Features
Multi Channel Halfduplex Transceiver with Approximately 2.5 MHz Programmable
Tuning Range
High FSK Sensitivity: 106 dBm at 20 kBaud/109.5 dBm at 2.4 kBaud (433.92 MHz)
High ASK Sensitivity: 112.5 dBm at 10 kBaud/116.5 dBm at 2.4 kBaud (433.92 MHz)
Low Supply Current: 10.5 mA in RX and TX Mode (3 V/TX with 5 dBm)
Data Rate: 1 to 20 kBaud Manchester FSK, 1 to 10 kBaud Manchester ASK
ASK/FSK Receiver Uses a LowIF Architecture with High Selectivity, Blocking, and
Low Intermodulation (Typical Blocking 55 dB at 750 kHz/61 dB at 1.5 MHz and
70 dB at 10 MHz, System I1dBCP = 30 dBm/System IIP3 = 20 dBm)
226 kHz IF Frequency with 30 dB Image Rejection and 170 kHz Usable IF Bandwidth
(TBD)
Transmitter Uses Closed Loop FractionalN Synthesizer for FSK Modulation with a
High PLL Bandwidth and an Excellent Isolation between PLL/VCO and PA
Tolerances of XTAL Compensated by FractionalN Synthesizer with 800 Hz RF
Resolution
Integrated RX/TXSwitch, Singleended RF Input and Output
RSSI (Received Signal Strength Indicator)
Communication to Microcontroller with SPI Interface Working at Maximum 500 kBit/s
Configurable Self Polling and RX/TX Protocol Handling with FIFORAM Buffering of
Received and Transmitted Data
5 Push Button Inputs and One Wakeup Input are Active in Powerdown Mode
Integrated XTAL Capacitors
PA Efficiency: up to 38% (433.92 MHz/10 dBm/3 V)
Low Inband Sensitivity Change of Typically 1.8 dB within 58 kHz Center Frequency
Change in the Complete Temperature and Supply Voltage Range (TBD)
Supply Voltage Switch, Supply Voltage Regulator, Reset Generation, Clock/Interrupt
Generation and Low Battery Indicator for Microcontroller
Fully Integrated PLL with Low Phase Noise VCO, PLL Loop Filter and Full Support of
Multichannel Operation with Arbitrary Channel Distance Due to FractionalN
Synthesizer
Sophisticated Threshold Control and Quasipeak Detector Circuit in the Data Slicer
Power Management via Different Operation Modes
315 MHz, 345 MHz, 433.92 MHz, 868.3 MHz and 915 MHz without External VCO and PLL
Components
Inductive Supply with Voltage Regulator if Battery is Empty (AUX Mode)
Efficient XTO Startup Circuit (> 1.5 k
Worst Case Real Startup 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 10 dBm Adjusted and Stabilized with External Resistor
ESD Protection at all Pins (2 kV HBM, 200 V MM, TBD FCDM)
Supply Voltage Range: 2.4 V to 3.6 V or 4.4 V to 6.6 V
Temperature Range: 40C to +85C
Small 7
7 mm QFN48 Package
UHF ASK/FSK
Transceiver
ATA5423
ATA5425
ATA5428
ATA5429
Preliminary
Rev. 4841ARKE02/05
2
4841ARKE02/05
ATA5423/25/28/29 [Preliminary]
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 Powerdown Mode,
Delivering of Clock, Reset, Low Battery Indication and Complete Handling of Receive/Transmit
Protocol and Polling
Singleended 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
3
4841ARKE02/05
ATA5423/25/28/29 [Preliminary]
1.
General Description
The ATA5423/25/28/29 is a highly integrated UHF ASK/FSK multichannel halfduplex trans-
ceiver with low power consumption supplied in a small 7 x 7 mm QFN48 package. The receive
part is built as a fully integrated lowIF receiver, whereas direct PLL modulation with the frac-
tionalN synthesizer is used for FSK transmission and switching of the power amplifier for ASK
transmission.
The device supports data rates of 1 kBaud to 20 kBaud (FSK) and 1 kBaud to 10 kBaud (ASK)
in Manchester, Biphase and other codes in transparent mode. The ATA5428 can be used in
the 431.5 MHz to 436.5 MHz and in the 862 MHz to 872 MHz bands, the ATA5423 in the
312.5 MHz to 317.5 MHz band, the ATA5425 in the 342.5 MHz to 347.5 MHz band and the
ATA5429 in the 912.5 MHz to 917.5 MHz band. 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 15 dB to 20 dB 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 typi-
cal remote control and access control system on both sides (the base and the mobile stations)
are fully integrated.
