Rainbow Electronics ATA5746 - Manual (Page 11)

11
4596A–RKE–05/06
ATA5745/ATA5746 [Preliminary]
2.5 RX Supply Current Versus Temperature and Supply Voltage
Table 2-7 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 Figure 2-6 on page 11 , and Figure 2-7 and Figure 2-8 on page 12 , the
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.
Figure 2-6 , and Figure 2-7 on page 12 show the narrow-band blocking, and Figure 2-8 on page
12 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
Figure 2-1 on page 6
. 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
)