AMIS-52150 Datasheet, PDF (17/25 Pages) AMI SEMICONDUCTOR – Low-Power Transceiver with Clock and Data Recovery

AMIS-52150
Low-Power Transceiver with Clock and Data Recovery
Data Sheet
A “kicker” circuit stimulates the crystal oscillator circuit with oscillations close to the final frequency. This significantly reduces the time it
takes for the oscillator to reach and lock to the final frequency. The Quick Start function is necessary for operation in Sniff Mode^TM.
Table 25 lists the Quick Start control registers. For further details, refer to the application note titled “Quick Start Crystal Oscillator
Circuit Operation and Set-up”.
Table 25: Quick Start Control Registers
Quick Start Control Registers
Register (HEX) Name
0x03
Kicker Trim
0x0e
Kick Config1
Kick Config2
Bits States Comments
All
Trim the internal RC OSC to form a kick-start to the XTAL oscillator
4
0
Common mode clamp disabled (startup)
1
Common mode clamp enabled (normal)
5
0
Normal operation
1
Continuous kick On
9.5 Data Detection
The RSSI circuit creates an analog voltage waveform (18mV/dB) that follows the signal strength of the RF signal. The data slice circuit
then samples that waveform to create the digitized data. The slice circuit in the AMIS-52150 can be programmed to operate in one of
three modes; DAC mode, Average mode or Peak mode. The DAC mode compares a fixed slice threshold value to the level in the slice
output. The digital data state is determined by the level of the slice output being above or below that fixed threshold. For further details,
refer to the application note titled “Setting Up the AMIS-52150 Data Slicing Modes”. Figure 12 shows a typical waveform for the DAC
mode, while Table 26 shows the control registers for the auto slice modes.
Figure 12: DAC Slice Mode Waveform
In the Average mode, the threshold value is generated automatically. This threshold value is then compared to the output of the slice
circuit to re-create the digital data. The slice circuit along with an external capacitor are used to generate a charging time constant
which is equal to charging to 95 percent of a bit level in two bit time periods. The data protocol should add a header to the data to allow
the slice circuit to determine the average level. For further details, refer to the application note titled “Setting Up the AMIS-52150 Data
Slicing Modes”. Figure 13 shows a typical waveform for the Average mode. Table 26 shows the control registers for the auto slice
modes.
AMI Semiconductor – Apr. 07 – M-20535-006
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