AT86RF211SAHW Atmel, AT86RF211SAHW Datasheet - Page 14

• Manufacturer Part Number: AT86RF211SAHW
• Manufacturer: Atmel

Specifications of AT86RF211SAHW

• Lead Free Status / Rohs Status: Compliant

4.2.4
14
0894C–WIRE–11/08
First LNA/Mixer
The LNA mixer exhibits a gain of approximately 17 dB (13 dB if the reduced gain is selected) over a 1.2
GHz bandwidth. Its noise figure is typically 9 dB at 900 MHz (10 dB with a minimum gain) when optimum
matching is realized on pin 45.
Table 4-3.
Notes:
The gain is programmable through the CTRL1[25] register (6 dB attenuation when the minimum gain is
selected). The matching choice of the switch and LNA depends mainly on the choice of SAW filter. Usu-
ally the in/out impedance of the SAW filter is 50Ω, but other SAW filters can be implemented and the
matching network recalculated by using the impedance information in
The LNA is directly coupled to the first mixer. The inputs and outputs of the LNA and mixer respectively
must be connected through a capacitive link because of their internal DC coupling. A SAW or ceramic fil-
ter provides such a link.
Figure 4-7.
Figure 4-8.
Frequency Band
433 MHz
868 MHz
915 MHz
1. RXIN: impedance to be seen by LNA input for NF optimization purposes
2. SWOUT: output impedance of the RF switch
Matching Information
Schematic Input of the LNA
Schematic Output of the Mixer
RXIN
35 + j 170Ω
37 + j 85 Ω
30 + j 85 Ω
(1)
RXIN
SWOUT
24 - j 43 Ω
50 - j 42 Ω
50 - j 42 Ω
IF1OUT
(2)
Table
4-3.
e2v semiconductors SAS 2008
AT86RF211S