ATA5823/ATA5824
UHF ASK/FSK Transceiver
DATASHEET
Features
●
High FSK sensitivity: –105.5dBm at 20Kbit/s/–109dBm at 2.4Kbit/s (433.92MHz)
●
High ASK sensitivity: –111.5dBm at 10Kbit/s/–116dBm at 2.4Kbit/s (100% ASK,
carrier level 433.92MHz)
●
Low supply current: 10.5mA in RX and TX mode (3V/TX with 5dBm/433.92MHz)
●
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 3dB blocking 55.5dBC at ±750kHz/60.5dBC at ±1.5MHz
and 67dBC at ±10MHz, system I1dBCP = –30dBm/system IIP3 = –20dBm)
●
Wide bandwidth AGC to handle large outband blockers above the system I1dBCP
●
226kHz IF (intermediate frequency) with 30dB image rejection and 220kHz system
bandwidth to support TPM transmitters using Atmel
®
ATA5756/ATA5757
transmitters with standard crystals
●
Transmitter uses closed loop FSK modulation with fractional-N synthesizer with
high PLL bandwidth and an excellent isolation between PLL 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 500kBit/s
maximum
●
Configurable self polling and RX/TX protocol handling with FIFO-RAM buffering of
received and transmitted data
●
1 push button input and 1 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 ±2.0dB within ±75kHz center frequency
change in the complete temperature and supply voltage range
4829F-RKE-05/14
●
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
●
433.92MHz, and 315MHz without external VCO and PLL components
●
Efficient XTO start-up circuit (> –1.5kΩ worst case start impedance)
●
Changing of modulation type ASK/FSK and data rate without component changes to allow different modulation schemes in
TPM and RKE
●
Minimal external circuitry requirements for complete system solution
●
Adjustable output power: 0 to 10dBm adjusted and stabilized with external resistor, programmable output power with 0.5dB
steps with internal resistor
●
Clock and interrupt generation for microcontroller
●
ESD protection at all pins (±2.5kV HBM, ±200V MM, ±500V FCDM)
●
Supply voltage range: 2.15V to 3.6V or 4.4V to 5.25V
●
Typical power-down current < 10nA
●
Temperature range: –40°C to +105°C
●
Small 7mm
×
7mm QFN48 package
Applications
●
Automotive keyless entry and passive entry go (handsfree car access)
●
Tire pressure monitoring systems
●
Remote control systems
●
Alarm and telemetering systems
●
Energy metering
●
Home automation
Benefits
●
No SAW device needed in key fob designs to meet automotive specifications
●
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 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 key fob to
surround the whole application
●
Integration of tire pressure monitoring, passive entry and remote keyless entry
2
ATA5823/ATA5824 [DATASHEET]
4829F–RKE–05/14
1.
General Description
The Atmel
®
ATA5823/ATA5824 is a highly integrated UHF ASK/FSK multi-channel half-duplex transceiver with low power
consumption supplied in a small 7mm
×
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 Atmel ATA5824 can be used in the 433MHz to 435MHz band and the Atmel ATA5823 in the
313MHz to 316MHz band. The very high system integration level results in few numbers of external components needed.
Due to its blocking and selectivity performance, together with a typical narrow-band key-fob loop antenna with 15dB to 20dB
loss, a bulky blocking SAW is not needed in the key fob application. Additionally, the building blocks needed for a typical
RKE 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 provides a fast challenge response system without using a
high-performance microcontroller. Therefore, the Atmel ATA5823/ATA5824 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. Due to that, a standard
4-/8-bit microcontroller without special periphery and clocked with the delivered CLK output of about 4.5MHz is sufficient to
control the communication link. This is especially valid for passive entry go and access control systems, where within less
than 100 ms several communication responses with arbitration of the communication partner have to be handled. It is hence
possible to design bi-directional RKE and passive entry go systems with a fast challenge response crypto function and
prevention against relay attacks.
Figure 1-1. System Block Diagram
ATA5823/ATA5824
RF Transceiver
Antenna
Digital Control
Logic
Power
Supply
Micro-
controller
Matching/
RF Switch
Microcontroller
interface
4 to 8
XTO
ATA5823/ATA5824 [DATASHEET]
4829F–RKE–05/14
3
2.
Pin Configuration
Figure 2-1. Pinning QFN48
RX_ACTIVE
N_PWR_ON
SCK_PHA
SCK_POL
NC
PWR_ON
RX_TX1
RX_TX2
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
31
30
29
28
27
26
NC
NC
NC
1
2
3
4
5
6
7
8
9
10
11
RSSI
CS
TEST3
SCK
SDI_TMDI
SDO_TMDO
CLK
IRQ
POUT
VSINT
NC
XTAL2
ATA5823/ATA5824
12
25
13 14 15 16 17 18 19 20 21 22 23 24
VS1
SETPWR
DVCC
CS_POL
TEST2
NC
AVCC
VS2
Table 2-1.
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
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
SETPWR
TEST1
DVCC
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 5.6V
Power supply input for voltage range 2.15V to 3.6V
Internal Programmable Resistor to adjust output power
Test input, at GND during operation
Blocking of the digital voltage supply
4
ATA5823/ATA5824 [DATASHEET]
4829F–RKE–05/14
TEST1
TXAL1
NC
NC
Table 2-1.
Pin
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
CS_POL
TEST2
XTAL1
XTAL2
NC
VSINT
POUT
IRQ
CLK
SDO_TMDO
SDI_TMDI
SCK
TEST3
CS
RSSI
CDEM
RX_TX2
RX_TX1
PWR_ON
NC
NC
SCK_POL
SCK_PHA
N_PWR_ON
RX_ACTIVE
NC
NC
GND
Function
Select polarity of pin CS
Test input, at GND during operation
Reference crystal
Reference crystal
Not connected
Microcontroller interface supply voltage
Programmable output
Interrupt request
Clock output to connect a microcontroller
Serial data out/transparent mode data out
Serial data in/transparent mode data in
Serial clock
Test output open during operation
Chip select for serial interface
Output of the RSSI amplifier
Capacitor to adjust the lower cut-off frequency data filter
Has to be connected GND
Switch pin to decouple LNA in TX mode (RKE mode)
Input to switch on the system (active high)
Not connected
Not connected
Polarity of the serial clock
Phase of the serial clock
Keyboard input (can also be used to switch on the system, active low)
Indicates RX operation mode
Not connected
Not connected
Ground/Backplane (exposed die pad)
ATA5823/ATA5824 [DATASHEET]
4829F–RKE–05/14
5
