W7020 Datasheet, PDF (4/36 Pages) List of Unclassifed Manufacturers – Bluetooth Radio Module

W7020 Bluetooth Radio Module
Preliminary Data Sheet
September 2000
Description (continued)
As shown in Figure 3, the antenna filter bandpass filters the radio signal to the antenna switch. The switch directs
the signal to the RX balun or from the TX balun. The RX balun performs the transformation from unbalanced to
balanced for the RX signal and connects to the low-noise amplifier (LNA). The LNA is followed by an image
rejection mixer, so no additional image filter is needed before the mixer. The IF signal out of the mixer is filtered
by a bandpass filter and followed by a limiting amplifier and frequency discriminator, giving the RX data output.
This discriminator output is offset-corrected. The receiver IF and detection circuits are all integrated, requiring no
external components. The RSSI level is available digitally through the serial interface.
The transmitter path utilizes direct modulation of the TX data-bit stream onto the VCO. The TX data is shaped by
the Gaussian filter and then is applied to the VCO tank. The VCO is buffered internally and driven to the TX
balanced output through another amplifier stage. The TX balun performs the transformation of the balanced to
unbalanced signal and connects to the antenna switch.
The VCO frequency operating in the 2.4 GHz ISM band is controlled by the phase-locked loop (PLL) synthesizer
through the loop filter. The reference clock oscillator is provided so that only a crystal resonator needs to be
added externally to the module, or the reference clock input can be overdriven with an external signal such as
from a TCXO or VCXO. The frequency accuracy requirement is ±20 ppm.
11 10
9
8
7
6
5
4
3
2
1
NC 12
GND 13
GND 14
GND 15
GND 16
ANT 17
SWITCH
RX
BALUN
TX
BALUN
LOOP VCO
FILTER TANK
ANTENNA
FILTER
XO
LNA
∑ BPF DISC
TX
AMP
Φ
LO
PLL
GLPF
34 SYS_CLK
33 SYS_CLK_REQ
32 PX_ON
31 LPO_CLK
30 POR
29 SI_CDO
18 19 20 21 22 23 24 25 26 27 28
Figure 3. Module Block Diagram with Pinout
4
Lucent Technologies Inc.