ATA5423_06 ATMEL [ATMEL Corporation], ATA5423_06 Datasheet - Page 20

• Manufacturer Part Number: ATA5423_06
• Description: UHF ASK/FSK Transceiver
• Manufacturer: ATMEL [ATMEL Corporation]

Figure 3-9.
3.12
20
Output Power Setting and PA Matching at RF_OUT
ATA5423/25/28/29
Ref 10 dBm
Samp
Log
10
dB/
VAvg
50
W1 S2
S3 FC
Center 433.92 MHz
Res BW 10 kHz
FSK-modulated TX Spectrum (433.92 MHz/20 Kbit/s/±16.17 kHz/Manchester Code)
The Power Amplifier (PA) is a single-ended open collector stage which delivers a current pulse
which is nearly independent of supply voltage, temperature and tolerances due to band gap sta-
bilization. Resistor R
current in the PA. A higher resistor value results in a lower reference current, a lower output
power and a lower current consumption of the PA. The usable range of R
PWR_H switches the output power range between about 0 dBm to 5 dBm (PWR_H = GND) and
5 dBm to 10 dBm (PWR_H = AVCC) by multiplying this reference current by a factor 1
(PWR_H = GND) and 2.5 (PWR_H = AVCC), which corresponds to about 5 dB more output
power.
If the PA is switched off in TX mode, the current consumption without output stage with
VS1 = VS2 = 3 V, T
433.92 MHz.
The maximum output power is achieved with optimum load resistances R
3-7 on page 22
absorbing it into the matching network consisting of L
21. There must also be a low resistive DC path to AVCC to deliver the DC current of the power
amplifier's last stage. The matching of the PA output was done with the circuit shown in
3-10 on page 21
ments may be necessary to compensate for individual board layouts.
Atten 20 dB
with compensation of the 1.0 pF output capacitance of the RF_OUT pin by
with the values in
amb
1
, see
= 25°C is typically 6.5 mA for 868.3 MHz and 6.95 mA for 315 MHz and
VBW 10 kHz
Figure 3-10 on page
Table 3-7 on page
21, sets a reference current which controls the
1
, C
22. Note that value changes of these ele-
1
, C
Sweep 27.5 ms (401 pts)
Span 1 MHz
3
as shown in
1
Lopt
is 15 kΩ to 56 kΩ. Pin
Figure 3-10 on page
according to
4841C–WIRE–05/06
Figure
Table