TSA5059AT 데이터 시트보기 (PDF) - Philips Electronics

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TSA5059AT

2.7 GHz I2C-bus controlled low phase noise frequency synthesizer

Philips Electronics 

Philips Semiconductors

2.7 GHz I2C-bus controlled low phase

noise frequency synthesizer

Product specification

TSA5059A

APPLICATION INFORMATION

An example of a typical application is given in Fig.4. In this application the VCO centre frequency is 1.5 GHz with a slope

of 100 MHz/V. The expected loop bandwidth is 10 kHz with a charge pump current of 555 µA and fcomp of 250 kHz. Filter

components need to be adapted to each application depending on the VCO characteristics and the required performance

of the loop.

handbook, full pagewidth

47 nF

33 V

5V

3.9 kΩ

2.2 nF

27 kΩ

2.7 kΩ

1 nF

tuning

voltage

4 MHz 18 pF

CP

1

XTAL

2

DRIVE

16

15 GND

XT/COMP 3

14 RFB

AS 4

RFA

13

SDA

TSA5059A

5

12

VCC

SCL

6

ADC

11

MICRO-

CONTROLLER

P3 7

P2 8

10 P0

9 P1

BC847

1 nF

VCO

output

1 nF

10 nF

VCO

FCE714

Fig.4 Typical application.

Loop bandwidth

Most of the applications the TSA5059A 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 TSA5059A 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.

It is however possible to use a crystal with an higher

frequency (up to 16 MHz) to improve the noise

performance. When choosing a crystal, one should take

notice to select a crystal able to withstand the drive level of

the TSA5059A 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 TSA5059A, when

more than one synthesizer is present in the same

application. Then the application given in Fig.5 should be

used.

If the signal at pin XT/COMP is not used in an application

the output should be switched off (XCE = 0 and XCS = 0).

This pin should then be left open.

2000 Oct 24

15

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