RFM110W Datasheet, PDF (10/22 Pages) List of Unclassifed Manufacturers – Low-Cost Consumer Electronics Applications

RFM110W/RFM117W
5. Functional Descriptions
VDD
GND
XTAL
CLK
DATA
LDOs
XOSC
POR
Bandgap
VCO
PFD/CP
Loop Filter
PA
Fractional-N
DIV
EEPROM
OOK Modulator
Ramp
Control
Interface and Digital Logic
RFO
5.1 Overview
Figure 11. RFM110W/RFM117W Functional Block Diagram
The RFM110W/RFM117W is an ultra low-cost, highly flexible, high performance, single-chip OOK transmitter for various 240 to
960
MHz wireless applications. The RFM110W covers the frequency range from 240 to 480 MHz while the CMT2117 covers the
240 to 960 MHz frequency range. They are part of the CMOSTEK NextGenRF^TM family, which includes a complete line of
transmitters, receivers and transceivers. The chip is optimized for the low system cost, low power consumption, battery
powered application with its highly integrated and low power design.
The functional block diagram of the RFM110W/RFM117W is shown in the figure above. The RFM110W/RFM117W is
based on direct synthesis of the RF frequency, and the frequency is generated by a low-noise fractional-N frequency
synthesizer. It uses a
1-pin crystal oscillator circuit with the required crystal load capacitance integrated on-chip to minimize the number of external
components. Every analog block is calibrated on each Power-on Reset (POR) to the highly accurate reference voltage
internally. The calibration can help the chip to finely work under different temperatures and supply voltages. The
RFM110W/RFM117W uses the DATA pin for the host MCU to send in the data. The input data will be modulated and sent
out by a highly efficient PA which output power can be configured from -10 to +13 dBm in 1 dB step size. RF Frequency, PA
output power and other product features can be programmed into the embedded EEPROM by the RFPDK and USB
Programmer. This saves the cost and simplifies the product development and manufacturing effort. Alternatively, in stock
products of
433.92/868.35 MHz are available for immediate demands with no need of EEPROM programming. The RFM110W/RFM117W
operates from 1.8 to 3.6 V so that it can finely work with most batteries to their useful power limits. Working under 3.3 V supply
voltage when transmitting signal at +10 dBm power, it only consumes 13.4 mA at 433.92 MHz and 15.5 mA at 868.35 MHz.
5.2 Modulation, Frequency and Symbol Rate
The RFM110W/RFM117W supports OOK modulation with the symbol rate up to 30 ksps. The RFM110W covers the frequency
range from 240 to 480 MHz, while the RFM117W covers the frequency range from 240 to 960 MHz, including the license free
ISM frequency band around 315 MHz, 433.92 MHz, 868.35 MHz and 915 MHz. The device contains a high spectrum purity
low power fractional-N frequency synthesizer with output frequency resolution better than 198 Hz when the frequency is lower
than
480 MHz, and the frequency resolution is 397 Hz when the frequency is higher than 480 MHz. See the table below for the
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