DEMOBOARD-U3600BM Atmel, DEMOBOARD-U3600BM Datasheet - Page 29

• Manufacturer Part Number: DEMOBOARD-U3600BM
• Description: BOARD DEMO FOR U3600BM
• Manufacturer: Atmel
• Type: Cordless Phone ICr

Specifications of DEMOBOARD-U3600BM

• Contents: Board, Software and Documentation
• For Use With/related Products: U3600BM
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

In our prototpye we used air-coils
with three windings and a diameter
of about 0.7 mm. The air-coils are
in resonance with the transmit frequency.
Due to the priciple of our transmitter stage, which is adjustment free, we have a certain amount
of noise. If the frequency distance from transmit to receive is large, then the noise causes no reduction
of receive sensitivity (e.g. in France, where the frequency distance is about 15 MHz); if the frequency
distance from transmit to receive is quite close then transmitter noise can be in the receive
region and can cause a sensitivity reduction (e.g. in China where transmit receive distance is just 3 MHz).
With the help of two tank circuits, one in the base of the transmit stage and one in the collector of
the transmit stage, we can eliminate most of the noise and in this way we can improve sensitivity.
With the help ot the above circuitry we get -114.5 dBm sensitivity with 12 dB SINAD with 17 mW output power.
As can be seen on our prototype, it is important to locate the transmit stage as close as possible to
the three transmit-stage pins-2/3/4.
RFOGND
CTR3
10nF
3WDG
2.7mm
2N3904
LT1
100pF
RFOGND
CT4
CT3
560pF
100nF 470nF
CTR2
RTR1 CT2
8.2k
3WDG
2.7mm
LT2
10nF
CRFO1
CT1
560pF
CVBATB2
VBAT
RFOGND
RFOVB
100nF
RFO
4
3
2
AGNDA
5
CGREF1
10nF
6
VBIAS
VCO2
7
VBATB
CVBATB1
470nF
12
AGNDA