ATA5812

Features:

•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 Low-IF 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
•Transmitter Uses Closed Loop Fractional-N Synthesizer for FSK Modulation with a High PLL Bandwidth and an Excellent Isolation between PLL and PA
•Tolerances of XTAL Compensated by Fractional-N Synthesizer with 800 Hz 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 Maximum 500 kBit/s
•Configurable Self Polling and RX/TX Protocol Handling with FIFO-RAM Buffering of Received and Transmitted Data
•5 Push Button Inputs and One Wake-up Input are Active in Power-down Mode
•Integrated XTAL Capacitors
•PA Efficiency: up to 38% (433 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
•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 and PLL Loop Filter
•Sophisticated Threshold Control and Quasi Peak Detector Circuit in the Data Slicer
•Power Management via Different Operation Modes
•433.92 MHz, 868.3 MHz and 315 MHz without External VCO and PLL Components
•Inductive Supply with Voltage Regulator if Battery is Empty (AUX Mode)
•Efficient XTO Start-up Circuit (> -1.5 kΩ Worst Case Start 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)
•Supply Voltage Range: 2.4 V to 3.6 V or 4.4 V to 6.6 V
•Temperature Range: -40°C to +105°C
•Small 7 × 7 mm QFN48 Package


Application

•Automotive Keyless Entry and Passive Entry Go Systems
•Access Control Systems
•Remote Control Systems
•Alarm and Telemetry Systems
•Energy Metering
•Home Automation


Pinout




Specifications

Parameters	Symbol	Min.	Max.	Unit
Junction temperature	Tj		150
Storage temperature	Tstg	-55	+125
Ambient temperature	Tamb	-40	+105
Supply voltage VS2	VMaxVS2	-0.3	+7.2	V
Supply voltage VS1	VMaxVS1	-0.3	+4	V
Supply voltage VAUX	VMaxVAUX	-0.3	+7.2	V
Supply voltage VSINT	VMaxVSINT	-0.3	+5.5	V
ESD (Human Body Model ESD S 5.1) every pin	HBM	-2	+2	kV
ESD (Machine Model JEDEC A115A) every pin	MM	-200	+200	V
Maximum input level, input matched to 50 Ω	Pin_max		10	dBm

Description

The ATA5811/ATA5812 is a highly integrated UHF ASK/FSK single-channel half-duplex transceiver with low power consumption supplied in a small 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 1 kBaud to 20 kBaud (FSK) and 1 kBaud to 10 kBaud (ASK) in Manchester, Bi-phase and other codes in transparent mode. The ATA5811 can be used in the 433 MHz to 435 MHz and the 868 MHz to 870 MHz band, the ATA5812in the 314 MHz to 316 MHz band. The very high system integration level results in few numbers of external components needed.

Due to ATA5812's blocking and selectivity performance, together with the additional 15 dB to 20 dB loss and the narrow bandwidth of a typical key fob loop antenna, a bulky blocking SAW is not needed in the key fob or sensor 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.

ATA5812's digital control logic with self polling and protocol generation enables a fast challenge response systems without using a high-performance microcontroller. Therefore, the ATA5811/ATA5812 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 mes-sages and controlling other devices. Due to that, a standard 4-/8-bit microcontroller without special periphery and clocked with the CLK output of about 4.5 MHz is sufficient to control the communication link. This is especially valid for passive entry and access control systems, where within less than 100 ms several challenge response communi-cations with arbitration of the communication partner have to be handled.

ATA5812 is hence possible to design bi-directional RKE 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 RKE systems.