AT86RF211SAH-R Atmel, AT86RF211SAH-R Datasheet - Page 15

• Manufacturer Part Number: AT86RF211SAH-R
• Description: IC RF TXRX FSK 400-950MHZ 48TQFP
• Manufacturer: Atmel

Specifications of AT86RF211SAH-R

• Frequency: 400MHz ~ 950MHz
• Data Rate - Maximum: 100kbps
• Modulation Or Protocol: FSK
• Applications: ISM
• Power - Output: 7dBm ~ 12dBm
• Sensitivity: -107dBm
• Voltage - Supply: 2.4 V ~ 3.6 V
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-TQFP Exposed Pad, 48-eTQFP, 48-HTQFP, 48-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Memory Size: -
• Current - Transmitting: -
• Current - Receiving: -

2.2.3
Figure 2-6.
2.2.4
5348B–WIRE–03/06
Image Rejection and RF Filter
First LNA/Mixer
Typical 50Ω SAW Filter Implementation in the 868 MHz Bandwidth
SWOUT (pin 48)
SPST Switch
The immunity of the AT86RF211S can be improved with an external band-pass filter.
For example, when using a SAW filter, it must be matched with the LNA input and the
output of the switch. The following diagram gives the typical implementation for an
868 MHz application with a 50Ω/50Ω SAW filter.
See Table 2-2 on page 15 for precise matching information and the Application Note
“AT86RF211S FSK Transceiver for ISM Radio Applications - RF BOM vs. Application
Requirements” reference 5305, for suggested matching filters.
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 2-2.
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. Usually 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 Table 2-2.
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 filter provides such a link.
2.2 nH
Frequency Band
1. RXIN: impedance to be seen by LNA input for NF optimization purposes
2. SWOUT: output impedance of the RF switch
433 MHz
868 MHz
915 MHz
Matching Information
These inductors can be printed
SAW
50 Ω
35 + j 170Ω
37 + j 85 Ω
30 + j 85 Ω
RXIN
12 nH
(1)
(pin 45)
RXIN
AT86RF211S
24 - j 43 Ω
50 - j 42 Ω
50 - j 42 Ω
SWOUT
(2)
15