6 blocking, selectivity – Rainbow Electronics ATA5746 User Manual
Page 11

11
4596A–RKE–05/06
ATA5745/ATA5746 [Preliminary]
2.5
RX Supply Current Versus Temperature and Supply Voltage
shows the typical supply current of the receiver in Active mode versus supply voltage
and temperature with VS = VS3V_AVCC = VS5V.
2.6
Blocking, Selectivity
As can be seen in
, and
and
receiver can receive signals 3 dB higher than the sensitivity level in the presence of large block-
ers of –34.5 dBm or –28 dBm with small frequency offsets of ±3 MHz or ±20 MHz.
, and
show the narrow-band blocking, and
shows the wide-band blocking characteristic. The measurements were done with a useful
signal of 315 MHz, FSK, 10 Kbits/s,
±38 kHz, Manchester, BR_Range2 with a level of
–105 dBm + 3 dB = –102 dBm, which is 3 dB above the sensitivity level. The figures show how
much larger than –102 dBm a continuous wave signal can be, until the BER is higher than 10
–3
.
The measurements were done at the 50
Ω input shown in
. At 3 MHz, for
e x a m p l e , t h e b l o c k e r c a n b e 6 7 . 5 d B C h i g h e r t h a n – 1 0 2 d B m , o r
–102 dBm + 67.5 dBC = –34.5 dBm.
Figure 2-6.
Close-in 3-dB Blocking Characteristic and Image Response at 315 MHz
Table 2-6.
Measured Current in Active Mode ASK
VS = VS3V_AVCC = VS5V
2.7V
3.0V
3.3V
T
amb
=
–40°C
5.4 mA
5.5 mA
5.6 mA
T
amb
=
25°C
6.4 mA
6.5 mA
6.6 mA
T
amb
=
105°C
7.4 mA
7.5 mA
7.6 mA
Table 2-7.
Measured Current in Active Mode FSK
VS = VS3V_AVCC = VS5V
2.7V
3.0V
3.3V
T
amb
=
–40°C
5.6 mA
5.7 mA
5.8 mA
T
amb
=
25°C
6.6 mA
6.7 mA
6.8 mA
T
amb
=
105°C
7.6 mA
7.7 mA
7.8 mA
-10.0
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
Distance from Interfering to Receiving Signal (MHz)
B
lo
cki
n
g
L
evel
(
d
B
C
)