ST AN2452 Application note

AN2452

Application note

STW8110x evaluation board and graphical user interface

Application and scope

This application note describes the evaluation board (EVB) and the graphical user interface (GUI) of the STW81101, STW81102 and STW81103 multi-band RF frequency synthesizers (with integrated VCOs).

The STW8110x GUI software allows the STW81101, STW81102 and STW81103 synthesizers to be programmed via an I

Three evaluation boards are available depending on the output matching network optimal frequency range:

■ EVB1G (single output - 1 GHz - output divider by 4)

■ EVB2G (single output - 2 GHz - output divider by 2)

■ EVB4G (single output - 4 GHz - direct output)

C/SPI control interface.

February 2008 Rev 3 1/21

www.st.com

Contents AN2452

Contents

1 Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.1 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2 Main form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.3 Tutorial operation mode form . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.4 Waveform viewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2 Evaluation board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.1 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.2 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.2.1 Top view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

2.2.2 Bottom view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.3 Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2.4 Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2.5 Bill of materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

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1 Software

1.1 Installation

The STW8110x GUI software is built on the Microsoft (R) .NET Framework (see

http://www.microsoft.com/net/default.mspx

(R) .NET Framework version 2.0, which may require the installation of Windows Installer 3.0 (see

http://msdn.microsoft.com/library/default.asp?url=/library/en-

us/msi/setup/windows_installer_start_page.asp

install Microsoft (R) .NET Framework and Windows Installer.

Follow these steps to install the STW8110x GUI:

1. If an old version of the GUI is already installed, uninstall it.

2. Run

setup.exe

(datasheets, programming configuration files and desktop/quick launch

shortcuts are optional components installed by default).

3. Run

STW8110xGUI.exe

4. The default starting operation mode is Tutorial. The starting operation mode can be modified by means of the radio buttons in the tutorial form:

a) Tutorial: a brief tutorial on the features of the GUI.

b) Basic: only the main options are enabled.

c) Advanced: all the available options are enabled.

). It may require the installation of the Microsoft

). Administrator privileges are required to

1.2 Main form

This section details the items on the main form. See

1. Pressing this button shows the About STW8110xGUI screen.

2. Pressing this button opens the datasheet of the selected device.

3. Help

4. Device selection (STW81101/2/3).

5. GUI operation modes:

Tutorial: A brief tutorial on the basic features of the GUI. An inner default configuration is loaded.

Basic: only the main options are enabled. Frequency values must be set in the following order:

a) Input reference frequency F

b) Output frequency step F

c) Output frequency F

The calibrator is always ON. VCO and output divider are set automatically.

Advanced: all the available options are enabled. Any F message will warn if the inserted values are beyond the frequency limits of the VCOs. Frequency values must be set in the following order:

a) Input reference frequency F

b) Output frequency step F

c) Output frequency F

Waveform Viewer: a form is opened displaying the bit sequence sent to the device.

out

step

or F

ref

or F

vco

Figure 1: Main form

on page 4.

vco

or F

are allowed. A

out

pfd

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Software AN2452

Figure 1. Main form

6. Swallow counter A: 5-bit counter.

7. VCO calibrator:

– Last calibration F

: contains the last calibration data (VCO and frequency of

vco

calibration).

– Calibrator ON/OFF.

– The maximum allowed F

pfd

is programmed in two steps:

a) Device is programmed forcing calibration with the maximum F

= F

pfd

/ R ≤ 1 MHz ==> R ≥ F

ref

b) Device is programmed with the desired F

Example with F

= 76.8 MHz:

ref

Desired values:

- F

= 1200 kHz

pfd

- R = F

ref

/ F

pfd

= 64

Forced values:

- R' = ⎡F

- F'

pfd

/ 106⎤ = ⎡76.8⎤ = 77

ref

= F

/ R' = 997.403 kHz

ref

Device programming in two steps:

a) Device is programmed with F

b) Device is programmed with F

during calibration is 1 MHz. If F

/ 106).

ref

pfd

= 997.403 kHz and Calibrator ON.

pfd

= 1200 kHz and Calibrator OFF.

pfd

> 1 MHz, the device

pfd

≤ 1MHz

pfd

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8. Output divider:

– Direct output.

