ATA5745 ATMEL Corporation, ATA5745 Datasheet - Page 6

• Manufacturer Part Number: ATA5745
• Description: Uhf Ask/fsk Receiver
• Manufacturer: ATMEL Corporation

2.2
6
Input Matching at LNA_IN
ATA5745/ATA5746 [Preliminary]
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.
Table 2-1.
The matching of the LNA input to 50 is done using the circuit shown in
ues of the matching elements given in
board layout parasitics. The measured typical FSK and ASK Manchester-code sensitivities with
a bit error rate (BER) of 10
ments were done with wire-wound inductors having quality factors reported in
resulting in estimated matching losses of 0.8 dB at 315 MHz and 433.92 MHz. These losses can
be estimated when calculating the parallel equivalent resistance of the inductor with
R
Figure 2-1.
Table 2-2.
–10 dB. Note that value changes of C1 and L1 may be necessary to compensate individual
loss
= 2
f
RF
433.92
315
[MHz]
f
RF
433.92
315
[MHz]
Measured Input Impedances of the LNA_IN Pin
Input Matching to 50
Input Matching to 50
f
L
Q
L
and the matching loss with 10 log(1+R
–3
Table
are shown in
RF
C
IN
1
2.2
2.2
2-1. The highest sensitivity is achieved with power matching
[pF]
C1
Z
(72.4 – j298)
In
L1
(55 – j216)
Table
(RF_IN) [ ]
Table 2-3
14
2-2. The reflection coefficients were always
ATA5745/ATA5746
LNA_IN
and
L
Table 2-4 on page
1
68
36
[nH]
In_p
/ R
loss
R
Figure 2-1
In_p
1300 //1.60
900 //1.60
).
//C
7. These measure-
In_p
4596B–RKE–06/07
[pF]
Q
20
15
and the val-
L1
Table
2-2,