AT86RF211SAH-R Atmel, AT86RF211SAH-R Datasheet - Page 18

• 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: -

2.2.8
2.2.9
18
AT86RF211S
IF2 Filtering and Gain
IF2 Amplifier Chain
IF2 filtering provides a narrow channel selection. If an IF2 filter is not used, it should be
replaced by a coupling capacitor superior to 1 nF, the IF1 filter therefore being the only
part achieving the channel selection. Available commercial filters with a 35 kHz band-
width provide data rates up to 19.6 kbps if crystal temperature drifts are very low.
For faster communication and/or wider channelization, this ceramic filter can be
replaced by an LC band-pass filter as suggested in Figure 2-12 on page 18.
Figure 2-12. LC Band-pass Filter
The 10 nF capacitors cut the DC response. The first network has the low cut-off fre-
quency and the second network the high cut-off frequency.
The input impedance of the IF2 amplifier is 1700Ω. This value permits use of popular fil-
ters with an impedance between 1500Ω and 2000Ω. The IF2 amplifier is directly
connected to the FSK demodulator. The bandwidth is internally limited to 1 MHz to min-
imize noise entering the discriminator.
The IF2 amplifier acts like a band pass filter centered at 455 kHz with capacitive cou-
pling between the different stages of the amplifier and mixer. The total voltage gain is
typically 86 dB. Thanks to the capacitive coupling, no slow DC feedback loop is needed,
thus enabling the IF2 amplifier to be activated rapidly. IF2DEC must be decoupled with
at least 2.2 nF.
Filter
Gain
10 nF
~ F1
40 kHz or higher
F1
F2
~ F2
Global Response
10 nF
Frequency
5348B–WIRE–03/06