulated power supply
NC
21
N
Not to be connected
GND
22
P
Ground
NC
23
N
Not to be connected
VREG
24
P
Regulated output voltage
VDD pins must be connected to this supply voltage
A 1 mF low ESR capacitor to GND must be connected to this pin
NC
25
N
Not to be connected
NC
26
N
Not to be connected
CLK16P
27
A
Crystal oscillator input/output
CLK16N
28
A
Crystal oscillator input/output
Default functionality: Crystal oscillator (or divided) clock output
Can be programmed to be used as a general purpose I/O pin
Default functionality: Transmit and receive interrupt
Can be programmed to be used as a general purpose I/O pin
All digital inputs are Schmitt trigger inputs; digital input
and output levels are LVCMOS/LVTTL compatible and 5 V
tolerant.
The center pad of the QFN28 package should be
connected to GND.
A = analog signal
I = digital input signal
O = digital output signal
I/O = digital input/output signal
N = not to be connected
P = power or ground
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AX5051
CLK16N
CLK16P
NC
NC
VREG
NC
GND
Pinout Drawing
28
27
26
25
24
23
22
NC
NC 1
21
VDD 2
20
VDD_IO
GND 3
19
IRQ
18
TST3
AX5051
ANTP 4
CLK
NC
8
9
10
11
12
13
14
SEL
15
SYSCLK
VDD 7
GND
MISO
RESET_N
16
TST2
MOSI
GND 6
TST1
ANTN 5
17
Figure 2. Pinout Drawing (Top View)
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AX5051
SPECIFICATIONS
Table 2. ABSOLUTE MAXIMUM RATINGS
Symbol
Description
Condition
Min
Max
Units
−0.5
5.5
V
mA
VDD_IO
Supply voltage
IDD
Supply current
100
Ptot
Total power consumption
800
mW
PI
Absolute maximum input power at receiver input
15
dBm
II1
DC current into any pin except ANTP, ANTN
−10
10
mA
II2
DC current into pins ANTP, ANTN
−100
100
mA
IO
Output current
40
mA
Via
Input voltage ANTP, ANTN pins
5.5
V
−0.5
Input voltage digital pins
−0.5
5.5
V
−2000
2000
V
Operating temperature
−40
85
°C
Tstg
Storage temperature
−65
150
°C
Tj
Junction temperature
150
°C
Ves
Electrostatic handling
Tamb
HBM
Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality
should not be assumed, damage may occur and reliability may be affected.
1. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
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AX5051
DC Characteristics
Table 3. SUPPLIES
Symbol
Description
Condition
TAMB
Operational ambient temperature
VDD_IO
I/O and voltage regulator supply voltage
VREG
Internally regulated supply voltage
Min
Typ
Max
Units
−40
27
85
°C
RX operation or TX operation
up to 4 dBm output power
2.2
3.0
3.6
V
TX operation up to 16 dBm
output power
2.4
3.0
3.6
V
Power−down mode
PWRMODE=0x00
1.7
All other power modes
2.1
2.5
V
2.8
V
VREGdroptyp
Regulator voltage drop
RX operation or TX operation
up to 4 dBm output power
50
mV
VREGdropmax
Regulator voltage drop at maximum internal
current consumption
TX mode with 16 dBm output
power
300
mV
IPDOWN
Power−down current
PWRMODE = 0x00
0.5
mA
IRX−HS
Current consumption RX
High sensitivity mode:
VCO_I = 001; REF_I = 011
Bit rate 10 kbit/s
19
mA
IRX−LP
Current consumption RX
Low power mode:
VCO_I = 001; REF_I = 101
Bit rate 10 kbit/s
17
mA
ITX
Current consumption TX
VCO_I = 001; REF_I = 011; LOCURST = 1,
(Note 1)
868 MHz, 15 dBm
45
mA
433 MHz, 15 dBm
45
TXvarvdd
Variation of output power over voltage
VDD > 2.5 V
± 0.5
dB
TXvartemp
Variation of output power over temperature
VDD > 2.5 V
± 0.5
dB
1. The PA voltage is regulated to 2.5 V. Between 2.2 V and 2.55 V VDD_IO a drop of 1 dBm of output power is visible.
Note on Current Consumption in TX Mode
To achieve best output power the matching network has to
be optimized for the desired output power and frequency. As
a rule of thumb a good matching network produces about
50% efficiency with the AX5051 power amplifier although
over 90% are theoretically possible. A typical matching
network has between 1 dB and 2 dB loss (Ploss).
The current consumption can be calculated as
I TX[mA] +
1
PA efficiency
ǒ
10
P out[dBm])P
10
loss
Ǔ B 2.5V ) I
[dB]
offset
Ioffset is about 12 mA for the VCO at 400−470 MHz and
11 mA for 800−940 MHz. The following table shows
calculated current consumptions versus output power for
Ploss = 1 dB, PAefficiency = 0.5 and Ioffset= 11 mA at 868 MHz.
Table 4.
Pout [dBm]
I [mA]
0
13.0
1
13.2
2
13.6
3
14.0
4
14.5
5
15.1
6
16.0
7
17.0
8
18.3
9
20.0
10
22.0
11
24.6
12
27.96
13
32.1
14
37.3
15
43.8
The AX5051 power amplifier runs from the regulated
VDD supply and not directly from the battery. This has the
advantage that the current and output power do not vary
much over supply voltage and temperature from 2.55 V to
3.6 V supply voltage. Between 2.55 V and 2.2 V a drop of
about 1 dB in output power occurs.
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AX5051
Table 5. LOGIC
Symbol
Description
Condition
Min
Typ
Max
Units
Digital Inputs
VT+
Schmitt trigger low to high threshold point
1.9
VT−
Schmitt trigger high to low threshold point
1.2
VIL
Input voltage, low
VIH
Input voltage, high
2.0
IL
Input leakage current
−10
V
V
0.8
V
V
10
mA
Digital Outputs
IOH
Output Current, high
VOH = 2.4 V
IOL
Output Current, low
VOL = 0.4 V
IOZ
Tri−state output leakage current
4
4
−10
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mA
mA
10
mA
AX5051
AC Characteristics
Table 6. CRYSTAL OSCILLATOR
Symbol
Description
Condition
Min
Typ
Max
Units
15.5
16
25
MHz
fXTAL
Crystal frequency
Notes 1, 3
gmosc
Transconductance oscillator
XTALOSCGM = 0000
1
XTALOSCGM = 0001
2
XTALOSCGM = 0010
default
3
XTALOSCGM = 0011
4
XTALOSCGM = 0100
5
XTALOSCGM = 0101
6
XTALOSCGM = 0110
6.5
XTALOSCGM = 0111
7
XTALOSCGM = 1000
7.5
XTALOSCGM = 1001
8
XTALOSCGM = 1010
8.5
XTALOSCGM = 1011
9
XTALOSCGM = 1100
9.5
XTALOSCGM = 1101
10
XTALOSCGM = 1110
10.5
XTALOSCGM = 1111
11
XTALCAP = 000000 default
2
XTALCAP = 111111
33
Cosc
Programmable tuning capacitors at pins
CLK16N and CLK16P
Cosc−lsb
Programmable tuning capacitors,
increment per LSB of XTALCAP
fext
External clock input
RINosc
Input DC impedance
mS
pF
0.5
Notes 2, 3
15.5
10
15
pF
25
MHz
kW
1. Tolerances and start−up times depend on the crystal used. Depending on the RF frequency and channel spacing the IC must be calibrated
to the exact crystal frequency using the readings of the register TRKFREQ.
