SI4460-C2A-GM Datasheet, PDF (33/53 Pages) Silicon Laboratories – HIGH-PERFORMANCE, LOW-CURRENT TRANSCEIVER

Si4463/61/60-C
The following are example steps for using Auto Hop:
1. Set the base frequency (inte + frac) and channel step size.
2. Define the number of entries in the hop table (RX_HOP_TABLE_SIZE).
3. Write the channels to the hop table (RX_HOP_TABLE_ENTRY_n)
4. Configure the hop condition and enable auto hopping- RSSI, preamble, or sync (RX_HOP_CONTROL).
5. Set preamble and sync parameters if enabled.
6. Program the RSSI threshold property in the modem using “MODEM_RSSI_THRESH”.
7. Set the preamble threshold using “PREAMBLE_CONFIG_STD_1”.
8. Program the preamble timeout property using “PREAMBLE_CONFIG_STD_2”.
9. Set the sync detection parameters if enabled.
10. If needed, use “GPIO_PIN_CFG” to configure a GPIO to toggle on hop and hop table wrap.
11. Use the “START_RX” API with channel number set to the first valid entry in the hop table (i.e., the first non
0xFF entry).
12. Device should now be in auto hop mode.
5.3.1.3. Manual RX Hopping
The RX_HOP command provides the fastest method for hopping from RX to RX but it requires more overhead and
management by the host MCU. The timing is faster with this method than Start_RX or RX hopping because one of
the calculations required for the synthesizer calibrations is offloaded to the host and must be calculated/stored by
the host, VCO_CNT0. For VCO_CNT values, download the Si446x RX_HOP PLL calculator spreadsheet from the
Si446x product website.
5.4. Transmitter (TX)
The Si4463 contains an integrated +20 dBm transmitter or power amplifier that is capable of transmitting from –20
to +20 dBm. The resolution of the programmable steps in output power is less than 0.25 dB when operated within
6 dB of the maximum power setting; the resolution of the steps in output power becomes coarser and more
non-linear as the output power is reduced towards the minimum end of its control range. The Si4463 PA is
designed to provide the highest efficiency and lowest current consumption possible. The Si4460 is designed to
supply +10 dBm output power for less than 20 mA for applications that require operation from a single coin cell
battery. The Si4460 can operate with Class-E matching and output up to +13 dBm Tx power at a supply voltage of
VDD = 3.3 V. All PA options are single-ended to allow for easy antenna matching and low BOM cost. Automatic
ramp-up and ramp-down is automatically performed to reduce unwanted spectral spreading. Refer to “AN627:
Si4460/61 Low-Power PA Matching” and “AN648: PA Matching” for details on TX matching options.
The chip’s TXRAMP pin is disabled by default to save current in cases where the on-chip PA provides sufficient
output power to drive the antenna. In cases where on-chip PA will drive the external PA, and the external PA needs
a ramping signal, TXRAMP is the signal to use. To enable TXRAMP, set the API Property PA_MODE[7] = 1.
TXRAMP will start to ramp up, and ramp down at the SAME time as the internal on-chip PA ramps up/down.
However, the time constant of the TXRAMP signal for the external PA is programmed independently of the ramp
time constant for the on-chip PA. The ramp time constant for TXRAMP is programmed by the TC[3:0] field in the
PA_RAMP_EX API property and provides the following approximate ramp times as a function of TC[3:0] value.
Rev 1.0
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