ATA6286N-PNQW Atmel, ATA6286N-PNQW Datasheet - Page 16

• Manufacturer Part Number: ATA6286N-PNQW
• Description: IC CTRL/XMITTER 433MHZ 32-VQFN
• Manufacturer: Atmel

Specifications of ATA6286N-PNQW

• Frequency: 433MHz
• Applications: TPM (Tire Pressure Monitor)
• Modulation Or Protocol: ASK, FSK
• Data Rate - Maximum: 20 kbps
• Power - Output: 6dBm
• Current - Transmitting: 8.5mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 2 V ~ 3.6 V
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
• Processor Series: ATA6x
• Core: AVR8
• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 128 KB
• Data Ram Size: 512 B
• Interface Type: SPI
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 85
• Number Of Timers: 9
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Memory Size: -
• Lead Free Status / Rohs Status: Details

4.5.5.1
4.5.6
16
ATA6285N/ATA6286N [Preliminary]
Output Matching and Power Setting
Clock Pulse Take-over by Microcontroller
The clock of the crystal oscillator can be used for clocking the microcontroller. Atmel’s ATARx9x
microcontroller family provides the special feature of starting with an integrated RC oscillator to
switch on the ATA6285N/ATA6286N external clocking and to wait automatically until the CLK
output of the ATA6285N/ATA6286N is activated. After a time period of 250 µs the message can
be sent with crystal accuracy.
The output power is set by the load impedance of the antenna. The maximum output power is
achieved with a load impedance of Z
Z
deliver the DC current.
The power amplifier delivers a current pulse and the maximum output power is delivered to a
resistive load if the 0.66 pF output capacitance of the power amplifier is compensated by the
load impedance.
At the ANT1 pin, the RF output amplitude is about V
The load impedance is defined as the impedance seen from the ATA6285N’s ANT1, ANT2 into
the matching network. Do not mix up this large-signal load impedance with a small-signal input
impedance delivered as an input characteristic of RF amplifiers.
The latter is measured from the application into the IC instead of from the IC into the application
for a power amplifier.
The 0.66 pF output capacitance absorbed into the load impedance a real impedance of 684
(ATA6285N) at 315 MHz and 623 (ATA6286N) at 433.92 MHz should be measured with a net-
work analyses at pin 5 (ANT1) with the ATA6285N/ATA6286N soldered, an optimized antenna
connected and the power amplifier switched off.
Less output power is achieved by lowering the real parallel part where the parallel imaginary part
should be kept constant. Lowering the real part of the load impedance also reduces the supply
voltage dependency of the output power.
Output power measurement can be done with the circuit as shown in Output Power Measure-
ment. Please note that the component values must be changed to compensate the individual
board parasitics until the ATA6285N/ATA6286N has the right load impedance. Also, the damp-
ing of the cable used to measure the output power must be calibrated.
Figure 4-7.
Load, opt
= 280 + j310 (ATA6285N) at 433.92 MHz. A low resistive path to V
Output Power Measurement ATA6285N/ATA6286N
ANT1
ANT2
Z
Lopt
V
C
C
L
S
1
2
1
= 1 nF
= 2.2 pF/ 1.8 pF
= 68 nH/ 39 nH
Load, opt
= 380 + j340 (ATA6286N) at 315 MHz and
S
– 0.5V.
Z = 50
Power
meter
50
R
in
4958BS–AUTO–01/09
S
is required to