Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510) 668-7000 • FAX (510) 668-7017 • www.exar.com
XR18W753
SINGLE CHIP 868MHZ TO 956MHZ RF TRANSCEIVER
MARCH 2008 REV. 1.0.0
GENERAL DESCRIPTION
The XR18W753 is a low-power, single-chip RF
transceiver designed to operate in license-free
European 868 MHz SRD, North American / Australian
915 MHz ISM bands. Digital I/Q modulation,
demodulation and direct sequence spread spectrum
techniques were employed to provide robust data
transmission in signal congested RF environments.
The device provides extensive hardware support for
packet handling such as frame timing, data buffering,
RSSI/ED/LQI for clear channel assessment, and FCS
and CRC hardware for error detection. TX output
power is programmable from -24 dBm to 0 dBm with
100 Kbps and 250 Kbps O-QPSK data supported.
APPLICATIONS
• Industrial/Home automation, monitoring and control
• Point of sales and data collection terminals
• Entertainment, game, toy, robot, and remote control
• Active RFID, asset tracking and keyless entry
• Lighting, HVAC energy management
• Automatic meter reading
• Wireless sensor and telemetry networks
FEATURES
• 2.2 to 3.6 Volt Operation
• 868 MHz to 956 MHz
• Direct-Sequence-Spread-Spectrum Transceiver
• Direct-up-conversion I/Q modulator
• Low-IF I/Q digital receiver
• Superior blocking/desensitization performance
• RSSI / ED / LQI for clear channel assessment
• FCS computation and CRC for error detection
• Low BOM cost and ease of production
• I
2
C Interface to data buffer and internal registers
• Fully integrated loop filter with few external
components needed (crystal, capacitors, antenna
and matching networks)
• Programmable TX output power in 3 dB steps
• Receiver sensitivity of -94 dBm at 100 Kbps
• Supports O-QPSK 100 Kbps and 250 Kbps data
• Industrial temperature (-40 to +85
o
C)
• 48-pin QFN package
FIGURE 1. RF TRANSCEIVER BLOCK DIAGRAM
DAT A
ACCESS
CONTROLLER
TX
DAT A
BUFFER
RX
DAT A
BUFFER
Modem Cont rol & Stat us
P
L
M
E
Modem
Cont r ol l er
CRC
Di g i t al
Modem
RF
CL OCK
GENERATI ON
Vo l t a g e
Re g u l a t or
16MHz
CL K
VREG_CLK_EN
SCL
SDA
Mat chi ng
Ne t wo r k
IRQ#
cca_ed_r eady
pck_t x_r eady
pck_r ecei ved
pl me_r eady
16MHz
XT AL
DAT A
ACCESS
CONTROLLER
TX
DAT A
BUFFER
RX
DAT A
BUFFER
Modem Cont rol & St at us
P
L
M
E
Modem
Cont r ol l er
CRC
Di g i t al
Modem
RF
CL OCK
GENERATI ON
Vo l t a g e
Re g u l a t or
16MHz
CL K
VREG_CLK_EN
SCL
SDA
Mat chi ng
Ne t wo r k
IRQ#
cca_ed_r eady
pck_t x_r eady
pck_r ecei ved
pl me_r eady
16MHz
XT AL
