ATA5773-DK1 Atmel, ATA5773-DK1 Datasheet - Page 9

• Manufacturer Part Number: ATA5773-DK1
• Description: BOARD XMITTER FOR ATA5773 315MHZ
• Manufacturer: Atmel
• Type: Transmitterr

Specifications of ATA5773-DK1

• Frequency: 315MHz
• Maximum Frequency: 315 MHz
• Supply Voltage (max): 4 V
• Supply Voltage (min): 2 V
• Supply Current: 9 mA
• Product: RF Development Tools
• For Use With/related Products: ATA5773
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3.4
3.4.1
3.4.2
9137E–RKE–12/10
CLK Output
Clock Pulse Take-over
Output Matching and Power Setting
Figure 3-1.
Using C
tances on each side of the crystal of C
crystal of C
tion of ±21.5 kHz with worst case tolerances of ±16.25 kHz to ±28.01 kHz.
RF transmitter generated clock signal based on the devided crystal frequency. This will be
available for the microcontroller as reference. The delivered signal is CMOS compatible if the
load capacitance is lower than 10pF.
The clock of the crystal oscillator can be used for clocking the microcontroller, which starts
with an integrated RC-oscillator. After the generated clock signal of the RF transmitter is sta-
ble, the microcontroller will take over the clock signal and use it as reference generating the
data rate, so that the message can be transmitted with crystal accuracy.
The power amplifier is an open-collector output delivering a current pulse, which is nearly
independent from the load impedance. Thus the delivered output power can be tuned via the
load impedance of the antenna and the matching elements. This output configuration enables
simple matching to any kind of antenna or to 50
{ = P
the load impedance is optimized to
• Z
• Z
Load
Load
out
– Background: The current pulse of the power amplifier is 9mA and the maximum
– Background: The current pulse of the power amplifier is 9mA and the maximum
output power is delivered to a resistive load of 400 if the 1.0pF output
capacitance of the power amplifier is compensated by the load impedance. And
thus the load impedance of Z
achieved for the maximum output power of 8dBm.
output power is delivered to a resistive load of 465 if the 1.0pF output
capacitance of the power amplifier is compensated by the load impedance. And
thus the load impedance of Z
is achieved for the maximum output power of 7.5dBm.
/(I
4
= (255 + j192) for the Atmel ATA5773 with the power efficiency of 40%
= (166 + j223) for the Atmel ATA5774 with the power efficiency of 36%
= 8.2 pF ±5%, C
S,PA
0
= 3.2 pF ±10% and a crystal with C
V
Tolerances of Frequency Modulation
S
) }. The maximum output power can be achieved at 3V supply voltage when
XTAL
V
S
5
= 10 pF ±5%, a switch port with C
C
Stray1
Crystal equivalent circuit
Load
Load
C
Stray1
M
= 400 || j/(2
= 465 || j/(2
= C
L
C
M
0
Stray2
M
= 13 fF ±10%, results in a typical FSK devia-
R
S
= 1 pF ±10%, a parallel capacitance of the
which results in a high power efficiency
Atmel ATA5771/73/74
f
f
C
Switch
Stray2
1.0 pF) = (255 + j192) is
C
5
1.0 pF) = (166 + j223)
= 3 pF ±10%, stray capaci-
C
Switch
C
4
9