File ata5283

7
ATA5283 [Preliminary]
4598D–AUTO–03/04
Reset The IC is reset either by the internal POR circuit during a power on sequence or by a
high pulse at the RESET pin. After the reset all internal counters are in the initial state
and the IC is in the standby listen mode.
The POR circuit generates a reset while the supply voltage V
DD
is below the power on
reset threshold V
POR
and release the function of the IC if V
DD
exceeds this threshold.
A high signal at the RESET pin resets the complete circuit. If the IC is activated a reset
signal is necessary to activate the standby listen mode.
The RESET pin can also be used to hold the IC in a power down state. In this state the
the IC is out of operation and the current consumption is below the standby current.
Note: The RESET pin is high impedance CMOS input. To avoid floating effects like undefined
input states and malfunctions it should not be open.
Standby Listen Mode In the standby listen mode the IC monitors the coil input with a very low current con-
sumption. The automatic gain control is switched off and the gain is set to the maximum
value. The N_DATA and the N_WAKEUP output are set to a high level.
Before the controller enters its standby mode after the communication, it should activate
the standby listen mode of the ATA5283 with a reset signal. This measure ensures that
the IC enters the power saving standby mode and that the IC wakes the controller cor-
rectly with the next preamble signal.
Applications Figure 8 shows a typical TPM application of the ATA5283. Combined with the antenna
resonant circuit the ATA5283 is used as wake-up receiver for the microcontroller and
the connected temperature- and pressure-sensor.
Note: To avoid supply voltage ripples to affect the microcontroller, an RC filter (R1 = 100 Ω,
C1 = 10 nF) is recommended.
Figure 8. Application
Central
Board
Controller
Antenna
Driver
Micro
controller
N_DATA
N_WAKEUP
ATA5275
UHF - Rx
T5743
UHF - Tx
125 kHz
433 MHz
Temp.
Sensor
Pressure
Sensor
Amplifier
with
AGC
Vref
ATA5283
∫
LA CA
RESET
R1
C1
1
2
3
4
6
7
5
8
ATAR862