ATA5811_06 ATMEL [ATMEL Corporation], ATA5811_06 Datasheet - Page 2

• Manufacturer Part Number: ATA5811_06
• Description: UHF ASK/FSK TRANSCEIVER
• Manufacturer: ATMEL [ATMEL Corporation]

Applications
Benefits
1. General Description
2
ATA5811/ATA5812
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The ATA5811/ATA5812 is a highly integrated UHF ASK/FSK single-channel half-duplex trans-
ceiver 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 synthe-
sizer is used for FSK transmission and switching of the power amplifier for ASK transmission.
The device supports data rates of 1 Kbit/s to 20 Kbit/s (FSK) and 1 Kbit/s to 10 Kbit/s (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 ATA5812 in the 314 MHz to
316 MHz band. The very high system integration level results in few numbers of external compo-
nents 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 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.
Its 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 func-
tions 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 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 communications with arbitration of the communication part-
ner have to be handled.
It is hence possible to design bi-directional RKE and access control systems with a fast chal-
lenge response crypto function with the same PCB board size and with the same current
consumption as uni-directional RKE systems.
Automotive Keyless Entry and Passive Entry Go Systems
Access Control Systems
Remote Control Systems
Alarm and Telemetry Systems
Energy Metering
Home Automation
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, 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 Key Fob to Surround the Whole Application
4689F–RKE–08/06