Atmel ATA5428
UHF ASK/FSK Transceiver
DATASHEET
Features
●
Multi channel half-duplex transceiver with approximately ±2.5MHz programmable
tuning range
●
High FSK sensitivity: –106dBm at 20Kbit/s/–109.5dBm at 2.4Kbit/s (433.92MHz)
●
High ASK sensitivity: –112.5dBm at 10Kbit/s/–116.5dBm at 2.4Kbit/s (433.92MHz)
●
Low supply current: 10.5mA in RX and TX Mode (3V/TX with 5dBm)
●
Data Rate: 1 to 20Kbit/s Manchester FSK, 1 to 10Kbit/s Manchester ASK
●
ASK/FSK receiver uses a low-IF architecture with high selectivity, blocking, and low
intermodulation (typical blocking 55dB at ±750kHz/61dB at ±1.5MHz and
70dB at ±10MHz, system I1dBCP = –30dBm/system IIP3 = –20dBm)
●
226kHz/237kHz IF frequency with 30dB image rejection and 170kHz usable IF
bandwidth
●
Transmitter uses closed loop fractional-N synthesizer for FSK modulation with a
high PLL bandwidth and an excellent isolation between PLL/VCO and PA
●
Tolerances of XTAL compensated by fractional-N synthesizer with 800Hz RF
resolution
●
Integrated RX/TX-switch, single-ended RF input and output
●
RSSI (Received Signal Strength Indicator)
●
Communication to microcontroller with SPI interface working at max.500kBit/s
●
Configurable self polling and RX/TX protocol handling with FIFO-RAM buffering of
received and transmitted data
●
Five push button inputs and one wake-up input are active in power-down mode
●
integrated XTAL capacitors
●
PA efficiency: up to 38% (433.92MHz/10dBm/3V)
●
Low in-band sensitivity change of typically ±1.8dB within ±58kHz center frequency
change in the complete temperature and supply voltage range
●
Supply voltage switch, supply voltage regulator, reset generation, clock/interrupt
generation and low battery indicator for microcontroller
4841E–WIRE–03/12
●
Fully integrated PLL with low phase noise VCO, PLL loop filter and full support of multi-channel operation with arbitrary
channel distance due to fractional-N synthesizer
●
Sophisticated threshold control and quasi-peak detector circuit in the data slicer
●
Power management via different operation modes
●
433.92MHz and 868.3MHz without external VCO and PLL components
●
Inductive supply with voltage regulator if battery is empty (AUX mode)
●
Efficient XTO start-up circuit (> –1.5kΩ worst case real start-up impedance)
●
Changing of modulation type ASK/FSK and data rate without component changes
●
Minimal external circuitry requirements for complete system solution
●
Adjustable output power: 0 to 10dBm adjusted and stabilized with external resistor
●
ESD protection at all pins (1.5kV HBM, 200V MM, 1kV FCDM)
●
Supply voltage range: 2.4V to 3.6V or 4.4V to 6.6V
●
Temperature range: –40°C to +85°C
●
Small 7
×
7mm QFN48 package
Applications
●
Consumer industrial segment
●
Access control systems
●
Remote control systems
●
Alarm and telemetry systems
●
Energy metering
●
Home automation
Benefits
●
Low system cost due to very high system integration level
●
Only one crystal needed in system
●
Less demanding specification for the microcontroller due to handling of power-down mode, delivering of clock, reset, low
battery indication and complete handling of receive/transmit protocol and polling
●
Single-ended design with high isolation of PLL/VCO from PA and the power supply allows a loop antenna in the remote control
unit to surround the whole application
Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
2
1.
General Description
The ATA5428 is a highly integrated UHF ASK/FSK multi-channel half-duplex transceiver with low power consumption supplied
in a small 7 x 7mm QFN48 package. The receive part is built as a fully integrated low-IF receiver, whereas direct PLL
modulation with the fractional-N synthesizer is used for FSK transmission and switching of the power amplifier for ASK
transmission.
The device supports data rates of 1Kbit/s to 20Kbit/s (FSK) and 1Kbit/s to 10Kbit/s (ASK) in Manchester, Bi-phase and other
codes in transparent mode. The ATA5428 can be used in the 431.5MHz to 436.5MHz and in the 862MHz to 872MHz bands.
The very high system integration level results in a small number of external components needed.
