Texas Instruments CC2500 User Manual

CC2500
S
WRS040
C
Page
46
of
89
23
Voltage Regulators
CC2500
contains several on
-
chip linear voltage
regulators, which generate the supply voltage
needed by low
-
voltage modules. Th
ese
voltage regulators are invisible to the user, and
can be viewed as integral parts of the various
modules. The user must however make sure
that the absolute maximum ratings and
required pin voltages in
Table
1
a
nd
Table
13
are not exceeded. The voltage regulator for
the digital core requires one external
decoupling capacitor.
Setting the
CSn
pin low turns on the voltage
regulator to the digital core and starts the
crystal
oscillator. The
SO
pin on the SPI
interface must go low before
the first positive
edge of
SCLK
(setup time is given in
Table
16
).
If the chip is programmed to enter power
-
down
mode, (
SPWD
strobe issued), the powe
r will be
turned off after
CSn
goes high. The power and
crystal oscillator will be turned on again when
CSn
goes low.
The voltage regulator output should only be
used for driving the
CC2500
.
24
Output Power Programming
The RF output power level from the de
vice has
two levels of programmability, as illustrated in
Figure
21
.
The RF output power level from the device is
programmed through the
PATABLE
register.

If 2
-
FSK, GFSK or MSK modulation is
used the desired outpu
t power
is
programmed
to index 0 in the
PATABLE
register (
PATABLE
(0)
[
7:
0]
).
The 3
-
bit
FREND0.PA_POWER
value shall be set to 0
(reset default value).

If OOK modulation is
used
the desired
output power for the logic 0 and logic 1
power levels
are programmed
to index 0
and index 1 in the
PATABLE
register
respectively (
PATABLE
(0)
[
7:
0]
and
PATABLE
(1)
[
7:0
]
).
The 3
-
bit
FREND0.PA_POWER
value shall be set to
1.
Table
31
contains recommended
PATABLE
settings for various output levels and
frequency bands. See Section
10.6
on page
24
for
PATABLE
programming details.
The
SmartRF

Studio software
[5]
should be used
to obtain optimum
PATABLE
settings for
various output powers.
PATABLE
must be programmed in burst mode
if writing to other entries than
PATABLE
(0)
(OOK modulation). Note that all content of the
PATAB
LE
, except for the first byte (index 0) is
lost when entering the SLEEP state.

Texas Instruments CC2500 Specifications

General

Brand	Texas Instruments
Model	CC2500
Category	Transceiver
Language	English