CC2500 Datasheet, PDF (49/76 Pages) Texas Instruments – Single Chip Low Cost Low Power RF Transceiver

CC2500
transmitted in the same bandwidth using
GFSK.
30.7 Low Cost Systems
As the CC2500 provides 500 kbps multi-
channel performance without any external
filters, a very low cost system can be made.
A differential antenna will eliminate the need
for a balun, and the DC biasing can be
achieved in the antenna topology, see Figure
3.
A HC-49 type SMD crystal is used in the
CC2500EM reference design. Note that the
crystal package strongly influences the price.
In a size constrained PCB design a smaller,
but more expensive, crystal may be used.
Antenna
30.8 Battery Operated Systems
In low power applications, the SLEEP state
with the crystal oscillator core switched off
should be used when the CC2500 is not active.
It is possible to leave the crystal oscillator core
running in the SLEEP state if start-up time is
critical.
The WOR functionality should be used in low
power applications.
30.9 Increasing Output Power
In some applications it may be necessary to
extend the link range. Adding an external
power amplifier is the most effective way of
doing this.
The power amplifier should be inserted
between the antenna and the balun, and two
T/R switches are needed to disconnect the PA
in RX mode. See Figure 23.
Filter
PA
Balun
CC2500
T/R switch
T/R switch
Figure 23. Block diagram of CC2500 usage with external power amplifier
31 Configuration Registers
The configuration of CC2500 is done by
programming 8-bit registers. The configuration
data based on selected system parameters
are most easily found by using the SmartRF^®
Studio software. Complete descriptions of the
registers are given in the following tables. After
chip reset, all the registers have default values
as shown in the tables.
There are 14 Command Strobe Registers,
listed in Table 34. Accessing these registers
will initiate the change of an internal state or
mode. There are 47 normal 8-bit Configuration
Registers, listed in Table 35. Many of these
registers are for test purposes only, and need
not be written for normal operation of CC2500.
There are also 12 Status registers, which are
listed in Table 36. These registers, which are
read-only, contain information about the status
of CC2500.
The two FIFOs are accessed through one 8-bit
register. Write operations write to the TX FIFO,
while read operations read from the RX FIFO.
During the address transfer and while writing
to a register or the TX FIFO, a status byte is
Preliminary Data Sheet (rev.1.1.) SWRS040
Page 49 of 77