2. If an external clock is used, it should be input via an AC coupling at pin CLK16P with the oscillator powered up and XTALCAP = 000000
3. Lower frequencies than 15.5 MHz or higher frequencies than 25 MHz can be used. However, not all typical RF frequencies can then be
generated.
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AX5051
Table 7. RF FREQUENCY GENERATION SUBSYSTEM (SYNTHESIZER)
Symbol
Description
Condition
Min
Typ
Max
fREF
Reference frequency
Note 1
frange_hi
Frequency range
BANDSEL = 0
800
940
BANDSEL = 1
400
470
frange_low
fRESO
Frequency resolution
BW1
Synthesizer loop bandwidth
VCO current: VCOI = 001
16
24
1
100
BW2
Loop filter configuration: FLT = 01
Charge pump current: PLLCPI = 001
50
BW3
Loop filter configuration: FLT = 11
Charge pump current: PLLCPI = 010
200
BW4
Loop filter configuration: FLT = 10
Charge pump current: PLLCPI = 010
500
Loop filter configuration: FLT = 01
Charge pump current: PLLCPI = 010
15
Loop filter configuration: FLT = 01
Charge pump current: PLLCPI = 001
30
Tset3
Loop filter configuration: FLT = 11
Charge pump current: PLLCPI = 010
7
Tset4
Loop filter configuration: FLT = 10
Charge pump current: PLLCPI = 010
3
Loop filter configuration: FLT = 01
Charge pump current: PLLCPI = 010
25
Loop filter configuration: FLT = 01
Charge pump current: PLLCPI = 001
50
Tstart3
Loop filter configuration: FLT = 11
Charge pump current: PLLCPI = 010
12
Tstart4
Loop filter configuration: FLT = 10
Charge pump current: PLLCPI = 010
5
Tset2
Tstart1
Tstart2
PN8681
Synthesizer settling time for
1 MHz step as typically
required for RX/TX switching
VCO current: VCO_I = 001
Synthesizer start−up time if
crystal oscillator and
reference are running
VCO current: VCO_I = 001
Synthesizer phase noise
Loop filter configuration:
FLT = 01
Charge pump current:
PLLCPI = 010
VCO current: VCO_I = 001
PN4331
PN8682
PN4332
Synthesizer phase noise
Loop filter configuration:
FLT = 01
Charge pump current:
PLLCPI = 001
VCO current: VCO_I = 001
868 MHz, 50 kHz from carrier
−85
868 MHz, 100 kHz from carrier
−90
868 MHz, 300 kHz from carrier
−100
868 MHz, 2 MHz from carrier
−110
433 MHz, 50 kHz from carrier
−90
433 MHz, 100 kHz from carrier
−95
433 MHz, 300 kHz from carrier
−105
433 MHz, 2 MHz from carrier
−115
868 MHz, 50 kHz from carrier
−80
868 MHz, 100 kHz from carrier
−90
868 MHz, 300 kHz from carrier
−105
868 MHz, 2 MHz from carrier
−115
433 MHz, 50 kHz from carrier
−90
433 MHz, 100 kHz from carrier
−95
433 MHz, 300 kHz from carrier
−110
433 MHz, 2 MHz from carrier
−122
1. ASK, PSK and 0.1−200 kbps FSK with 16 MHz crystal, 200−350 kbps FSK with 24 MHz crystal.
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MHz
MHz
Hz
Loop filter configuration: FLT = 01
Charge pump current: PLLCPI = 010
Tset1
Units
kHz
ms
ms
dBc/Hz
dBc/Hz
AX5051
Table 8. TRANSMITTER
Symbol
SBR
Description
Condition
Signal bit rate
Max
Units
ASK
Min
1
Typ
600
kbps
PSK
10
600
FSK, (Note 2)
1
350
802.15.4 (DSSS)
ASK and PSK
1
40
802.15.4 (DSSS)
FSK
1
16
PTX868
Transmitter power @ 868 MHz
TXRNG = 0000
LOCURST = 1
15
dBm
PTX433
Transmitter power @ 433 MHz
TXRNG = 1111
LOCURST = 1
16
dBm
PTX868−harm2
Emission @ 2nd harmonic
(Note 1)
−50
dBc
PTX868−harm3
Emission @
3rd
harmonic
−55
1. Additional low−pass filtering was applied to the antenna interface, see section Application Information.
2. 1 − 200 kbps with 16 MHz crystal, 200 − 350 kbps with 24 MHz crystal
Table 9. RECEIVER
Input Sensitivity in dBm TYP. at SMA Connector for BER = 10−3 (433 or 868 MHz)
FSK h = 8
FSK h = 16
1.2
−115
−116
2
−115
−115
Datarate [kbps]
ASK
FSK h = 1
10
−103
100
−97
−103
200
−94
−100
600
−90
FSK h = 4
−109
−98
PSK
−110
−104
−100
−98
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AX5051
Table 10.
Symbol
SBR
Description
Signal bit rate
Max
Units
ASK
Condition
Min
1
Typ
600
kbps
PSK
10
600
FSK
1
350
802.15.4 (DSSS)
ASK and PSK
1
40
802.15.4 (DSSS)
FSK
1
16
IL
Maximum input level
CP1dB
Input referred compression point
IIP3
Input referred IP3
−25
RSSIR
RSSI control range
85
dB
RSSIS1
RSSI step size
Before digital channel filter; calculated
from register AGCCOUNTER
0.625
dB
RSSIS2
RSSI step size
Behind digital channel filter; calculated
from registers AGCCOUNTER,
TRKAMPL
0.1
dB
SEL868
Adjacent channel suppression
FSK 50 kbps,
(Notes 1 & 2)
18
dB
FSK 100 kbps,
(Notes 1 & 3)
16
PSK 200 kbps,
(Notes 1 & 4)
17
FSK 100 kbps,
(Note 5)
38
Alternate channel suppression
Adjacent channel suppression
Alternate channel suppression
Adjacent channel suppression
Alternate channel suppression
BLK868
Blocking at ± 1 MHz offset
Blocking at − 2 MHz offset
IMRR868
−20
2 tones separated by 100 kHz
−35
dBm
dBm
19
dB
30
dB
28
dB
40
Blocking at ± 10 MHz offset
60
Blocking at ± 100 MHz offset
82
Image rejection
30
1. Interferer/Channel @ BER = 10−3, channel level is +10 dB above the typical sensitivity, the interfering signal is a random data signal (except
PSK200); both channel and interferer are modulated without shaping
2. FSK 50 kbps: 868 MHz, 200 kHz channel spacing, 25 kHz deviation, programming as recommended in Programming Manual
3. FSK 100 kbps: 868 MHz, 400 kHz channel spacing, 50 kHz deviation , programming as recommended in Programming Manual
4. PSK 200 kbps: 868 MHz, 400 kHz channel spacing, programming as recommended in Programming Manual, interfering signal is a constant
wave
5. Channel/Blocker @ BER = 10−3, channel level is +10 dB above the typical sensitivity, the blocker signal is a constant wave; channel signal
is modulated without shaping, the image frequency lies 2 MHz above the wanted signal
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AX5051
Table 11. SPI TIMING
Symbol
Description
Condition
Min
Typ
Max
Units
Tss
SEL falling edge to CLK rising edge
10
ns
Tsh
CLK falling edge to SEL rising edge
10
ns
Tssd
SEL falling edge to MISO driving
0
10
ns
Tssz
SEL rising edge to MISO high−Z
0
10
ns
Ts
MOSI setup time
10
Th
MOSI hold time
10
Tco
CLK falling edge to MISO output
Tck
CLK period
Tcl
Tch
ns
ns
10
(Note 1)