– Divider by 2.

– Divider by 4.

9. Configurations:

– Load/Save: load/save a configuration file.

– Load default/Save default: load/save a default configuration.

10. Program counter B: 12-bit counter.

11. VCO. VCO settings:

– Output frequency range/VCOs frequency range: press this button to show

information on the limits of F

out/Fvco

(only for the embedded VCOs).

– VCO selection (enabled only in Advanced mode):

- EXT: external VCO. The external VCO buffer is able to manage a signal coming from an external VCO in order to build a synthesizer using the STW8110x only as PLL IC. The external VCO signal can range from 625 MHz up to 5 GHz. Its minimum power level must be -10 dBm.

- VCO A/VCO B: embedded VCOs.

12. Parallel port address. Hex value of the parallel port base address:

– 278: normally assigned to LPT2.

– 378: normally assigned to LPT1.

–3BC

– FILE: output is saved to a text file.

13. Prescaler modulus:

–P=16

–P=19

14. Reference divider. The 10-bit programmable reference counter allows the input reference frequency to be divided to produce the input clock to the phase frequency detector (PFD):

= F

ref

/ R

pfd

where

–F

: PFD input frequency

pfd

: input reference frequency

ref

Limits: 2 ≤ R ≤ 1023

15. Frequency settings:

–F

– -/+: finds a lower/higher rational value for F

–F

: input reference frequency (MHz)

ref

- Limits: 10 MHz ≤ F

: phase frequency detector (PFD) input frequency (kHz)

pfd

= F

pfd

vco

/ R, where R is the reference divider factor.

ref

: VCO oscillating frequency (MHz) = N · F

pfd

≤ 200 MHz

ref

pfd

– N: PLL division ratio

N = B

· P + A.

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Software AN2452

16. Output frequency settings:

–F

– -/+: finds a lower/higher rational value for F

: output frequency (MHz)

out

= F

/ DIV, where DIV is the output division ratio.

vco

: output frequency step (kHz)

= F

/ DIV, where DIV is the output division ratio.

pfd

out

step

17. Charge pump current. The nominal value of the output current is controlled by an external resistor (R

) and can be varied over 8 levels by means of 3 dedicated

ext

programming bits:

– CPSEL[2:0]: bits controlling the charge pump current

–R

–I

: the minimum value of the current is:

ext

= 2 Vbg / R

min

: charge pump current (mA)

= (CPSEL + 1) · I

where Vbg = 1.17 V.

ext

min

18. VCO voltage amplitude. The voltage swing of the VCOs can be adjusted over 4 levels by means of two dedicated programming bits:

– PLL_A[1:0]: bits controlling the voltage swing of the VCO.

This setting trades current consumption with the VCO’s phase noise performances. Higher amplitudes provide better phase noise, whereas lower amplitudes save power.

19. Two digital interfaces are available:

–I

- ACK: if checked and the acknowledge is not received, read and write operations fail. Uncheck this if the board is not enabled to read.

- Read: read the read-only register.

- Write: write the 6 write-only registers.

- A[2:0]: the device address (1100A

2A1A0

) must be set.

–SPI

Show sent data: the programming sequence is shown on the message list.

20. Device programming:

– Device programming modes:

- Device ON: device on with output buffer control disabled.

- Out Buffer CTRL: device on with output buffer control enabled. This control mode allows to enable/disable the output stage by a hardware control pin (EXT_PD, pin

23) while the PLL stays locked at the desired frequency; in such a way a very fast switching time is achieved. This feature can be useful in designing a ping-pong architecture saving the cost of an external RF switch.

- Power Down: 'Power Down' mode enabled (device off).

– SEND: press this button to program the device.

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21. Message list: displays information, warnings and errors:

– CLEAR: press this button to delete all the messages.

Clicking the right mouse button on the message list shows a menu:

– Copy: copy the selected messages to the clipboard.

– Copy to File: copy the selected messages to a file.

– Append Mode: file is opened in append mode when 'Copy to File' is used.

– Select All: all messages are selected (double-clicking the left mouse button has

the same effect).

– Deselect All: no message is selected.

– Clear after Send: clears the message list after pressing the Send button.

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