ata5428 ATMEL Corporation, ata5428 Datasheet - Page 3

• Manufacturer Part Number: ata5428
• Description: Uhf Ask/fsk Transceiver
• Manufacturer: ATMEL Corporation

1. General Description
4841D–WIRE–10/07
The ATA5423/25/28/29 is a highly integrated UHF ASK/FSK multi-channel half-duplex 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 low-IF receiver, whereas direct PLL modulation with the frac-
tional-N synthesizer 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 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 self-polling and protocol generation enables a fast challenge-
response system without using a high-performance 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-/8-bit 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 challenge-response communications with arbitration of the communi-
cation 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 cur-
rent consumption as uni-directional remote control systems.
ATA5423/ATA5425/ATA5428/ATA5429
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