TSA5060AT PHILIPS [NXP Semiconductors], TSA5060AT Datasheet - Page 15

• Manufacturer Part Number: TSA5060AT
• Description: 1.3 GHz I2C-bus controlled low phase noise frequency synthesizer
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
APPLICATION INFORMATION
An example of a typical application is given in Fig.4. In this application the VCO centre frequency is 600 MHz with a slope
of 18 MHz/V. The expected loop bandwidth is 13 kHz with a charge pump current of 1230 A and a comparison
frequency of 166.67 kHz. Filter components need to be adapted to each application depending on the VCO
characteristics and the required performance of the loop.
Loop bandwidth
Most of the applications that the TSA5060A are dedicated
for require a large loop bandwidth, in the order of a
few kHz to a few tens of kHz. The calculation of the loop
filter elements has to be done for each application, while it
depends on the VCO slope and phase noise, as well as the
reference frequency and charge pump current.
A simulation of the loop can easily be done by using the
SIMPATA software from Philips.
Reference source
The TSA5060A is well suited to be used with a 4 MHz
crystal connected to pin XTAL. Philips crystal ordering
code 4322 143 04093 is recommended in this case.
2000 Oct 24
handbook, full pagewidth
1.3 GHz I
noise frequency synthesizer
2
C-bus controlled low phase
CONTROLLER
4 MHz
MICRO-
18 pF
XT/COMP
XTAL
SDA
SCL
CP
AS
P3
P2
47 nF
1
2
3
4
5
6
7
8
TSA5060A
Fig.4 Typical application.
180 pF
10 k
16
15
14
13
12
11
10
33 V
9
5 V
15
V CC
DRIVE
GND
RFB
RFA
ADC
P0
P1
It is however possible to use a crystal with a higher
frequency (up to 16 MHz) to improve the noise
performance. When choosing a crystal, care should be
taken to select a crystal able to withstand the drive level of
the TSA5060A without suffering from accelerated ageing.
It is also possible to feed pin XTAL with an external signal
between 2 and 20 MHz, coming from an external oscillator
or from the pin XT/COMP of another TSA5060A, when
more than one synthesizer is present in the same
application. The application given in Fig.5 should then be
used.
If the signal at pin XT/COMP is not used in an application,
the output should be switched off (bits XCE = 0, XCS = 0).
This pin should then be left open.
27 k
BC847
10 nF
1 k
1.8 nF
1 nF
1 nF
output
VCO
voltage
tuning
VCO
FCE719
Product specification
TSA5060A