ATA5423 ATMEL Corporation, ATA5423 Datasheet - Page 23

• Manufacturer Part Number: ATA5423
• Manufacturer: ATMEL Corporation

3.14
4841A–RKE–02/05
RX/TX Switch
Table 3-9
3.0 V/25°C. As can be seen, a temperature change to –40°C as well as to +85°C reduces the
power by less than 1 dB due to the band gap regulated output current. Measurements of all the
cases in
relative behavior as shown in
Table 3-9.
The RX/TX switch decouples the LNA from the PA in TX mode, and directs the received power
to the LNA in RX mode. To do this, it has a low impedance to GND in TX mode and a high
impedance to GND in RX mode. To design a proper RX/TX decoupling, a linear simulation tool
for radio frequency design together with the measured device impedances of
11,
element values have to be found on–board.
of the switch. The principal switching operation is described here according to the application of
Figure 2-1 on page
Table 3-10.
Figure 3-11. Equivalent Circuit of the Switch
Table 3-7 on page
T
T
T
amb
amb
amb
433.92
Frequency
868.3
Table 3-7 on page 22
315
345
915
VS =
=
= +25°C
= +85°C
shows the relative changes of the output power of a typical device compared to
–
MHz
MHz
MHz
40°C
MHz
MHz
Measurements of Typical Output Power Relative to 3 V/25°C
Impedance of the RX/TX Switch RX_TX2 Shorted to GND
7. The application of
22,
Table 3-10
Table
over temperature and supply voltage have shown about the same
–
–
–
2.4 V
2.4 dB
1.6 dB
2.4 dB
Z(RX_TX1) TX Mode
ATA5423/25/28/29 [Preliminary]
3-9.
2.5 pF
(4.8 + j3.2)
(4.5 + j4.3)
11
and
(5 + j9)
Figure 2.2 on page 8
TBD
TBD
Table 3-11 on page 24
Figure 3-11
1.6 nH
RX_TX1
TX
5
shows an approximate equivalent circuit
–
–
3.0 V
0.7 dB
0.8 dB
0 dB
works similarly.
should be used, but the exact
Z(RX_TX1) RX Mode
(11.3
(10.3
(8.9
TBD
TBD
–
–
–
Table 3-1 on page
j214)
j153)
j73)
+0.9 dB
+0.1 dB
3.6 V
0 dB
23