ATA5811_06 ATMEL [ATMEL Corporation], ATA5811_06 Datasheet - Page 10

• Manufacturer Part Number: ATA5811_06
• Description: UHF ASK/FSK TRANSCEIVER
• Manufacturer: ATMEL [ATMEL Corporation]

5.2
10
Input Matching at RF_IN
ATA5811/ATA5812
The measured input impedances as well as the values of a parallel equivalent circuit of these
impedances can be seen in
of these impedances to the source impedance of 50 .
Table 5-1.
The matching of the LNA Input to 50 was done with the circuit according to
the values given in
changes of C
sured typical FSK and ASK Manchester code sensitivities with a Bit Error Rate (BER) of 10
shown in
inductors having a quality factor according to
of 1.0 dB at 315 MHz, 1.2 dB at 433.92 MHz and 0.6 dB at 868.3 MHz. These losses can be
estimated when calculating the parallel equivalent resistance of the inductor with
R
With an ideal inductor, for example, the sensitivity at 433.92 MHz/FSK/20 Kbit/s/
±16 kHz/Manchester can be improved from –106 dBm to –107.2 dBm. The sensitivity depends
on the control logic which examines the incoming data stream. The examination limits must be
programmed in control registers 5 and 6. The measurements in
page 11
Figure 5-1.
Table 5-2.
loss
= 2
f
are based on the values of registers 5 and 6 according to
433.92
RF
Table 5-3 on page 11
868.3
315
/MHz
f
433.92
RF
868.3
1
315
/MHz
Measured Input Impedances of the RF_IN Pin
Input Matching to 50
Input Matching to 50
and L
f
L
Table
1
may be necessary to for compensate individual board layouts. The mea-
Q
L
5-2. The reflection coefficients were always
and the matching loss with 10 log(1+R
Table
RF
and
IN
C
2.2
1.8
1.2
1
5-1. The highest sensitivity is achieved with power matching
/pF
Table 5-4 on page
C
1
L
(44-j233)
(32-j169)
Z(RF_IN)
(21-j78)
1
Table
4
ATA5811/ATA5812
RF_IN
5-2, resulting in estimated matching losses
11. These measurements were done with
L
1
6.8
56
27
/nH
p
/R
Table 11-3 on page
Table 5-3
loss
).
1278 //2.1 pF
925 //2.1 pF
311 //2.2 pF
10 dB. Note that value
R
Figure 5-1
p
and
//C
p
4689F–RKE–08/06
Table 5-4 on
Q
43
40
58
L1
58.
and with
-3
are