|
Semtech |
WIRELESS, SENSING & TIMING
SX1238 - Fully Integrated Transceiver with +27dBm TX Power
SX1238
DATASHEET
VDD2 RXEN MODE RX RFI
PREAMP
VBAT1&2
VR_ANA
VR_DIG
LNA
Power Distribution System
Single to
Differential
Mixers
RC
Oscillator
ANT
IND
PA
PA0
Ramp &
Control
VDD1 PAout PDET TXEN TX RFO VR_PA
Preamp/PA
Tank
Inductor
Loop
Filter
Division by
2,4, or 6
Frac-N PLL
Synthesizer
XO
32 MHz
RSSI AFC
XTAL
GND
Frequency Synthesis
Transmitter Blocks
Receive Blocks
Control Blocks
Primary Analog
Primary Digital
RESET
SPI
RXTX
DIO0
DIO1
DIO2
DIO3
DIO4
DIO5
GENERAL DESCRIPTION
The SX1238 is a fully integrated ISM band transceiver
optimized for use in the (FCC Part 15) 915 MHz band in the
US and 868 MHz band in Europe with a minimum of
external components. It offers a combination of high link
budget and low current consumption in all operating modes.
The 150 dB link budget is achieved by a low noise CMOS
receiver front end and up to +27 dBm of transmit output
power. This is made possible by a fully integrated front end
consisting of a TR Switch, LNA and efficient PA. This makes
SX1238 ideal for applications requiring extended range,
high link budget, or operation in the presence of high
interference.
The Low-IF architecture of the SX1238 sees fast transceiver
start times and demodulation predicated towards low
modulation index and Gaussian filtered spectrally efficient
modulation formats.
APPLICATIONS
Automated Meter Reading
Wireless Sensor Networks
Home and Building Automation
Wireless Alarm and Security Systems
Industrial Monitoring and Control
KEY PRODUCT FEATURES
+27 dBm - 500 mW RF output power
+27 dBm high efficiency PA
Programmable bit rate up to 300kbps
High sensitivity: -124 dBm at 1.2 kbps
863 - 870 MHz and 902 - 928 MHz
80 dB blocking Immunity
Low current, 100nA register retention
Fully integrated synthesizer with a resolution of 61 Hz
FSK, GFSK, MSK, GMSK and OOK modulations
Built-in bit synchronizer performing clock recovery
Sync word recognition
Preamble detection
115 dB+ dynamic range RSSI
Automatic RF sense with ultra-fast AFC
Packet engine up to 64 bytes with CRC
Built-in temperature sensor and low battery indicator
ORDERING INFORMATION
Part Number
SX1238IMLTRT
Delivery
Tape & Reel
MOQ / Multiple
3000 pieces
MLPQ 40 Package - Operating Range [-40;+85°C]
Pb-free, Halogen free, RoHS/WEEE compliant product
SX1238 Rev.2, June 2014
©2014 Semtech Corp.
Page 1
www.semtech.com
SX1238
High Power Transceiver IC
WIRELESS, SENSING & TIMING
Table of contents
DATASHEET
Section
Page
1. General Description ................................................................................................................................................ 6
1.1. Simplified Block Diagram ................................................................................................................................ 6
1.2. Pin and Marking Diagram .................................................................................................................................7
1.3. Pin Description .................................................................................................................................................8
2. Electrical Characteristics....................................................................................................................................... 10
2.1. ESD Notice.................................................................................................................................................... 10
2.2. Absolute Maximum Ratings .......................................................................................................................... 10
2.3. Operating Range........................................................................................................................................... 10
2.4. Chip Specification ...........................................................................................................................................11
2.4.1. Power Consumption............................................................................................................................... 11
2.4.2. Frequency Synthesis.............................................................................................................................. 11
2.4.3. Receiver ................................................................................................................................................. 12
2.4.4. Transmitter ............................................................................................................................................. 13
2.4.5. Front End Control.................................................................................................................................. 14
2.4.6. Digital Specification................................................................................................................................ 15
3. Chip Description.................................................................................................................................................... 16
3.1. Power Supply Strategy.................................................................................................................................. 17
3.2. Low Battery Detector..................................................................................................................................... 17
3.3. Frequency Synthesis..................................................................................................................................... 17
3.3.1. Reference Oscillator............................................................................................................................... 17
3.3.2. CLKOUT Output ......................................................................................................................................18
3.3.3. PLL Architecture..................................................................................................................................... 18
3.3.4. RC Oscillator .......................................................................................................................................... 20
3.4. Transmitter Description .....................................................................................................................................21
3.4.1. Architecture Description ......................................................................................................................... 21
3.4.2. Bit Rate Setting ...................................................................................................................................... 21
3.4.3. FSK Modulation...................................................................................................................................... 22
3.4.4. OOK Modulation..................................................................................................................................... 23
3.4.5. Modulation Shaping ............................................................................................................................... 23
3.4.6. RF Power Amplifiers .............................................................................................................................. 23
3.5. Receiver Description .........................................................................................................................................24
3.5.1. Overview ................................................................................................................................................ 24
3.5.2. LNA1, LNA2 ........................................................................................................................................... 24
3.5.3. Automatic Gain Control - AGC ............................................................................................................... 24
3.5.4. RSSI ........................................................................................................................................................26
3.5.5. Channel Filter......................................................................................................................................... 26
3.5.6. FSK Demodulator................................................................................................................................... 27
3.5.7. OOK Demodulator.................................................................................................................................. 27
3.5.8. Bit Synchronizer ......................................................................................................................................30
3.5.9. Frequency Error Indicator ...................................................................................................................... 30
3.5.10. AFC ........................................................................................................................................................ 31
3.5.11. Preamble Detector ................................................................................................................................. 32
SX1238 Rev.2, June 2014
©2014 Semtech Corp.
Page 2
www.semtech.com
|