ns
50
ns
CLK low duration
40
ns
CLK high duration
40
ns
1. For SPI access during power−down mode the period should be relaxed to 100 ns.
For a figure showing the SPI timing parameters see section Serial Peripheral Interface (SPI).
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AX5051
CIRCUIT DESCRIPTION
The voltage regulator requires a 1 mF low ESR capacitor
at pin VREG.
In power−down mode the voltage regulator typically
outputs 1.7 V at VREG, if it is powered−up its output rises
to typically 2.5 V. At device power−up the regulator is in
power−down mode.
The voltage regulator must be powered−up before receive
or transmit operations can be initiated. This is handled
automatically when programming the device modes via the
PWRMODE register.
Register VREG contains status bits that can be read to
check if the regulated voltage is above 1.3 V or 2.3 V, sticky
versions of the bits are provided that can be used to detect
low power events (brown−out detection).
The AX5051 is a true single chip low−power CMOS
transceiver primarily for use in SRD bands. The on−chip
transceiver consists of a fully integrated RF front−end with
modulator, and demodulator. Base band data processing is
implemented in an advanced and flexible communication
controller that enables user−friendly communication via the
SPI interface.
AX5051 can be operated from 2.2 V to 3.6 V power
supply over a temperature range from −40°C to 85°C, it
consumes 11 − 45 mA for transmitting depending on the
output power, 19 mA for receiving in high sensitivity mode
and 18 mA for receiving in low power mode.
The AX5051 features make it an ideal interface for
integration into various battery powered SRD solutions such
as ticketing or as transceiver for telemetric applications e.g.
in sensors. As primary application, the transceiver is
intended for UHF radio equipment in accordance with the
European Telecommunication Standard Institute (ETSI)
specification EN 300 220−1 and the US Federal
Communications Commission (FCC) standard CFR47, part
15. The use of AX5051 in accordance to FCC Par 15.247,
allows for improved range in the 915 MHz band.
Additionally AX5051 is compatible with the low frequency
standards of 802.15.4 (ZigBee). It therefore incorporates a
DSSS engine, which spreads data on the transmitter and
despreads data for the receiver. Spreading and despreading
is possible on all data rates and modulation schemes. The net
transfer rate is reduced by a factor of 15 in this case. For
802.15.4 either 600 or 300 kbps modes have to be chosen.
The AX5051 sends and receives data via the SPI port in
frames. This standard operation mode is called Frame Mode.
Pre and post ambles as well as checksums can be generated
automatically. Interrupts control the data flow between a
controller and the AX5051.
The AX5051 behaves as a SPI slave interface.
Configuration of the AX5051 is also done via the SPI
interface.
AX5051 supports any data rate from 1 kbps to 350 kbps
for FSK and MSK and from 1 kbps for 600 kbps for ASK and
10 kbps to 600 kbps PSK. To achieve optimum performance
for specific data rates and modulation schemes several
register settings to configure the AX5051 are necessary, they
are outlined in the following, for details see the AX5051
Programming Manual.
The receiver supports multi−channel operation for all data
rates and modulation schemes.
Crystal Oscillator
The on−chip crystal oscillator allows the use of an
inexpensive quartz crystal as the RF generation subsystem’s
timing reference. Although a wider range of crystal
frequencies can be handled by the crystal oscillator circuit,
it is recommended to use 16 MHz as reference frequency for
ASK and PSK modulations independent of the data rate. For
FSK it is recommended to use a 16 MHz crystal for data rates
below 200 kbps and 24 MHz for data rates above 200 kbps.
The oscillator circuit is enabled by programming the
PWRMODE register. At power−up it is not enabled.
To adjust the circuit’s characteristics to the quartz crystal
being used without using additional external components,
both the transconductance and the tuning capacitance of the
crystal oscillator can be programmed.
The transconductance is programmed via register bits
XTALOSCGM[3:0] in register XTALOSC.
The integrated programmable tuning capacitor bank
makes it possible to connect the oscillator directly to pins
CLK16N and CLK16P without the need for external
capacitors. It is programmed using bits XTALCAP[5:0] in
register XTALCAP.
To synchronize the receiver frequency to a carrier signal,
the oscillator frequency could be tuned using the capacitor
bank however, the recommended method to implement
frequency synchronization is to make use of the high
resolution RF frequency generation sub−system together
with the Automatic Frequency Control, both are described
further down.
Alternatively a single ended reference (TXCO, CXO)
may be used. The CMOS levels should be applied to
CLK16P via an AC coupling with the crystal oscillator
enabled.
Voltage Regulator
The AX5051 uses an on−chip voltage regulator to create
a stable supply voltage for the internal circuitry at pin VREG
from the primary supply VDD_IO. All VDD pins of the
device must be connected to VREG. The antenna pins
ANTP and ANTN must be DC biased to VREG. The I/O
level of the digital pins is VDD_IO.
SYSCLK Output
The SYSCLK pin outputs the reference clock signal
divided by a programmable integer. Divisions from 1 to
2048 are possible. For divider ratios > 1 the duty cycle is
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AX5051
The synthesizer loop bandwidth can be programmed. This
serves three purposes:
1. Start−up time optimization, start−up is faster for
higher synthesizer loop bandwidths.
2. TX spectrum optimization, phase−noise at
300 kHz to 1 MHz distance from the carrier
improves with lower synthesizer loop bandwidths.
3. Adaptation of the bandwidth to the data−rate. For
transmission of FSK and MSK it is required that
the synthesizer bandwidth must be in the order of
the data−rate.
50%. Bits SYSCLK[3:0] in the PINCFG1 register set the
divider ratio. The SYSCLK output can be disabled.
Outputting a frequency that is identical to the IF frequency
(default 1 MHz) on the SYSCLK pin is not recommended
during receive operation, since it requires extensive
decoupling on the PCB to avoid interference.
Power−on−reset (POR) and RESET_N Input
AX5051 has an integrated power−on−reset block. No
external POR circuit or signal at the RESET_N pin is
required, prior to POR the RESET_N pin is disabled.
