3

4694E–AUTO–08/05

ATA5282

3.

Functional Description

The ATA5282 is a 3-channel ASK receiver for 125-kHz carrier signals. Its three active input

stages with very low power consumption and high input sensitivity allow to connect up to 3

antennas for direction-independent wake-up function and data transfer.

Without a carrier signal the ATA5282 operates in standby listen mode. In this mode, it moni-

tors the 3 Coil inputs with a very low current consumption. To activate the IC and the

connected control unit, the transmitting end must send a preamble carrier burst and the

header code. When a preamble has been detected, the IC activates the internal oscillator and

the header check. The last gap at the end of a valid header enables the NDATA output.

During data transfer, the NDATA pin outputs the demodulated and merged signal of the 3

input stages.

To achieve data rates up to 4 kbps for input signals from 2.8 mV

control the gain of the amplifiers. Each of the 3 input stages contain an amplifier with Auto-

matic Gain Control (AGC). It is used to adapt the gain to the incoming signal strength, and is

also used as RSSI for field strength measurements.

The integrated synchronous serial interface uses the NSCL together with the NDATA pin as

clock and data line. It allows to control several functions as well as read out the received signal

field strength. Enabling only single coil inputs, freezing the actual status of the automatic gain

control or resetting the complete circuit to the initial state at any time are built-in features.

When communication is finished or a time out event occurs, the internal watchdog timer or

reset command via the serial interface sets the IC to standby listen mode.