ATA5279P-PLQW Atmel, ATA5279P-PLQW Datasheet - Page 28

• Manufacturer Part Number: ATA5279P-PLQW
• Description: IC ANTENNA DVR SIX-FOLD 48QFN
• Manufacturer: Atmel

Specifications of ATA5279P-PLQW

• Rf Type: PEG, TPMS
• Frequency: 125kHz
• Features: RSSI Equipped
• Package / Case: 48-VQFN Exposed Pad, 48-HVQFN, 48-SQFN, 48-DHVQFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

4.1
28
Application Hints
Atmel ATA5279
Table 4-1.
An important application aspect is the thermal budget. Under certain conditions, high power
dissipations can occur during operation of the chip. The Atmel
mainly depends on the supply voltage and the selected antenna output current. Under worst
case conditions (e.g., low supply voltage and maximum antenna power) the power dissipation
increases exponentially and may rise to values exceeding 10W. It must be avoided under all
circumstances to exceed the specified maximum average junction temperature. Therefore, the
thermal aspects of the entire application, along with the electrical design, are essential.
The thermal resistance between the IC and the ambient has to be designed according to the
specific application requirements. It is mandatory to solder the exposed die pad to the PCB.
As many vias as possible must be provided between the top and the bottom layer (soldering
side to the PCB's backside). This copper plane is able to store and dissipate the heat. It must
be electrically connected to ground, and an appropriate heat transfer away from the chip must
be ensured. In addition, multi-layer-PCBs (more than two layers) are recommended.
The ATA5279's power dissipation depends on the supply voltage, the selected antenna
current, the antenna's impedance and further parameters such as the external components
used for the DC-DC converter. Background information, design hints and an example are
given in the application note “LF Antenna Driver ATA5279 – Thermal Considerations and PCB
Design Hints”.
It is strongly recommended to measure the power dissipation in the target application during
the design phase to verify the system's thermal budget. One option is to calculate the differ-
ence between input and output power.
Part
R1
C1
C2
C3
C4
C5
C6
C7
D1
D2
X1
L1
L2
Bill of Materials (BOM) for Typical Application Circuit
4.7µF/50V tant.
50V/3A/50ns
220µF/50V
100nF cer.
100nF cer.
100nF cer.
100nF cer.
33nF cer.
50V/3A
150µH
8MHz
Value
82µH
1
Description
Shunt resistor, ±1% tolerance
Supply line input filter and stabilizing cap
Supply line input filter cap
Boost converter storage cap, low ESR
Boost converter filter cap (+ESD clamp)
Internal 5V supply line stabilizing cap
Integration cap for current regulation loop
Filter cap for µC supply line
Rectifying diode
High-speed freewheeling diode
Supply line input filter choke, I
Boost converter charging choke, I
Crystal or resonator
®
ATA5279's power dissipation
sat
> 3A
sat
> 3A
9125L–RKE–03/11