After POR the AX5051 can be reset in two ways:
1. By SPI accesses: the bit RST in the PWRMODE
register is toggled.
2. Via the RESET_N pin: A low pulse is applied at
the RESET_N pin. With the rising edge of
RESET_N the device goes into its operational
state.
After POR or reset all registers are set to their default
values.
If the RESET_N pin is not used it must be tied to
VDD_IO.
VCO
An on−chip VCO converts the control voltage generated
by the charge pump and loop filter into an output frequency.
This frequency is used for transmit as well as for receive
operation. The frequency can be programmed in 1 Hz steps
in the FREQ registers. For operation in the 433 MHz band,
the BANDSEL bit in the PLLLOOP register must be
programmed.
VCO Auto−Ranging
The AX5051 has an integrated auto−ranging function,
which allows to set the correct VCO range for specific
frequency generation subsystem settings automatically.
Typically it has to be executed after power−up. The function
is initiated by setting the RNG_START bit in the
PLLRANGING register. The bit is readable and a 0 indicates
the end of the ranging process. The RNGERR bit indicates
the correct execution of the auto−ranging.
RF Frequency Generation Subsystem
The RF frequency generation subsystem consists of a
fully integrated synthesizer, which multiplies the reference
frequency from the crystal oscillator to get the desired RF
frequency. The advanced architecture of the synthesizer
enables frequency resolutions of 1 Hz, as well as fast settling
times of 5 – 50 ms depending on the settings (see section:
AC Characteristics). Fast settling times mean fast start−up
and fast RX/TX switching, which enables low−power
system design.
For receive operation the RF frequency is fed to the mixer,
for transmit operation to the power−amplifier.
The frequency must be programmed to the desired carrier
frequency. The RF frequency shift by the IF frequency that
is required for RX operation, is automatically set when the
receiver is activated and does not need to be programmed by
the user. The default IF frequency is 1 MHz. It can be
programmed to other values. Changing the IF−frequency
and thus the center frequency of the digital channel filter can
be used to adapt the blocking performance of the device to
specific system requirements.
Loop Filter and Charge Pump
The AX5051 internal loop filter configuration together
with the charge pump current sets the synthesizer loop band
width. The loop−filter has three configurations that can be
programmed via the register bits FLT[1:0] in register
PLLLOOP, the charge pump current can be programmed
using register bits PLLCPI[1:0] also in register PLLLOOP.
Synthesizer bandwidths are typically 50 – 500 kHz
depending on the PLLLOOP settings, for details see the
section: AC Characteristics.
Registers
Table 12. REGISTERS
Register
PLLLOOP
Bits
Purpose
FLT[1:0]
Synthesizer loop filter bandwidth, recommended usage is to increase the bandwidth for faster
settling time, bandwidth increases of factor 2 and 5 are possible.
PLLCPI[2:0]
Synthesizer charge pump current, recommended usage is to decrease the bandwidth (and
improve the phase−noise) for low data−rate transmissions.
BANDSEL
Switches between 868 MHz / 915 MHz and 433 MHz bands
FREQ
Programming of the carrier frequency
IFFREQHI, IFFREQLO
Programming of the IF frequency
PLLRANGING
Initiate VCO auto−ranging and check results
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14
AX5051
RF Input and Output Stage (ANTP/ANTN)
Analog IF Filter
The AX5051 uses fully differential antenna pins. RX/TX
switching is handled internally; an external RX/TX switch
is not required.
The mixer is followed by a complex band−pass IF filter,
which suppresses the down−mixed image while the wanted
signal is amplified. The center frequency of the filter is
1 MHz, with a pass−band width of 1 MHz. The RF
frequency generation subsystem must be programmed in
such a way that for all possible modulation schemes the IF
frequency spectrum fits into the pass−band of the analog
filter.
LNA
The LNA amplifies the differential RF signal from the
antenna and buffers it to drive the I/Q mixer. An external
matching network is used to adapt the antenna impedance to
the IC impedance. A DC feed to the regulated supply voltage
VREG must be provided at the antenna pins. For
recommendations see section: Application Information.
Digital IF Channel Filter and Demodulator
The digital IF channel filter and the demodulator extract
the data bit−stream from the incoming IF signal. They must
be programmed to match the modulation scheme as well as
the data rate. Inaccurate programming will lead to loss of
sensitivity.
The channel filter offers bandwidths of 40 kHz up to
600 kHz.
For detailed instructions how to program the digital
channel filter and the demodulator see the AX5051
Programming Manual, an overview of the registers involved
is given in the following table. The register setups typically
must be done once at power−up of the device.
I/Q Mixer
The RF signal from the LNA is mixed down to an IF of
typically 1 MHz. I− and Q−IF signals are buffered for the
analog IF filter.
PA
In TX mode the PA drives the signal generated by the
frequency generation subsystem out to the differential
antenna terminals. The output power of the PA is
programmed via bits TXRNG[3:0] in the register TXPWR.
Output power as well as harmonic content will depend on the
external impedance seen by the PA, recommendations are
given in the section: Application Information.
Table 13. REGISTERS
Register
Remarks
CICDEC
This register programs the bandwidth of the digital channel filter.
DATARATEHI, DATARATELO
These registers specify the receiver bit rate, relative to the channel filter bandwidth.
TMGGAINHI, TMGGAINLO
These registers specify the aggressiveness of the receiver bit timing recovery. More aggressive
settings allow the receiver to synchronize with shorter preambles, at the expense of more timing
jitter and thus a higher bit error rate at a given signal−to−noise ratio.
MODULATION
This register selects the modulation to be used by the transmitter and the receiver, i.e. whether
ASK, PSK , FSK, MSK or OQPSK should be used.
PHASEGAIN, FREQGAIN,
FREQGAIN2, AMPLGAIN
These registers control the bandwidth of the phase, frequency offset and amplitude tracking loops.
Recommended settings are provided in the Programming Manual.
AGCATTACK, AGCDECAY
These registers control the AGC (automatic gain control) loop slopes, and thus the speed of gain
adjustments. The faster the bit rate, the faster the AGC loop should be. Recommended settings
are provided in the Programming Manual.
TXRATE
These registers control the bit rate of the transmitter.
FSKDEV
These registers control the frequency deviation of the transmitter in FSK mode. The receiver does
not explicitly need to know the frequency deviation, only the channel filter bandwidth has to be set
wide enough for the complete modulation to pass.
Encoder
The encoder is located between the Framing Unit, the
Demodulator and the Modulator. It can optionally transform
the bit−stream in the following ways:
• It can invert the bit stream.
• It can perform differential encoding. This means that a
zero is transmitted as no change in the level, and a one
is transmitted as a change in the level. Differential
encoding is useful for PSK, because PSK transmissions
can be received either as transmitted or inverted, due to
•
•
the uncertainty of the initial phase. Differential
encoding / decoding removes this uncertainty.
It can perform Manchester encoding. Manchester
encoding ensures that the modulation has no DC
content and enough transitions (changes from 0 to 1 and
from 1 to 0) for the demodulator bit timing recovery to
function correctly, but does so at a doubling of the data
rate.
