ATA5283P-6AP ATMEL [ATMEL Corporation], ATA5283P-6AP Datasheet - Page 3

• Manufacturer Part Number: ATA5283P-6AP
• Description: Interface IC for 125 kHz Wake-up Function
• Manufacturer: ATMEL [ATMEL Corporation]

Functional
Description
AGC Amplifier
Preamble Detection
Figure 3. Communication Protocol
4598D–AUTO–03/04
Procedure
Signal
N_DATA
N_WAKEUP
RESET
Gain
control
Current
profile
192 Periods
No gain
1 µA
control
of LF
Preamble
>5.64 ms
>512 Periods
adjustment
AGC
of LF
The ATA5283 is an ultra-low power ASK receiver. Without a carrier signal it operates in
the standby listen mode. In this mode it monitors the coil input with a very low current
consumption. To activate the IC and the connected control unit, the transmitting stage
must send the preamble carrier burst. After a preamble is detected the IC is activated. It
adapts the gain of the input stage and enables the wake-up and the data output. The
first gap at the end of the preamble generates a wake-up signal for the microcontroller.
After that the receiver outputs the data signal at N_DATA. To return the IC into the
standby listen mode it must be reset via the RESET input.
The input stage contains an Automatic Gain Control (AGC) amplifier to amplify the input
signal from the coil. The gain is adjusted by the automatic gain control circuit if a pream-
ble signal is detected. The high dynamic range of the AGC enables the IC to operate
with input signals from 1 mV
put delivers a 125 kHz signal with an amplitude adjusted for the following evaluation
circuits’ preamble detection, signal conditioner, wake-up.
Before data transmission the IC stays in standby listen mode. To prevent the circuit from
unintended operations in a noisy environment the preamble detection circuit checks the
input signal. A valid signal is detected by a counter after 192 carrier periods without
interrupts. Short interrupts which are suppressed by the signal conditioner are tolerated.
When a valid carrier (preamble) is found the circuit starts the automatic gain control. It
requires up to 512 carrier periods to settling. The complete preamble should have 704
carrier periods minimum. The preamble is terminated and the data transfer is started
with the first gap (Start Gap) in the carrier (see Figure 3).
Start
gap
Gain control
2 µA
active
rms
to 1.1 V
rms
Data
ATA5283 [Preliminary]
. After the AGC settling time the amplifier out-
No Gain Control
0.5 µA
3