CC400 Chipcon, CC400 Datasheet - Page 17

• Manufacturer Part Number: CC400
• Description: Single Chip High Performance RF Reansceiver
• Manufacturer: Chipcon

System Considerations and Guidelines
Low cost systems
In systems where low cost is of great
importance the 200 kHz IF should be
used. The oscillator crystal can then be a
low cost crystal with 50 ppm frequency
tolerance.
Battery operated systems
In low power applications the power down
mode should be used when not being
active. Depending on the start-up time
requirement, the oscillator core can be
powered during power down. Precharging
of the demodulator may also be used to
reduce the receiver turn-on time, see
description p.18.
Narrow band systems
CC400
band systems. However, it is then required
to use a crystal with low temperature drift
and ageing. A trimmer capacitor in the
crystal oscillator circuit (in parallel with
C151) may also be necessary to set the
initial frequency.
Chipcon AS
is also suitable for use in narrow
SmartRF
TM
CC400
Datasheet (rev. 3.1) 2003-11-12
SmartRF
It is also possible to include an external IF-
filter at 455 kHz. This should be a ceramic
filter with 1.5 kΩ input/output impedance
connected between IF_OUT and IF_IN.
Typical bandwidth is 30 kHz. Due to the
high Q of such a filter, a better selectivity
can be achieved. See Application Note
AN005 “Selecting system parameters and
system configurations using CC400 /
CC900” for more details.
High reliability systems
Using a SAW filter as a preselector will
improve the communication reliability in
harsh environments by reducing the
probability of blocking.
Spread spectrum frequency hopping
systems
Due to the very fast frequency shift
properties of the PLL, the
well be used in frequency hopping
systems.
®
CC400
CC400
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