AMIS-53050 Datasheet, PDF (6/107 Pages) AMI SEMICONDUCTOR – Frequency Agile Transceiver

AMIS-53050 Frequency Agile Transceiver
Data Sheet
1.4 Circuit Overview
1.4.1. Transmitter
In the AMIS-53050, a pre-driver and a class E power amplifier are used to output the OOK- or FSK-modulated radio frequency signals.
The class E power amplifier has two output power ranges aimed at realizing high output power efficiency. The output power level is
programmable, the maximum value for these two ranges being 0dBm and +15dBm, respectively. The class E power amplifier provides
maximum output power of +12dBm to +15dBm in the frequency range of 300MHz to 915MHz.
The transmitted data can be NRZ or Manchester encoded. Data rates for OOK modulation can be as high as 19.2kbps, while data rates
for FSK/GFSK modulation can be as high as 128kbps. The deviation of the RF carrier frequency for the FSK modulation is
programmable, typically being one half to one times the data rate.
The transmit data output can be wave shaped with a Gaussian format. This can reduce the occupied bandwidth of the signal. Power to
the transmitter PA can be ramped during power-up and power-down transitions, respectively, in order to reduce signal frequency
splatter.
1.4.2. Receiver
The AMIS-53050 has single receive and transmit channels, respectively, which can be connected to individual antennas or alternatively
to a single antenna, using external components. A single antenna configuration will have reduced performance, receiver sensitivity
and/or transmit output power. The receiver uses four different methods to receive and recover data that has been on/off shift key or
frequency shift key modulated. The FSK/GFSK data is recovered using either a phase-locked loop (PLL) or a Fast Fourier transform
(FFT) circuit, in conjunction with a clock and data recovery (CDR) circuit. The OOK data is recovered using a received signal strength
indicator (RSSI) circuit. It is suggested that the CDR circuit be used when receiving OOK signals as well.
1.4.2.1. On/Off Shift Key Modulation
The AMIS-53050 uses a logarithmic RSSI detector to recover the data from the on/off shift key modulated waveforms. Data rates can
be as high as 19.2kbps. The device has eight discrete data filters for common baud rates. The receiver can detect either NRZ or
Manchester encoded data. The single Byte command ROM2REGs will change the slice filter settings and the CDR settings when one
of the standard data rates is selected.
1.4.2.2. Low Data Rate Frequency Shift Key Modulation
The AMIS-53050 uses a digital PLL detector to recover the received frequency shift key data below 20kbps. The recovered data
waveform is in turn applied to the CDR circuit to produce the digital data and a synchronized clock. The receiver can detect either NRZ
or Manchester encoded data. The single byte command ROM2REGs will change the CDR settings when one of the standard data rates
is selected.
1.4.2.3. High Data Rate Frequency Shift Key Modulation
An integrated FFT circuit is used to recover the received frequency shift key modulated waveforms when the data rate is higher than
20kbps. The data rate can be as high as 128kbps. The demodulated data waveform is in turn applied to the clock and data recovery
circuit to produce the digital data and a synchronized clock. The receiver can detect either NRZ or Manchester encoded data. The
single byte command ROM2REGs will change the CDR settings when one of the standard data rates is selected.
1.4.2.4. Clock and Data Recovery
The AMIS-53050 uses a CDR circuit that is linked to the frequency shift key or on/off shift key data detector circuits to recover the data
stream. The CDR circuit synchronizes a clock with the data rate of the received data. The CDR function is a critical element for the
recovery of high data rate (>20kbps) FSK signals, while data can be recovered without the CDR function for low data rate FSK and
OOK signals, respectively. It is recommended, however, that the CDR function be used with all receiver data recovery methods.
AMI Semiconductor – Jan. 07, M-20639-002
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