It can perform Spectral Shaping. Spectral Shaping
removes DC content of the bit stream, ensures
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15
AX5051
meta information consists of packet begin / end information
and the result of CRC checks.
The AX5051 contains one FIFO. Its direction is switched
depending on whether transmit or receive mode is selected.
The FIFO can be operated in polled or interrupt driven
modes. In polled mode, the micro−controller must
periodically read the FIFO status register or the FIFO count
register to determine whether the FIFO needs servicing.
In interrupt mode EMPTY, NOT EMPTY, FULL, NOT
FULL and programmable level interrupts are provided. The
AX5051 signals interrupts by asserting (driving high) its
IRQ line. The interrupt line is level triggered, active high.
Interrupts are acknowledged by removing the cause for the
interrupt, i.e. by emptying or filling the FIFO.
Basic FIFO status (EMPTY, FULL, Overrun, Under−run,
and the top two bits of the top FIFO word) are also provided
during each SPI access on MISO while the micro−controller
shifts out the register address on MOSI. See the SPI interface
section for details. This feature significantly reduces the
number of SPI accesses necessary during transmit and
receive.
transitions for the demodulator bit timing recovery, and
makes sure that the transmitted spectrum does not have
discrete lines even if the transmitted data is cyclic. It
does so without adding additional bits, i.e. without
changing the data rate. Spectral Shaping uses a
self−synchronizing feedback shift register.
The encoder is programmed using the register
ENCODING, details and recommendations on usage are
given in the AX5051 Programming Manual.
Framing and FIFO
Most radio systems today group data into packets. The
framing unit is responsible for converting these packets into
a bit−stream suitable for the modulator, and to extract
packets from the continuous bit−stream arriving from the
demodulator.
The Framing unit supports four different modes:
• HDLC
• Raw
• Raw with Preamble Match
• 802.15.4 Compliant
HDLC Mode
NOTE: HDLC mode follows High−Level Data Link
Control (HDLC, ISO 13239) protocol.
HDLC Mode is the main framing mode of the AX5051. In
this mode, the AX5051 performs automatic packet
delimiting, and optional packet correctness check by
inserting and checking a cyclic redundancy check (CRC)
field.
The packet structure is given in the following table.
The micro−controller communicates with the framing
unit through a 4 level × 10 bit FIFO. The FIFO decouples
micro−controller timing from the radio (modulator and
demodulator) timing. The bottom 8 bits of the FIFO contain
transmit or receive data. The top 2 bit are used to convey
meta information in HDLC and 802.15.4 modes. They are
unused in Raw and Raw with Preamble Match modes. The
Table 14.
Flag
Address
Control
Information
FCS
(Optional Flag)
8 bit
8 bit
8 or 16 bit
Variable length, 0 or more bits in multiples of 8
16 / 32 bit
8 bit
anything until it detects a user programmable bit pattern
(called the preamble) in the receive bit−stream. When it
detects the preamble, it aligns the de−serialization to it.
The preamble can be between 4 and 32 bits long.
HDLC packets are delimited with flag sequences of
content 0x7E.
In AX5051 the meaning of address and control is user
defined. The Frame Check Sequence (FCS) can be
programmed to be CRC−CCITT, CRC−16 or CRC−32.
The receiver checks the CRC, the result can be retrieved
from the FIFO, the CRC is appended to the received data.
For details on implementing a HDLC communication see
the AX5051 Programming Manual.
802.15.4 (ZigBee) DSSS
802.15.4 uses binary phase shift keying (PSK) with
300 kbit/s (868 MHz band) or 600 kbit/s (915 MHz band) on
the radio. The usable bit rate is only a 15th of the radio bit
rate, however. A spreading function in the transmitter
expands the user bit rate by a factor of 15, to make the
transmission more robust. The despreader function of the
receiver undoes that.
In 802.15.4 mode, the AX5051 framing unit performs the
spreading and despreading function according to the
802.15.4 specification. In receive mode, the framing unit
will also automatically search for the 802.15.4 preamble,
meaning that no interrupts will have to be serviced by the
micro−controller until a packet start is detected.
Raw Mode
In Raw mode, the AX5051 does not perform any packet
delimiting or byte synchronization. It simply serializes
transmit bytes and de−serializes the received bit−stream and
groups it into bytes.
This mode is ideal for implementing legacy protocols in
software.
Raw Mode with Preamble Match
Raw mode with preamble match is similar to raw mode.
In this mode, however, the receiver does not receive
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16
AX5051
be used as soon as the RF frequency generation
sub−system has been programmed.
2. RSSI behind the digital IF channel filter.
The demodulator also provides amplitude
information in the TRK_AMPLITUDE register.
By combining both the AGCCOUNTER and the
TRK_AMPLITUDE registers, a high resolution
(better than 0.1 dB) RSSI value can be computed
at the expense of a few arithmetic operations on
the micro−controller. Formulas for this
computation can be found in the AX5051
Programming Manual.
The 802.15.4 is a universal DSSS mode, which can be
used with any modulation or data rate as long as it does not
violate the maximum data rate of the modulation being used.
Therefore the maximum DSSS data rate is 16 kbps for FSK
and 40 kbps for ASK and PSK.
RX AGC and RSSI
AX5051 features two receiver signal strength indicators
(RSSI):
1. RSSI before the digital IF channel filter.
The gain of the receiver is adjusted in order to
keep the analog IF filter output level inside the
working range of the ADC and demodulator. The
register AGCCOUNTER contains the current
value of the AGC and can be used as an RSSI. The
step size of this RSSI is 0.625 dB. The value can
Modulator
Depending on the transmitter settings the modulator
generates various inputs for the PA (see Table 15):
Table 15.
Modulation
Bit = 0
Bit = 1
Main Lobe Bandwidth
Max. Bitrate
ASK
PA off
PA on
BW = BITRATE
600 kBit/s
FSK/MSK
Df = −fdeviation
Df = +fdeviation
BW = (1 + h) ⋅BITRATE
350 kBit/s
PSK
DF = 0°
DF = 180°
BW = BITRATE
600 kBit/s
Table 16.
h
Modulation index. It is the ratio of the deviation compared to the bit−rate.
AX5051 can demodulate signals with h < 32.
fdeviation
0.5⋅h⋅BITRATE
ASK
Amplitude shift keying
FSK
Frequency shift keying
MSK
Minimum shift keying.
MSK is a special case of FSK, where h = 0.5, and therefore fdeviation = 0.25⋅BITRATE; the advantage of MSK over FSK is
that it can be demodulated more robustly.
PSK
Phase shift keying
OQPSK
Offset quadrature shift keying.
The AX5051 supports OQPSK. However, unless compatibility to an existing system is required, MSK should be preferred.
All modulation schemes are binary.
Automatic Frequency Control (AFC)
FSKMUL is the FSK oversampling factor, it depends on
the FSK bit−rate and deviation used. To determine it for a
specific case, see the AX5051 Programming Manual. For
modulations other than FSK, FSKMUL = 1.