Its digital control logic with selfpolling and protocol generation enables a fast challenge
response system without using a highperformance microcontroller. Therefore, the
ATA5423/ATA5425/ATA5428/ATA5429 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 4/8bit microcontroller without special
periphery and clocked with the CLK output of about 4.5 MHz is sufficient to control the communi-
cation link. This is especially valid for passive entry and access control systems, where within
less than 100 ms several challengeresponse communications with arbitration of the communi-
cation partner have to be handled.
It is hence possible to design bidirectional remote control and access control systems with a
fast challengeresponse crypto function, with the same PCB board size and with the same cur-
rent consumption as unidirectional remote control systems.
Figure 1-1.
System Block Diagram
RF Transceiver
Digital Control
Logic
C_Interface
Power
Supply
XTO
C
Antenna
4 ... 8
Matching/
RF Switch
ATA5423/25/28/29
4
4841ARKE02/05
ATA5423/25/28/29 [Preliminary]
Figure 1-2.
Pinning QFN48
Table 1-1.
Pin Description
Pin
Symbol
Function
1
NC
Not connected
2
NC
Not connected
3
NC
Not connected
4
RF_IN
RF input
5
NC
Not connected
6
433_N868
Selects RF input/output frequency range
7
NC
Not connected
8
R_PWR
Resistor to adjust output power
9
PWR_H
Pin to select output power
10
RF_OUT
RF output
11
NC
Not connected
12
NC
Not connected
13
NC
Not connected
14
NC
Not connected
15
NC
Not connected
16
AVCC
Blocking of the analog voltage supply
17
VS2
Power supply input for voltage range 4.4 V to 6.6 V
18
VS1
Power supply input for voltage range 2.4 V to 3.6 V
19
VAUX
Auxiliary supply voltage input
20
TEST1
Test input, at GND during operation
21
DVCC
Blocking of the digital voltage supply
NC
NC
NC
RF_IN
NC
433_N868
NC
R_PWR
PWR_H
RF_OUT
NC
NC
RSSI
CS
DEM_OUT
SCK
SDI_TMDI
SDO_TMDO
CLK
IRQ
N_RESET
VSINT
NC
XTAL2
NC
NC
RX
_A
C
T
I
V
E
T1
T2
T3
T4
T5
PW
R
_
O
N
RX
_T
X1
RX
_T
X2
CDE
M
NC
NC
NC
AVC
C
VS2
VS1
VAU
X
TEST1
DV
CC
VSO
U
T
TEST2
XTAL
1
48 47 46 45 44 43 42 41 40 39 38 37
13 14 15 16 17 18 19 20 21 22 23 24
1
2
3
4
5
6
7
8
9
10
11
12
36
35
34
33
32
31
30
29
28
27
26
25
ATA5423/ATA5425
ATA5428/ATA5429
5
4841ARKE02/05
ATA5423/25/28/29 [Preliminary]
22
VSOUT
Output voltage power supply for external devices
23
TEST2
Test input, at GND during operation
24
XTAL1
Reference crystal
25
XTAL2
Reference crystal
26
NC
Not connected
27
VSINT
Microcontroller interface supply voltage
28
N_RESET
Output pin to reset a connected microcontroller
29
IRQ
Interrupt request
30
CLK
Clock output to connect a microcontroller
31
SDO_TMDO
Serial data out/transparent mode data out
32
SDI_TMDI
Serial data in/transparent mode data in
33
SCK
Serial clock
34
DEM_OUT
Demodulator open drain output signal
35
CS
Chip select for serial interface
36
RSSI
Output of the RSSI amplifier
37
CDEM
Capacitor to adjust the lower cut
off frequency data filter
38
RX_TX2
GND pin to decouple LNA in TX mode
39
RX_TX1
Switch pin to decouple LNA in TX mode
40
PWR_ON
Input to switch on the system (active high)
41
T5
Key input 5 (can also be used to switch on the system (active low))
42
T4
Key input 4 (can also be used to switch on the system (active low))
43
T3
Key input 3 (can also be used to switch on the system (active low))
44
T2
Key input 2 (can also be used to switch on the system (active low))
45
T1
Key input 1 (can also be used to switch on the system (active low))
46
RX_ACTIVE
Indicates RX operation mode
47
NC
Not connected
48
NC
Not connected
GND
Ground/backplane
Table 1-1.
Pin Description (Continued)
Pin
Symbol
Function
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