RFM210LW Datasheet, PDF (10/17 Pages) List of Unclassifed Manufacturers – Low-Cost Consumer Electronics Applications

5. Functional Descriptions
RFM210LW
RFI
GND
VDD
GND
I-MXR
LNA
Q-MXR
LO GEN
LDOs
Bandgap
POR
Image
Rejection
Band-pass
Filter
I-LMT
RSSI
SAR
AGC
OOK
DEMOD
AFC & AGC
VCO
Q-LMT
Loop
Filter
PFD/CP
26 MHz
DIVIDER
AFC & Σ-Δ Modulator
VCON VCOP nRSTO
Radio
Controller
3-wire SPI
CSB
SCL
SDA
LPOSC
XOSC
EEPROM
CLKO
DOUT
XIN XOUT
Figure 5. Functional Block Diagram
5.1 Overview
The RFM210LW is an ultra low power, high performance, low-cost OOK stand-alone RF receiver for various 300 /
480 MHz wireless applications. It is part of the CMOSTEK NextGenRF^TM family, which includes a complete line of
transmitters, receivers and transceivers. The chip is based on a fully integrated, low-IF receiver architecture. The
low-IF architecture facilitates a very low external component count and does not suffer from powerline - induced
interference problems. The synthesizer contains a VCO and a low noise fractional-N PLL with an output frequency
resolution of 24.8 Hz. The VCO operates at 2x the Local Oscillator (LO) frequency to reduce spurious emissions.
Every analog block is calibrated on each Power-on Reset (POR) to the internal reference voltage. The calibration
helps the device to finely work under different temperatures and supply voltages. The baseband filtering and
demodulation is done by the digital demodulator. The demodulated signal is output to the external MCU via the
DOUT pin. No external MCU control is needed in the applications.
The 3-wire SPI interface is only used for configuring the device. The configuration can be done with the RFPDK and
the USB Programmer. The RF Frequency, symbol rate and other product features are all configurable. This saves
the cost and simplifies the design, development and manufacture. Alternatively, in stock products of 315/433.92
MHz are available for immediate demands with no need of EEPROM programming. The RFM210LW operates from
1.8 to 3.6 V so that it can finely work with most batteries to their useful power limits. The receive current is only 3.8
mA. The RFM210LW receiver together with the CMT211x transmitter enables an ultra low cost RF link.
5.2 Modulation, Frequency and Symbol Rate
The RFM210LW supports OOK demodulation with the symbol rate from 0.1 to 40 kbps. It continuously covers the
frequency range from 300 to 480 MHz, including the license free ISM frequency band around 315 MHz and 433.92
MHz. The internal frequency synthesizer contains a high-purity VCO and a low noise fractional-N PLL with an
output frequency resolution of 24.8 Hz. See Table 9 for the demodulation, frequency and symbol rate information.
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