The AX5051 has a frequency tracking register
TRKFREQ to synchronize the receiver frequency to a
carrier signal. For AFC adjustment, the frequency offset can
be computed with the following formula:
Df +
TRKFREQ
BITRATE
2 16
PWRMODE Register
FSKMUL
The PWRMODE register controls, which parts of the chip
are operating.
Table 17. PWRMODE REGISTER
PWRMODE Register
Name
Description
0000
POWERDOWN
All digital and analog functions, except the register file, are disabled. The
core supply voltage is reduced to conserve leakage power. SPI registers
are still accessible, but at a slower speed.
0.5 mA
0100
VREGON
All digital and analog functions, except the register file, are disabled. The
core voltage, however is at its nominal value for operation, and all SPI
registers are accessible at the maximum speed.
200 mA
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17
Typical Idd
AX5051
Table 17. PWRMODE REGISTER
PWRMODE Register
Name
0101
STANDBY
The crystal oscillator is powered on; receiver and transmitter are off.
650 mA
1000
SYNTHRX
The synthesizer is running on the receive frequency. Transmitter and
receiver are still off. This mode is used to let the synthesizer settle on the
correct frequency for receive.
11 mA
1001
FULLRX
1100
SYNTHTX
1101
FULLTX
Description
Typical Idd
Synthesizer and receiver are running.
17 − 19 mA
The synthesizer is running on the transmit frequency. Transmitter and
receiver are still off. This mode is used to let the synthesizer settle on the
correct frequency for transmit.
Synthesizer and transmitter are running. Do not switch into this mode
before the synthesizer has completely settled on the transmit frequency (in
SYNTHTX mode), otherwise spurious spectral transmissions will occur.
10 mA
11 − 45 mA
Table 18. A TYPICAL PWRMODE SEQUENCE FOR A TRANSMIT SESSION
Step
PWRMODE
Remarks
1
POWERDOWN
2
STANDBY
The settling time is dominated by the crystal used, typical value 3 ms.
3
SYNTHTX
The synthesizer settling time is 5 – 50 ms depending on settings, see section AC Characteristics
4
FULLTX
Data transmission
5
SYNTHTX
This step must be programmed after FULLTX mode, or the device will not enter
POWERDOWN or STANDBY mode.
6
POWERDOWN
Table 19. A TYPICAL PWRMODE SEQUENCE FOR A RECEIVE SESSION
Step
PWRMODE [3:0]
Remarks
1
POWERDOWN
2
STANDBY
The settling time is dominated by the crystal used, typical value 3 ms.
3
SYNTHRX
The synthesizer settling time is 5 – 50 ms depending on settings, see section AC Characteristics
4
FULLRX
Data reception
5
POWERDOWN
Serial Peripheral Interface
Figure 3 shows a write/read access to the interface. The
data stream is built of an address byte including read/write
information and a data byte. Depending on the R_N/W bit
and address bits A[6..0], data D[7..0] can be written via
MOSI or read at the pin MISO.
R_N/W = 0 means read mode, R_N/W = 1 means write
mode.
The read sequence starts with 7 bits of status information
S[6..0] followed by 8 data bits.
The status bits contain the following information:
The AX5051 can be programmed via a four wire serial
interface according SPI using the pins CLK, MOSI, MISO
and SEL. Registers for setting up the AX5051 are
programmed via the serial peripheral interface in all device
modes.
When the interface signal SEL is pulled low, a 16−bit
configuration data stream is expected on the input signal pin
MOSI, which is interpreted as D0...D7, A0...A6, R_N/W.
Data read from the interface appears on MISO.
Table 20.
S6
S5
S4
S3
S2
S1
S0
PLL LOCK
FIFO OVER
FIFO UNDER
FIFO FULL
FIFO EMPTY
FIFOSTAT(1)
FIFOSTAT(0)
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18
AX5051
SPI Timing
Tss
Tck TchTcl
Tsh
Ts Th
SS
SCK
MOSI
R/ W
MISO
Tssd
A6
A5
A4
A3
A2
A1
A0
D7
D6
D5
D4
D3
D2
D1
D0
S6
S5
S4
S3
S2
S1
S0
D7
D6
D5
D4
D3
D2
D1
D0
Tco
Tssz
Figure 3. Serial Peripheral Interface Timing
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19
AX5051
REGISTER BANK DESCRIPTION
This section describes the bits of the register bank in
detail. The registers are grouped by functional block to
facilitate programming.
No checks are made whether the programmed
combination of bits makes sense! Bit 0 is always the LSB.
NOTES: Whole registers or register bits marked as
reserved should be kept at their default values.
All addresses not documented here must not be
accessed, neither in reading nor in writing.
Table 21. CONTROL REGISTER MAP
Bit
Addr
Name
Dir
7
Reset
6
5
4
3
2
1
0
Description
Revision & Interface Probing
0
REVISION
R
00010100
SILICONREV(7:0)
Silicon Revision
1
SCRATCH
RW
11000101
SCRATCH(7:0)
Scratch Register
RW
0−−−0000
RST
−
−
−
PWRMODE(3:0)
Power Mode
RW
−−−−0010
−
−
−
−
XTALOSCGM(3:0)
GM of Crystal
Oscillator
FIFO
OVER
FIFO
UNDER
FIFO FULL FIFO
EMPTY
Operating Mode
2
PWRMODE
Crystal Oscillator, Part 1
3
XTALOSC
FIFO, Part 1
4
FIFOCTRL
RW
−−−−−−11
FIFOSTAT(1:0)
5
FIFODATA
RW
−−−−−−−−
FIFODATA(7:0)
FIFOCMD(1:0)
FIFO Control
FIFO Data
Interrupt Control
6
IRQMASK
RW
−−000000
−
−
IRQMASK(5:0)
IRQ Mask
7
IRQREQUEST
R
−−−−−−−−
−
−
IRQREQUEST(5:0)
IRQ Request
−
−
−
IFMODE(3:0)
Interface & Pin Control
8
IFMODE
RW
−−−−0011
−
0C
PINCFG1
RW
11111000
reserved
IRQZ
reserved
SYSCLK(3:0)
