CC2400 Chipcon AS, CC2400 Datasheet - Page 14

• Manufacturer Part Number: CC2400
• Description: 2.4 GHz RF Transceiver
• Manufacturer: Chipcon AS

Circuit Description
A simplified block diagram of
shown in Figure 2.
CC2400
received RF signal is amplified by the low-
noise amplifier (LNA) and down-converted
in quadrature (I and Q) to the intermediate
frequency (IF). At IF (1 MHz), the I/Q
signal is filtered and amplified, and then
digitized by the ADCs.
control,
demodulation and bit synchronization is
performed digitally.
CC2400
the digital demodulated data on the DIO
pin. A synchronized data clock is then
available at the DCLK pin. In buffered
mode the demodulated data is sent to a
FIFO and is accessible through the SPI
interface. RSSI is available in digital
format and can be read via the serial
interface. The RSSI also features a
programmable carrier sense indicator with
output on either GIO1 or GIO6.
Chipcon AS
On-chip
BIAS
CC2400
TX/RX CONTROL
LNA
SmartRF
outputs (in un-buffered mode only)
PA
features a low-IF receiver. The
16 MHz
XOSC
final
Control
Power
SmartRF
®
®
Σ
channel
CC2400 PRELIMINARY Datasheet (rev. 1.1), 2003-10-02
Figure 2.
Automatic gain
CC2400
filtering,
CC2400
0
is
90
simplified block diagram
SmartRF
In transmit mode the baseband signal is
directly up-converted quadrature (I and Q)
and then fed to the power amplifier (PA).
The TX IF signal is frequency shift keyed
(FSK). Optionally Gaussian filtering can be
used enabling GFSK. The BT of the
Gaussian filter is 0.5 for a datarate of
1 Mbps.
The internal T/R switch circuitry makes the
antenna interface and matching very easy.
The antenna connection is differential. The
biasing of the PA and LNA is done by
connecting RXTX_SWITCH to RF_P and
RF_N through an external DC path.
Optionally one output can be turned off,
giving a single ended output, but at a
reduced output power level and receiver
sensitivity.
The frequency synthesizer includes a
completely on-chip LC VCO and a 90
degrees phase splitter for generating the
TX POWER CONTROL
ADC
ADC
SYNTH
DAC
DAC
FREQ
AGC CONTROL
®
- Digital RSSI
- Gain Control
- Image Suppression
- Channel Filtering
- Demodulation
- Data Filtering
- Modulation
- Power Control
DEMODULATOR
MODULATOR
DIGITAL
DIGITAL
CC2400
INTERFACE /
DIGITAL
FIFO
Page 14 of 73