SX1240ISTRT Semtech, SX1240ISTRT Datasheet - Page 3

• Manufacturer Part Number: SX1240ISTRT
• Description: IC, RF/IF TRANSMITTER, 868.3MHz, SOIC-8
• Manufacturer: Semtech

Specifications of SX1240ISTRT

• Transmitting Current: 16.5mA
• Data Rate: 100Kbps
• Modulation Type: FSK, OOK
• Rf Ic Case Style: SOIC
• No. Of Pins: 8
• Supply Voltage Range: 1.8V To 3.7V
• Operating Temperature Range: -40°C To +85°C
• Rohs Compliant: Yes

This product datasheet contains a detailed description of the SX1240 performance and functionality.
1. General Description
The SX1240 is a fully-integrated frequency-agile, single chip transmitter IC capable of FSK and OOK modulation of an
input data stream. The full application circuit is shown in Figure 9. The SX1240 is configured, by default, to operate without
a microcontroller with its pre-configured RF settings (see Section 3 for precise details of the default settings). Selection is
made between 434 MHz and 868 MHz band operation by setting the Control pin (6) either high or low at power-up. A full
description of this functionality is given in Section 3.1.
Where greater flexibility is required, many of the default communication parameters can be dynamically configured. This
includes the operating frequency, frequency deviation and modulation format. Upon the application of a serial clock to the
Control pin (6), the Data pin (2) can be used to load a single 13-bit control word. Accessing this functionality is subject to
the connection of the control pin at start-up. For full details of this, the configuration bits and the precise timing operations
of this functionality please consult Section 3.2.
The SX1240 is designed for use with a variety of low-cost antenna technologies. A reference design with PCB-trace
antenna is presented in Section 5.
Another key feature of the SX1240 is its low current consumption in transmit and sleep modes and its wide voltage
operating range from 1.8 V to 3.7 V. This makes the SX1240 suitable for low-cost battery chemistries or energy harvesting
applications.
The internal architecture of the SX1240 is shown in Figure 1. The SX1240 comprises a low-consumption PLL and power
amplifier. For frequency modulation the modulation is performed digitally within the PLL bandwidth. OOK Modulation is
performed via ramping of the PA reference DAC.
1.1. Pin Diagram
SX1240, Rev 1, Oct 2010
©2010 Semtech Corp.
ADVANCED COMMUNICATIONS & SENSING
Figure 1. Pinouts, Top View
Page 3
Integrated Transmitter IC
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SX1240