CC400 Chipcon, CC400 Datasheet - Page 6

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

Circuit Description
A simplified block diagram of
shown in figure 1. Only signal pins are
shown.
In receive mode
traditional heterodyne receiver. The RF
input signal is amplified by the low-noise
amplifier (LNA) and converted down to the
intermediate frequency (IF) by the mixer
(MIXER). In the intermediate frequency
stage (IF STAGE) this downconverted
signal is amplified and filtered before
being fed to the demodulator (DEMOD).
As an option an external IF filter can be
used for improved performance. After
demodulation
digital demodulated data on the pin DIO.
Synchronisation and final qualification of
the demodulated data is done by the
interfacing digital system (microcontroller).
In transmit mode the voltage controlled
oscillator (VCO) output signal is fed
Chipcon AS
RF_OUT
RF_IN
CC400
CC400
LNA
Figure 1. Simplified block diagram of the
SmartRF
PA
outputs the raw
is configured as a
MIXER
VCO
TM
CC400
VCO_IN
~
CC400
CHP_OUT
IF_OUT IF_IN
is
Freq. divider
CHARGE
PUMP
Datasheet (rev. 3.1) 2003-11-12
/N
IF STAGE
SmartRF
directly to the power amplifier (PA). The
RF output is frequency shift keyed (FSK)
by the digital bit stream fed to the pin DIO.
The internal T/R switch circuitry makes the
antenna interface and matching very easy.
The frequency synthesiser generates the
local oscillator signal which is fed to the
MIXER in receive mode and to PA in
transmit mode. The frequency synthesiser
consists of a crystal oscillator (XOSC),
phase
(CHARGE PUMP), VCO, and frequency
dividers (/R and /N). An external crystal
must be connected to XOSC, and an
external LC-tank with a varactor diode is
required for the VCO. For flexibility the
loop filter is external.
For chip configuration
wire digital serial interface (CONTROL).
PD
detector
DEMOD
/R
CONTROL
CC400
OSC
(PD),
.
®
CC400
3
CLOCK, PDATA, STROBE
DIO
LOCK
XOSC_Q2
XOSC_Q1
CC400
charge
includes a 3-
Page 6 of 27
pump