AT86RF211SAHWR E2V, AT86RF211SAHWR Datasheet - Page 21

• Manufacturer Part Number: AT86RF211SAHWR
• Manufacturer: E2V

Specifications of AT86RF211SAHWR

• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Modulation Type: FSK
• Product Depth (mm): 7mm
• Product Length (mm): 7mm
• Operating Supply Voltage (typ): 2.5/3.3V
• Operating Supply Voltage (max): 3.6V
• Lead Free Status / Rohs Status: Compliant

4.2.12
4.2.12.1
Figure 4-17. Example of Rx Timing with Discharge
e2v semiconductors SAS 2008
SKFI LT
VOLTAGE
Voltage of
Discout Pin
Data Slicer
External Mode
Given below are examples of possible configurations in the 600 kHz-wide 868 to 868.6 MHz European
sub-band, in which the European standard EN 300 220 is applicable:
For further details, please refer to the Application Note “Data Demodulation and Crystal Selection for the
AT86RF211S”.
The analog signals at the discriminator’s output (DISCOUT, pin 27) are converted into CMOS level data
by a high resolution comparator called a data slicer.
The data slicer has a reference for its comparator that can be chosen using CTRL1[4]. The reference
sets the comparator’s comparison level. One option is to extract the average value of the demodulated
signal on the SKFILT pin (pin 25), described below as the external mode. The other option is to set an
absolute value for this reference, described below as the internal mode.
The external mode takes the average value of the demodulated signal as the comparison level for the
comparator. There must be sufficient transitions in the message to ensure that the average value
remains between the 0 and 1 levels. Manchester encoding can be used in this mode as well as DC-free
encoding schemes. The choice of SKFILT capacitor value is a trade-off between the maximum duration
of a constant bit (whether 0 or 1) and the maximum allowed settling time to charge this capacitor after
power-up.
When switching from Rx mode to Tx mode or PDN mode: the pin 25 is shorted to ground, with an inter-
nal switch. The result is a fast discharge of SKFILT capacitor. Switching back to Rx mode: as the SKFILT
cap has been fully discharged, the user should take into account the relevant time to be ready for receiv-
ing data. For instance, a preamble might be received to settle the comparison threshold at the right level.
Notes:
• SDB: 4 channels at 19.200 bps
• MDB: 2 channels at 5.000 bps
• WDB: 1 channel at 100.000 bps
1. It is possible to hold the level on SKFILT capacitor thanks to the charge and hold capability that has
2. Internal data slicer threshold can also be implemented. In this mode, the comparison level is generated
been implemented on the AT86RF211S. Please contact the technical support for further
internally with a DAC. Please refer to
and Crystal Selection for the AT86RF211S” (reference 5418) to implement this in the best way.
Rx Mode
Tx or P DNM ode
Section 4.2.12.2
and the Application Note, “Data Demodulation
Threshold is OK
0894C–WIRE–11/08
AT86RF211S
Rx Mode
information.
21