0D
PINCFG2
RW
00000000
TST_PINS
IRQE
reserved
reserved
0E
PINCFG3
R
−−−−−−−−
−
−
−
SYSCLKR reserved
0F
IRQINVERSION RW
−−000000
−
−
IRQINVERSION(5:0)
Interface Mode
Must be set to
0000
Pin Configuration 1
IRQI
reserved
Pin Configuration 2
TST_PINS(1:0)
must be set to 11
IRQR
reserved
Pin Configuration 3
IRQ Inversion
Modulation & Framing
10
MODULATION
RW
−0000010
−
MODULATION(6:0)
11
ENCODING
RW
−−−−0010
−
−
−
12
FRAMING
RW
−0000000
FRMRX
HSUPP
CRCMODE(1:0)
14
CRCINIT3
RW
11111111
CRCINIT(31:24)
CRC Initialization
Data or Preamble
15
CRCINIT2
RW
11111111
CRCINIT(23:16)
CRC Initialization
Data or Preamble
16
CRCINIT1
RW
11111111
CRCINIT(15:8)
CRC Initialization
Data or Preamble
17
CRCINIT0
RW
11111111
CRCINIT(7:0)
CRC Initialization
Data or Preamble
R
−−−−−−−−
−
Modulation
−
ENC
MANCH
ENC
SCRAM
ENC
DIFF
FRMMODE(2:0)
ENC INV Encoder/Decoder
Settings
FABORT Framing settings
Voltage Regulator
1B
VREG
−
−
−
SSDS
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20
SSREG
SDS
SREG
Voltage Regulator
Status
AX5051
Table 21. CONTROL REGISTER MAP
Bit
Addr
Name
Dir
Reset
7
6
5
4
3
2
1
0
Description
Synthesizer
20
FREQ3
RW
00111001
FREQ(31:24)
Synthesizer
Frequency
21
FREQ2
RW
00110100
FREQ(23:16)
Synthesizer
Frequency
22
FREQ1
RW
11001100
FREQ(15:8)
Synthesizer
Frequency
23
FREQ0
RW
11001101
FREQ(7:0)
Synthesizer
Frequency
25
FSKDEV2
RW
00000010
FSKDEV(23:16)
FSK Frequency
Deviation
26
FSKDEV1
RW
01100110
FSKDEV(15:8)
FSK Frequency
Deviation
27
FSKDEV0
RW
01100110
FSKDEV(7:0)
FSK Frequency
Deviation
28
IFFREQHI
RW
00100000
IFFREQ(15:8)
2nd LO / IF
Frequency
29
IFFREQLO
RW
00000000
IFFREQ(7:0)
2nd LO / IF
Frequency
2C
PLLLOOP
RW
−0011101
−
reserve BANDSEL
d
PLLCPI(2:0)
2D
PLLRANGING
RW
00001000
STICK
Y
LOCK
PLL
LOCK
RNG
START
VCOR(3:0)
–
–
TXRNG(3:0)
RNGERR
FLT(1:0)
Synthesizer Loop
Filter Settings
Synthesizer VCO
Auto−Ranging
Transmitter
30
TXPWR
RW
−−−−1000
–
31
TXRATEHI
RW
00001001
TXRATE(23:16)
Transmitter Bitrate
32
TXRATEMID
RW
10011001
TXRATE(15:8)
Transmitter Bitrate
33
TXRATELO
RW
10011010
TXRATE(7:0)
34
MODMISC
RW
––––––11
–
–
–
–
–
–
–
Transmit Power
Transmitter Bitrate
reserved PTTCLK
GATE
Misc RF Flags
FIFO, Part 2
35
FIFOCOUNT
R
−−−−−−−−
−
−
−
−
−
FIFOCOUNT(2:0)
FIFO Fill state
36
FIFOTHRESH
RW
−−−−−000
−
−
−
−
−
FIFOTHRESH(2:0)
FIFO Threshold
37
FIFOCONTROL RW
2
0−−−−−00
CLEAR −
−
−
−
−
−
AGCATTACK(4:0)
AGC Attack
reserved
AGCDECAY(4:0)
AGC Decay
STOPONERR(1:0) Additional FIFO
control
Receiver
3A
AGCATTACK
RW
00010110
−
3B
AGCDECAY
RW
0–010011
reserved –
3C
AGCCOUNTER R
––––––––
AGCCOUNTER(7:0)
3D
CICSHIFT
R
−−000100
−
−
reseved
3F
CICDEC
RW
00000100
−
−
CICDEC(5:0)
40
DATARATEHI
RW
00011010
DATARATE(15:8)
Datarate
41
DATARATELO
RW
10101011
DATARATE(7:0)
Datarate
42
TMGGAINHI
RW
00000000
TIMINGGAIN(15:8)
Timing Gain
43
TMGGAINLO
RW
11010101
TIMINGGAIN(7:0)
Timing Gain
44
PHASEGAIN
RW
00––0011
reserved
45
FREQGAIN
RW
00001010
reserved
46
FREQGAIN2
RW
––––1010
–
−
–
–
–
AGC Current Value
CICSHIFT(4:0)
CIC Shift Factor
CIC Decimation
Factor
–
–
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21
PHASEGAIN(3:0)
Phase Gain
FREQGAIN(3:0)
Frequency Gain
FREQGAIN2(3:0)
Frequency Gain 2
AX5051
Table 21. CONTROL REGISTER MAP
Bit
Addr
7
6
5
4
3
2
1
0
Name
Dir
Reset
47
AMPLGAIN
RW
–––00110
–
48
TRKAMPLHI
R
––––––––
TRKAMPL(15:8)
Amplitude Tracking
49
TRKAMPLLO
R
––––––––
TRKAMPL(7:0)
Amplitude Tracking
4A
TRKPHASEHI
R
––––––––
–
4B
TRKPHASELO
R
––––––––
TRKPHASE(7:0)
Phase Tracking
4C
TRKFREQHI
R
––––––––
TRKFREQ(15:8)
Frequency
Tracking
4D
TRKFREQLO
R
––––––––
TRKFREQ(7:0)
Frequency
Tracking
XTALCAP
RW
−−000000
−
−
XTALCAP(5:0)
72
PLLVCOI
RW
−−000100
−
−
reserved
7A
LOCURST
RW
00110000
LOCUR reserved
ST
7C
rEF
RW
−−100011
−
−
reserved
7D
RXMISC
RW
−−110110
−
−
reserved
–
–
–
–
reserved
–
AMPLGAIN(3:0)
Description
Amplitude Gain
TRKPHASE(11:8)
Phase Tracking
Crystal Oscillator, Part 2
4F
Crystal oscillator
tuning capacitance
Misc
VCO_I[2:0]
Synthesizer VCO
current
Must be set to 001
LOCURST
Must be set to 1
REF_I[2:0]
Reference adjust
RXIMIX(1:0)
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22
Misc RF settings
RXIMIX(1:0) must
be set to 01
AX5051
APPLICATION INFORMATION
From Power
Supply
Typical Application Diagram
1 mF
NC
GND
VREG
NC
NC
CLK16P
CLK16N
ANTENNA
NC
VDD_IO
VDD
GND
IRQ
AX5051
ANTP
VDD
CLK
SEL
MISO
SYSCLK
MOSI
GND
N2
TST1
GND
ANTN
GND
RESET_N
VREG
TO/FROM MICRO −CONTROLLER
NC
GND
Figure 4. Typical Application Diagram
It is mandatory to add 1 mF (low ESR) between VREG and
GND.
Decoupling capacitors are not all drawn. It is
recommended to add 100 nF decoupling capacitor for every
VDD and VDD_IO pin. In order to reduce noise on the
antenna inputs it is recommended to add 27 pF on the VDD
pins close to the antenna interface.
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23
AX5051
Antenna Interface Circuitry
The ANTP and ANTN pins provide RF input to the LNA
when AX5051 is in receiving mode, and RF output from the
PA when AX5051 is in transmitting mode. A small antenna
can be connected with an optional translation network. The
network must provide DC power to the PA and LNA. A
biasing to VREG is necessary.
