Features
Antenna Driver Stage with Adjustable Antenna Peak Current for up to 1.5 A
Frequency Tuning Range from 100 kHz to 150 kHz
Automatic Antenna Peak Current Regulation
Self-tuning Oscillator for Antenna Resonant Frequency Adaption
Capable of Driving a High-Q Antenna
Integrated 5 V Regulator for External Load up to 10 mA
Bi-directional Single Wire Interface for Microcontroller or ECU
LF Baud Rates up to 4 kbaud and Amplitude Shift Keying (ASK) Modulation
Low Power Standby Mode < 50 A
Antenna Driver Diagnosis: Peak Current, Antenna Frequency and Battery Voltage
Monitoring
Power Supply Range 8 V to 24 V Direct Battery Input
Load Dump Protection up to 45 V for 12 V Boards
Operation at Temperature -40C to +105C
EMI and ESD According to Automotive Requirements
Highly Integrated, Fewer External Components Required
Driver Overcurrent Protection
Overtemperature Protection
Applications
Tire Pressure Measurement (TPM)
Benefits
Self Tuning Capability to Antenna Resonance Frequency
Adjustable Antenna Peak Current Value
Highest Integration Level for Embedded Automotive Systems
Electrostatic sensitive device.
Observe precautions for handling.
Description
The ATA5275 is an integrated 1.5 A peak current BCDMOS antenna driver IC dedi-
cated as a 125 kHz wake-up channel transmitter for TPM applications.
It includes the full functionality to generate a magnetic LF field in conjunction with an
antenna coil to transmit data and power to a receiver. The transmission can be con-
trolled via a one wire I/O-interface by an external unit.
The smart power IC is delivered in a QFN20 power package with heat slug.
125 kHz
Transmitter IC
for TPM
ATA5275
Preliminary
Rev. 4739CAUTO02/05
2
4739CAUTO02/05
ATA5275 [Preliminary]
1.
General Description
The ATA5275 is a 125-kHz transmitter IC. It is dedicated to driving 125 kHz LC antenna tanks,
specifically for the wake-up channel in Tire Pressure Measurement (TPM) applications.
It includes a control logic with VCO which generates the 125 kHz signal for the output driver
stage. A phase lock circuit regulates the driver output frequency on the antenna resonance fre-
quency, achieving a maximum field strength on the antenna. The driver duty cycle is regulated
and stabilizes the antenna current for a wide supply voltage range.
The IC can be controlled by a microcontroller or ECU via the one wire bi-directional interface. It
is used for the data transmission and to indicate errors. For the data transmission ASK modula-
tion is used. The antenna signal is modulated by the DIO interface line.
The IC has a build in diagnosis function and detects detuning and broken or short wire of the
antenna circuitry. If a failure is detected the IC indicates it by an error signal via the DIO line.
The integrated 5 V regulator can be used externally for a load up to 10 mA.
Figure 1-1.
Block Diagram
ATA5275
125-kHz Transmitter
5 V
REG
K-
Line
REF
Gate
Dr
iv
e
C
ontr
o
l
St
a
t
e
Mach
in
e
19
BOOST
14
TM2
15
TM1
13
TM3
9
SENSE
6
DVSS3
8
DVSS1
7
DVSS2
3
DRV3
4
DRV2
2
DVCC1
1
DVCC2
10
VSS
5
DRV1
Ha
lf
Br
id
g
e
12
RCR
11
REXT
17
DIO
16
VDIO
18
VCC
20
DVCC3
BIAS
VCO
XO
R
3
4739CAUTO02/05
ATA5275 [Preliminary]
2.
Pin Configuration
Figure 2-1.
Pinning QFN20
ATA5275
19
BOOST
14
TM2
15
TM1
13
TM3
9
SENSE
6
DVSS3
8
DVSS1
7
DVSS2
3
DRV3
4
DRV2
2
DVCC1
1
DVCC2
10
VSS
5
DRV1
12
RCR
11
REXT
17
DIO
16
VDIO
18
VCC
20
DVCC3
Table 2-1.
Pin Description
Pin
(1)
Symbol
Function
1
DVCC2
Battery supply input
2
DVCC1
Battery supply input
3
DRV3
Antenna driver stage output
4
DRV2
Antenna driver stage output
5
DRV1
Antenna driver stage output
6
DVSS3
Power supply ground
7
DVSS2
Power supply ground
8
DVSS1
Power supply ground
9
SENSE
Current zero crossing sense input
10
VSS
Analog and digital ground
11
REXT
External reference current input
12
RCR
External reference for antenna peak current
13
TM3
For test purposes only
14
TM2
For test purposes only
15
TM1
For test purposes only
16
VDIO
DIO line interface voltage selection
17
DIO
One-wire serial interface line
18
VCC
5 V supply output (for external storage capacitor only)
19
BOOST
External bootstrap cap
20
DVCC3
Battery supply input
Note:
1. Pin numbers valid for all revisions of the ATA5275
4
4739CAUTO02/05
ATA5275 [Preliminary]
3.
Functional Description
3.1
Operation Modes
There are two different operation modes for the ATA5275:
Standby mode
Transmission mode
3.2
Standby Mode and Wake-up
After power-on-reset, the ATA5275 is in standby mode. For minimum power consumption, only
the internal 5 V supply and the DIO line interface are active. The IC can be activated by the
external control unit via the serial interface. The DIO line is called logic high if it is pulled up to
the VDIO voltage level. The DIO line is called logic low if it is pulled down to the VSS voltage
level. A low signal at the DIO line wakes-up the IC.
The circuit enters the standby mode if either of these three conditions are fulfilled:
1.
After power-on-reset and the DIO is high (see
Figure 3-1
)
2.
After a time out of T
OUTL
(1)
during which DIO is permanently low (see
Figure 3-3 on
page 5
)
3.
After a time out of T
OUTH
(2)
during which DIO is permanently high and an acknowledge
time T
ACK
/T
ERR
(1)
(see
Figure 3-2
)
Notes:
1. Time does not depend on the antenna resonance frequency.
2. Time depends on the antenna resonance frequency.
Figure 3-1.
STBY After POR
Figure 3-2.
STBY After DIO = H
t
t
STBY
DIO
POR
t
t
t
STBY
TOUT_H
TACK/TERR
DIO
5
4739CAUTO02/05
ATA5275 [Preliminary]
Figure 3-3.
STBY After DIO = L
3.3
Transmission Mode
3.3.1
ASK Modulation
For the transmission of a wake-up signal or data to a receiver, the ATA5275 generates a
antenna resonance synchronized signal at the antenna driver output (DRV pin). A connected LC
antenna radiates a magnetic field. For the data transmission the field can be 100% amplitude
modulated by the DIO interface input. If a low level signal is applied at the DIO pin, the driver
generates a square wave signal DRV for the antenna. If a high level signal is applied at the DIO
pin the driver is stopped and switched to ground. In this way ASK modulated data can be trans-
mitted (see
Figure 3-4
).
Figure 3-4.
Data Transmission
3.3.2
Anti-bouncing Filter in Transmission Mode
The DIO input signal is delayed for a anti-bouncing time.
The driver is switched on after a delay time of T
DL
(typically 64 s) if the DIO is pulled to a low
level continuously. The driver is switched-off after a delay time of T
DH
if the DIO is pulled to high
level.
The T
DH
time depends on the antenna resonance frequency, suppressing short disturbance
pulses from the DIO Line.
Figure 3-5.
Anti-bouncing
t
t
STBY
TOUT_L
DIO
DIO
DRV
COIL
TD_L
TD_H
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