TSA5059 Ver la hoja de datos (PDF) - Philips Electronics
Número de pieza
componentes Descripción
Fabricante
TSA5059 Datasheet PDF : 24 Pages
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Philips Semiconductors
2.7 GHz I2C-bus controlled low phase
noise frequency synthesizer
Preliminary specification
TSA5059
handbook, full pagewidth
4 MHz
18 pF
1
16
2
15
3
14
4
13
TSA5059
5
12
6
11
7
10
8
9
1.0 nF
1.2 kΩ
1
16
2
15
3
14
4
13
TSA5059
5
12
6
11
7
10
8
9
FCE124
Fig.5 Application for using one crystal with two TSA5059s.
I2C-bus crosstalk and loop amplifier
The TSA5059 includes a loop amplifier between pin CP
and pin VT. While this amplifier shares the same ground
pin as the I2C-bus, there may be some I2C-bus crosstalk.
The best way to avoid any I2C-bus crosstalk, both in the
PLL IC and in the application (i.e. parasitic coupling
between the I2C-bus lines and the VCO coil), is to avoid
the I2C-bus signal to come in the RF part by using an
I2C-bus gate that allows only the messages for the PLL to
go to the PLL, and to avoid unnecessary repeated
sending. Such a gate is integrated in most of the Philips
digital demodulators.
If I2C-bus crosstalk is still a problem, it is possible not to
use the internal amplifier, and to replace it with a NMOS
transistor in the application as given in Fig.6. In this case
the pin VT is left open, and it is possible to implement on
the PCB the foot print for a jumper between the tuning
voltage line and pin VT to be able to choose either the
internal amplifier (mounting the jumper and not the NMOS
transistor) or the external amplifier (mounting the NMOS
transistor and not the jumper). It is recommended to use a
BSH111 or BSH121 N-channel MOS transistor. The
threshold voltage of the transistor has to be lower than
2.0 V.
1999 Oct 05
16
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