RFM22 Datasheet, PDF (147/150 Pages) –

RFM22
16. Errata Details
1. Description: The TX Output Power is 18.5 dBm compared to the data sheet limit of 20 dBm.
Impact: Will have impact on range compared to transmitter at +20 dBm.
Workaround: No workaround exists in the current silicon.
Resolution: Will be fixed in the next revision.
2. Description: A spur can be located at half of the output TX frequency with a maximum value of  55 dBc.
Impacts: There is no effect on the performance of the radio, but the spur may effect ETSI compliance.
Workaround: ETSI compliance is radiated so a typical antenna will likely attenuate the spur to be below the
required limit. Testing by Silicon Labs on the recommended reference design using the antenna supplied with
the evaluation kits shows the device passes the ETSI unwanted emissions limits with margin.
Resolution: Will be fixed in the next revision.
3. Description: Spurious tones appear when tuned to a frequency that is within a 100 kHz of a frequency that is a
multiple of 5 MHz, i.e., 900 MHz ±100 kHz, 905 MHz ±100 kHz.
Impacts: The RX sensitivity has not shown degradation but the TX spectrum exhibits spurious tones.
Workaround: Avoid using channels within 100 kHz of frequencies that are multiples of 5 MHz.
Resolution: Will be fixed in the next revision.
4. Description: The general purpose ADC does not functional in differential mode.
Impacts: Only able to use the general purpose ADC in single-ended mode.
Workaround: No work-around exists.
Resolution: Will be fixed in the next revision.
5. Description: RX current does not meet specified value in data sheet .
Impacts: The battery life may be affected.
Workaround: Use the recommend register settings to adjust the current consumption.
Resolution: Problem will be addressed in a future die revision.
6. Description: Additional tuning steps are required for proper RX mode operation.
Impacts: Tuning can fail if additional steps are not implemented in customer firmware.
Workaround: The following steps should be followed to ensure proper operation:
1. Program desired RX frequency minus 937.5 kHz: Program registers 75h, 76h, and 77h
2. Program tune mode: Program register 07h bit 1 (pllon = 1)
3. Disable VCO calibration: Program register 55h bit 0 (skipvco = 1)
4. Program desired RX frequency: Program registers 75h, 76h, and 77h
5.Program RX mode: Program register 07h bit 2 (rxon = 1)
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