AT86RF211DB-868LNA Atmel, AT86RF211DB-868LNA Datasheet - Page 8

• Manufacturer Part Number: AT86RF211DB-868LNA
• Description: DAUGHTER BOARD W/ANTENNA 868MHZ
• Manufacturer: Atmel

Specifications of AT86RF211DB-868LNA

• Mfg Application Notes: SmartRF Series Application Note
• Module/board Type: Daughter Board
• For Use With/related Products: AT86RF211 @ 866MHz
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: AT86RF211DB868LNA

Post Filter between DISCOUT
and DSIN
Use of Different Data Rates
After Wake-up (switch between
'external'/'internal' mode)
Use of RSSI Threshold and
Hysteresis
8
AT86RF211 (TRX01)
Atmel recommends using:
•
•
Note:
The purpose of a post-filtering between DISCOUT and DSIN is to remove potential high-
frequency noise on the demodulated signal. The filter also shapes the demodulated sig-
nal and smoothes the edges of the bits.
As the wake-up mode must be used with sharp transition levels, the cut-off frequency of
the filter must not be too close to the equivalent transition frequency of the expected
data rate. The rule-of-thumb, considering a 1
rate (kbps). For instance, at 10 kbps, the post-filter cut-off frequency should not be lower
than 10 kHz.
During the normal communication receive mode (after wake-up phase), it can be lower:
Freqcut-off (kHz) = ½ Data rate (kbps), but not during the wake-up procedure.
As indicated before, it is possible to run a higher data rate when the system has been
woken up, if more data are to be exchanged between two modules. The AT86RF211
may be switched from the "external mode" to the "internal mode" by setting the CTRL[4]
register of the AT86RF211 to '1', and setting up the DTR register accordingly (see
DataSlicer application note for more information).
At the end of WL1, RSSI threshold and hysteresis are used the same way as with the
normal communication receive mode:
•
•
[(C1 = 5.6 nF + R1 = 3.3 kΩ) // C2 = 560 pF] if the maximum data rate of the
application (wake-up phase + data transfer afterwards) does not exceed 10 kbps.
[(C1 = 1 nF + R1 = 10 kΩ) // C2 = 100 pF] if the data rate during the data transfer
exceeds 10 kbits/s. This filter also works well during the wake-up phase
(< 10 kbits/s) as the difference is mainly observed on the phase noise, not on the
rising/falling edges of the signal.
defined in CTRL1[23-15].
threshold levels = TRSSI-HRSSI and TRSSI+HRSSI.
refer to the datasheet of the AT86RF211 for more information.
[(C1 = 2.2 nF + R1 = 14.7 kΩ) // C2 = 220 pF] can also be used for very narrow band
applications.
st
order filter, is: Freqcut-off (kHz) = Data
2186A–WIRE–08/02