XE1202A Ver la hoja de datos (PDF) - Semtech Corporation

Número de pieza

componentes Descripción

Fabricante

XE1202A

433 MHz / 868 MHz / 915 MHz Low-Power, Integrated UHF Transceiver

Semtech Corporation 

XE1202A TrueRF™

The schematic of the recommended matching network at the output of the transmitter is given in Figure 16 below.

The two Π-sections are used to provide harmonic filtering for passing FCC and ETSI regulations:

VDD

CT2

LT3

CT3

LT2

XE1202A

TrueRF™

...

Figure 16: Transmitter output network

The typical component values of this matching circuit are given Table 27 below:

Name

CT1

CT2

CT3

CT4

CT5

LT1

LT2

LT3

Typical Value

for 434 MHz

6.8 pF

1.0 pF

22 pF

6.8 pF

4.7 pF

33 nH

22 nH

22 nH

Typical Value

for 869 MHz

1.5 pF

0.56 pF

15 pF

3.3 pF

2.2 pF

39 nH

10 nH

8.2 nH

Typical Value

for 915 MHz

1.8 pF

NC

33 pF

3.3 pF

2.2 pF

47 nH

10 nH

8.2 nH

Table 27: Matching circuit component values

Tolerance

±5%

±5%

±5%

±5%

±5%

±5%

±5%

±5%

6.3 VCO tank

The tank of the VCO is implemented with an inductor in parallel with an (optional) capacitor. The recommended

values for these components are given in Table 28 below:

Name

LR1

CR1

434 MHz

39 nH ± 2 %

NC

869 MHz

6.8 nH ± 2 %

NC

915 MHz

5.6 nH ± 2 %

NC

Table 28: VCO tank component values

In order to optimize the tuning range of the VCO, the value of the inductance should be as high as possible and

external capacitance must be avoided if possible. It is recommended that the PCB layout includes two ‘footprints’ in

order to place two inductances in parallel; this enables the tank of the VCO to be centered more precisely.

© Semtech 2006

29

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