Beside biasing and impedance matching, the proposed
networks also provide low pass filtering to limit spurious
emission.
Single−ended Antenna Interface
VREG
LC1
CC1
CB1
CM1
LT1
CT1
LB2
LF1
CF1
IC Antenna
Pins
LT2
LC2
CT2
CC2
CF2
50 W single−ended
equipment or
antenna
CB2
CM2
LB1
Optional filter stage
to suppress TX
harmonics
VREG
Figure 5. Structure of the Antenna Interface to 50 W Single−ended Equipment or Antenna
Table 22.
Frequency Band
LC1,2
[nH]
CC1,2
[pF]
LT1,2
[nH]
CT1,2
[pF]
CM1,2
[pF]
LB1,2
[nH]
CB1,2
[pF]
LF1
[nH]
CF1,2
[pF]
868 / 915 MHz
68
0.9
12
18
2.4
12
2.7
0W
NC
433 MHz
120
2.2
39
7.5
6.0
27
5.2
0W
NC
Voltage Regulator
applied at VDD_IO. Use VREG to supply all the VDD
supply pins.
The AX5051 has an integrated voltage regulator, which
generates a stable supply voltage VREG from the voltage
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AX5051
QFN28 PACKAGE INFORMATION
QFN28 5x5, 0.5P
CASE 485EF
ISSUE A
PIN ONE
REFERENCE
ÉÉ
ÉÉ
A
D
NOTES:
1. DIMENSIONS AND TOLERANCING PER
ASME Y14.5M, 1994.
2. CONTROLLING DIMENSION: MILLIMETERS.
3. DIMENSION b APPLIES TO PLATED
TERMINAL AND IS MEASURED BETWEEN
0.15 AND 0.30MM FROM THE TERMINAL TIP.
4. COPLANARITY APPLIES TO THE EXPOSED
PAD AS WELL AS THE TERMINALS.
L
L
B
L1
DETAIL A
ALTERNATE TERMINAL
CONSTRUCTIONS
E
DIM
A
A1
A3
b
D
D2
E
E2
e
L
L1
0.15 C
0.15 C
EXPOSED Cu
A
DETAIL B
0.10 C
(A3)
A1
0.08 C
C
SIDE VIEW
NOTE 4
DETAIL A
8
28X
ÉÉ
ÇÇ
ÇÇ
TOP VIEW
MOLD CMPD
DETAIL B
ALTERNATE
CONSTRUCTION
MILLIMETERS
MIN
MAX
0.80
1.00
0.00
0.05
0.20 REF
0.18
0.30
5.00 BSC
3.45
3.75
5.00 BSC
3.45
3.75
0.50 BSC
0.35
0.45
−−−
0.15
SEATING
PLANE
RECOMMENDED
SOLDERING FOOTPRINT*
D2
5.30
15
L
28X
0.60
3.80
E2
1
1
28
22
e
BOTTOM VIEW
28X
3.80 5.30
b
0.10
M
C A B
0.05
M
C
NOTE 3
0.50
PITCH
28X
0.32
DIMENSION: MILLIMETERS
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
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25
AX5051
QFN28 Soldering Profile
Preheat
Reflow
Cooling
tP
TP
Temperature
TL
tL
TsMAX
TsMIN
ts
25°C
T25°C to Peak
Time
Figure 6. QFN28 Soldering Profile
Table 23.
Profile Feature
Pb−Free Process
Average Ramp−Up Rate
3°C/s max.
Preheat Preheat
Temperature Min
TsMIN
150°C
Temperature Max
TsMAX
200°C
Time (TsMIN to TsMAX)
ts
60 – 180 sec
Time 25°C to Peak Temperature
T25°C to Peak
8 min max.
Liquidus Temperature
TL
217°C
Time over Liquidus Temperature
tL
60 – 150 s
Peak Temperature
tp
260°C
Time within 5°C of actual Peak Temperature
Tp
20 – 40 s
Reflow Phase
Cooling Phase
Ramp−down rate
6°C/s max.
1. All temperatures refer to the top side of the package, measured on the package body surface.
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AX5051
QFN28 Recommended Pad Layout
1. PCB land and solder masking recommendations
are shown in Figure 7.
A = Clearance from PCB thermal pad to solder mask opening, 0.0635 mm minimum
B = Clearance from edge of PCB thermal pad to PCB land, 0.2 mm minimum
C = Clearance from PCB land edge to solder mask opening to be as tight as possible
to ensure that some solder mask remains between PCB pads.
D = PCB land length = QFN solder pad length + 0.1 mm
E = PCB land width = QFN solder pad width + 0.1 mm
Figure 7. PCB Land and Solder Mask Recommendations
3. For the PCB thermal pad, solder paste should be
printed on the PCB by designing a stencil with an
array of smaller openings that sum to 50% of the
QFN exposed pad area. Solder paste should be
applied through an array of squares (or circles) as
shown in Figure 8.
4. The aperture opening for the signal pads should be
between 50−80% of the QFN pad area as shown in
Figure 9.
5. Optionally, for better solder paste release, the
aperture walls should be trapezoidal and the
corners rounded.
6. The fine pitch of the IC leads requires accurate
alignment of the stencil and the printed circuit
board. The stencil and printed circuit assembly
should be aligned to within + 1 mil prior to
application of the solder paste.
7. No−clean flux is recommended since flux from
underneath the thermal pad will be difficult to
clean if water−soluble flux is used.
2. Thermal vias should be used on the PCB thermal
pad (middle ground pad) to improve thermal
conductivity from the device to a copper ground
plane area on the reverse side of the printed circuit
board. The number of vias depends on the package
thermal requirements, as determined by thermal
simulation or actual testing.
3. Increasing the number of vias through the printed
circuit board will improve the thermal
conductivity to the reverse side ground plane and
external heat sink. In general, adding more metal
through the PC board under the IC will improve
operational heat transfer, but will require careful
attention to uniform heating of the board during
assembly.
Assembly Process
Stencil Design & Solder Paste Application
1. Stainless steel stencils are recommended for solder
paste application.
2. A stencil thickness of 0.125 – 0.150 mm
(5 – 6 mils) is recommended for screening.
Figure 8. Solder Paste Application on Exposed Pad
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27
AX5051
Minimum 50% coverage
62% coverage
Maximum 80% coverage
Figure 9. Solder Paste Application on Pins
ON Semiconductor and the
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC) or its subsidiaries in the United States and/or other countries.
SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed
at www.onsemi.com/site/pdf/Patent−Marking.pdf. SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation
or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC 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 special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets
and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each
customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended,
or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which
the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or
unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and
expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim
alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable
copyright laws and is not for resale in any manner.
PUBLICATION ORDERING INFORMATION
LITERATURE FULFILLMENT:
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Phone: 303−675−2175 or 800−344−3860 Toll Free USA/Canada
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Phone: 81−3−5817−1050
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28
ON Semiconductor Website: www.onsemi.com
Order Literature: http://www.onsemi.com/orderlit
For additional information, please contact your local
Sales Representative
AX5051/D