Due to its blocking and selectivity performance, together with the additional 15dB to 20dB loss and the narrow bandwidth of a
typical loop antenna in a remote control unit, a bulky blocking SAW is not needed in the remote control unit. Additionally, the
building blocks needed for a typical remote control and access control system on both sides (the base and the mobile stations)
are fully integrated.
Its digital control logic with self-polling and protocol generation enables a fast challenge-response system without using a high-
performance microcontroller. Therefore, the ATA5428 contains a FIFO buffer RAM and can compose and receive the physical
messages themselves. This provides more time for the microcontroller to carry out other functions such as calculating crypto
algorithms, composing the logical messages, and controlling other devices. Therefore, a standard 4-/8-bit microcontroller
without special periphery and clocked with the CLK output of about 4.5MHz is sufficient to control the communication link. This
is especially valid for passive entry and access control systems, where within less than 100ms several challenge-response
communications with arbitration of the communication partner have to be handled.
It is hence possible to design bi-directional remote control and access control systems with a fast challenge-response crypto
function, with the same PCB board size and with the same current consumption as uni-directional remote control systems.
Figure 1-1. System Block Diagram
ATA5428
RF Transceiver
Antenna
Digital Control
Logic
Power
Supply
ATmega
44/88/168
Matching/
RF Switch
Microcontroller
interface
4 to 8
XTO
Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
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Figure 1-2. Pinning QFN48
RX_ACTIVE
T1
PWR_ON
RX_TX1
RX_TX2
NC
48 47 46 45 44 43 42 41 40 39 38 37
NC
NC
NC
RF_IN
NC
433_N868
NC
R_PWR
PWR_H
RF_OUT
NC
NC
CDEM
36
35
34
33
32
NC
T2
T3
T4
T5
1
2
3
4
5
6
7
8
9
10
11
RSSI
CS
DEM_OUT
SCK
SDI_TMDI
SDO_TMDO
CLK
IRQ
N_RESET
VSINT
NC
XTAL2
ATA5428
31
30
29
28
27
26
12
25
13 14 15 16 17 18 19 20 21 22 23 24
TEST1
DVCC
VSOUT
TEST2
NC
NC
NC
AVCC
VS1
VAUX
Table 1-1.
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Pin Description
Symbol
NC
NC
NC
RF_IN
NC
433_N868
NC
R_PWR
PWR_H
RF_OUT
NC
NC
NC
NC
NC
AVCC
VS2
VS1
Function
Not connected
Not connected
Not connected
RF input
Not connected
Selects RF input/output frequency range
Not connected
Resistor to adjust output power
Pin to select output power
RF output
Not connected
Not connected
Not connected
Not connected
Not connected
Blocking of the analog voltage supply
Power supply input for voltage range 4.4V to 6.6V
Power supply input for voltage range 2.4V to 3.6V
TXAL1
VS2
Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
4
Table 1-1.
Pin
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
Pin Description (Continued)
Symbol
VAUX
TEST1
DVCC
VSOUT
TEST2
XTAL1
XTAL2
NC
VSINT
N_RESET
IRQ
CLK
SDO_TMDO
SDI_TMDI
SCK
DEM_OUT
CS
RSSI
CDEM
RX_TX2
RX_TX1
PWR_ON
T5
T4
T3
T2
T1
RX_ACTIVE
NC
NC
GND
Function
Auxiliary supply voltage input
Test input, at GND during operation
Blocking of the digital voltage supply
Output voltage power supply for external devices
Test input, at GND during operation
Reference crystal
Reference crystal
Not connected
Microcontroller interface supply voltage
Output pin to reset a connected microcontroller
Interrupt request
Clock output to connect a microcontroller
Serial data out/transparent mode data out
Serial data in/transparent mode data in
Serial clock
Demodulator open drain output signal
Chip select for serial interface
Output of the RSSI amplifier
Capacitor to adjust the lower cut
-
off frequency data filter
GND pin to decouple LNA in TX mode
Switch pin to decouple LNA in TX mode
Input to switch on the system (active high)
Key input 5 (can also be used to switch on the system (active low))
Key input 4 (can also be used to switch on the system (active low))
Key input 3 (can also be used to switch on the system (active low))
Key input 2 (can also be used to switch on the system (active low))
Key input 1 (can also be used to switch on the system (active low))
Indicates RX operation mode
Not connected
Not connected
Ground/backplane
Atmel ATA5428 [DATASHEET]
4841E–WIRE–03/12
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