RFM119W/RFM119SW

Rev 1.0 | Page 9 /19

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LDOs

POR

Bandgap

5. Functional Descriptions

VDD

GND

XTAL

XOSC

PFD/CP

Loop Filter

VCO

PA

RFO

Fractional-N

DIV

EEPROM

Modulator

Ramp

Control

CLK

DATA

Interface and Digital Logic

Figure 11. RFM119W/RFM119SW Functional Block Diagram

5.1 Overview

The RFM119W/RFM119SW is a high performance, highly flexible, low-cost, single-chip (G)FSK/OOK transmitter for various 240

to 960

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 RFM119W/RFM119SW is shown in the figure above. The RFM119W/RFM119SW 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 internal voltage

reference. The calibration can help the chip to finely work under different temperatures and supply voltages. The

RFM119W/RFM119SW 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

The user can directly use the RFM119W/RFM119SW default configuration for immediate demands. If that cannot meet the

system requirement, on-line register configuration and off-line EEPROM programming configuration are available for the user

to customize the chip features. The on-line configuration means there is an MCU available in the application to configure the

chip registers through the 2-wire interface, while the off-line configuration is done by the HOPERF USB Programmer and the

RFPDK. After the configuration is done, only the DATA pin is required for the host MCU to send in the data and control the

transmission. The RFM119W/RFM119SW operates from 1.8 to 3.6 V so that it can finely work with most batteries to their

useful power limits. It only consumes 15.5 mA (OOK @ 868.35 MHz) / 27.6 mA (FSK @ 868.35 MHz) when transmitting +10

dBm power under 3.3 V supply voltage.

5.2 Modulation, Frequency, Deviation and Symbol Rate

The RFM119W/RFM119SW supports GFSK/FSK modulation with the symbol rate up to 100 ksps, as well as OOK modulation

with the symbol rate up to 30 ksps. The supported deviation of the (G)FSK modulation ranges from 1 to 200 kHz. The

RFM119W/RFM119SW continuously 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 less than 480 MHz, and is about 397 Hz