TXC101 RFM, TXC101 Datasheet - Page 11

• Manufacturer Part Number: TXC101
• Description: IC TX 300MHZ-1GHZ 16-TSSOP
• Manufacturer: RFM
• Series: TXr

Specifications of TXC101

• Frequency: 300MHz ~ 1GHz
• Applications: General Data Transfer
• Modulation Or Protocol: FSK, OOK
• Data Rate - Maximum: 512kbps
• Power - Output: 3dBm
• Current - Transmitting: 13mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 2.2 V ~ 5.4 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 16-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Memory Size: -
• Other names: 583-1098-2

Output Power Amplifier
The power amplifier is an open-collector, differential output with programmable output power which can
directly drive a loop or dipole antenna, and with proper matching may also drive a monopole antenna.
Incorporated in the power amplifier is an automatic antenna tuning circuit to avoid manual tuning during
production and to offset “hand effects”. Registers common to the Power Amplifier are:
Phase Lock Loop (PLL)
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.
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:
Transmit Register
The transmit register is configured as two 8-bit shift registers connected in series to form a single 16-bit
shift register. This register is a master when in EEPROM Mode. The TXC101 generates the chip select
and clock to read the EEPROM contents into the register.
For Microcontroller Mode, this register is not available. Data may be applied in two ways: directly to the
FSK MOD pin (16) after enabling the oscillator, synthesizer, and power amplifier, or directly to the SDI pin
following the clock timing on page 19 of the Transmit Command Register.
Crystal Oscillator
The TXC101 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.
Since the crystal is the PLL reference for the carrier, being able to vary the load capacitance also helps
with fine tuning the final carrier frequency
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, thus also disabling 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.
Sleep Mode
The TXC101 draws very little current when in sleep mode (200nA typical). See the Power Management
Register and Sleep/Clock Command Register definitions on how to program the TXC101 into full sleep
mode.
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©by RF Monolithics, Inc.
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Power Management Register
Transmit Power Configuration Register
Power Management Register
Configuration Register
Frequency Setting Register
Transmit Configuration Register
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TXC101 - 4/8/08
Page 11 of 27