TRC101 RFM, TRC101 Datasheet - Page 9

• Manufacturer Part Number: TRC101
• Description: RFIC TRANCEIVER MULTI-CHANNEL FS
• Manufacturer: RFM
• Series: TRCr

Specifications of TRC101

• Frequency: 300MHz ~ 1GHz
• Data Rate - Maximum: 256kbps
• Modulation Or Protocol: FSK
• Applications: General Purpose
• Power - Output: 8dBm
• Sensitivity: -105dBm
• Voltage - Supply: 2.2 V ~ 5.4 V
• Current - Receiving: 17mA
• Current - Transmitting: 28mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 16-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Other names: 583-1093-2

The FIFO can be read out through the SDO pin only by pulling the nFSEL pin (6) ‘Low” which selects the
FIFO for read and reading out data on the next SPI clock. The FINT pin (7) will stay active (logic ‘1’) until
the last bit has been read out, and it will then go ‘low’. This pin may also be polled to watch for valid data.
When the number of bits received in the FIFO match the pre-programmed limit, this pin will go active
(logic ‘1’) and stay active until the last bit is read out as above. An alternative method of reading the FIFO
is through an SPI bus Status Register read. The drawback to this is that all interrupt and status bits must
be read first before the FIFO bits appear on the bus. This could pose a problem for receiving large
amounts of data. The best method is using the SDO pin and the associated FIFO function pins.
Automatic Frequency Adjustment (AFA)
The PLL has the capability to do fine adjustment of the carrier frequency automatically. In this way, the
receiver can minimize the offset between transmit and receive frequency. This function may be enabled
or disabled through the Automatic Frequency Adjustment Register. The range of offset can be
programmed as well as the offset value calculated and added to the frequency control word within the
PLL to incrementally change the carrier frequency. The chip can be programmed to automatically
perform an adjustment or may be manually activated by a strobe signal. This function has the advantage
of allowing:
Crystal Oscillator
The TRC101 incorporates an internal crystal oscillator circuit that provides a 10MHz reference, as well as
internal load capacitors. This significantly reduces the component count required. The internal load
capacitance is programmable from 8.5pF to 16pF in 0.5pF steps. This has the advantage of accepting a
wide range of crystals from many different manufacturers having different load capacitance requirements.
Being able to vary the load capacitance also helps with fine tuning the final carrier frequency since the
crystal is the PLL reference for the carrier.
An external clock signal is also provided that may be used to run an external processor. This also has
the advantage of reducing component count by eliminating an additional crystal for the host processor.
The clock frequency is also programmable from eight pre-defined frequencies, each a pre-scaled value of
the 10MHz crystal reference. These values are programmable through the Battery Detect Threshold and
Clock Output Register. The internal clock oscillator may be disabled which also disables the output clock
signal to the host processor. When the oscillator is disabled, the chip provides an additional 196 clock
cycles before releasing the output, which may be used by the host processor to setup any functions
before going to sleep.
Frequency Control (PLL) and Frequency Synthesizer
The PLL synthesizer is the heart of the operating frequency. It is programmable and completely
integrated, providing all functions required to generate the carriers and tunability for each band. The PLL
requires only a single 10MHz crystal reference source. RF stability is controlled by choosing a crystal
with the particular specifications to satisfy the application. This gives the designer the maximum flexibility
in performance.
The PLL is able to perform manual and automatic calibration to compensate for changes in temperature
or operating voltage. When changing band frequencies, re-calibration must be performed. This can be
done by disabling the synthesizer and re-enabling again through the Power Management Register.
Registers common to the PLL are:
Data Quality Detector (DQD)
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©by RF Monolithics, Inc.
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Power Management Register
Configuration Register
Frequency Setting Register
Automatic Frequency Adjust Register
Transmit Configuration Register
Low cost lower accuracy crystals to be used
Increased receiver sensitivity by narrowing the receive bandwidth
Achieving higher data rates
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TRC101 - 4/8/08
Page 9 of 42