SI4112-EVB Silicon Laboratories Inc, SI4112-EVB Datasheet - Page 6

• Manufacturer Part Number: SI4112-EVB
• Description: BOARD EVALUATION FOR SI4112
• Manufacturer: Silicon Laboratories Inc
• Type: Synthesizerr

Specifications of SI4112-EVB

• Contents: Board and CD-ROM
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: SI4112
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Si4133/33G-EVB
Controls
The various controls are described below.
Reference
Update Rate
The reference divider value sets the update rate of the
phase detector for a given reference frequency. This
value can be set by either using the R-Divider input, the
Reference input, or the Update Rate input. All of these
controls are linked to set the R Divider in the
synthesizer. Writing to any of these registers for RF1 or
RF2 will select the associated synthesizer at the
RFOUT output.
The R-Divider input directly sets the R Divider of the
synthesizer. Changes made to this value will then
change the update rate and the synthesized frequency.
The Reference input changes all R Dividers to values
such that the update rate and synthesized frequency
remain at approximately the same value for the entered
reference frequency. Note that this changes only the
R Divider not the actual reference frequency of the on-
board oscillator.
Changing the Update Rate input changes the R and
N Dividers to maintain the same synthesized frequency
for a given reference frequency.
Phase Detector
The phase detector value window sets the relative gain
of the phase detector. Refer to the appropriate
synthesizer data sheet for further information about
setting of the phase detector gain.
The Auto K
for phase noise, settling time, and loop stability.
VCO and N Divider
The N Divider can be set by an integer in the N-Divider
register or by a decimal frequency in the VCO window.
Writing to either of these registers for RF1 or RF2 will
select the associated synthesizer at the JRF1
connector. The N-Divider window writes directly to the
N Divider of the synthesizer.
The values entered in the VCO register will cause the
software to automatically compute and set the N
register to generate the specified frequency.
RF Select
The RF Select toggle switch selects the RF1 or RF2
synthesizer output on the JRF1 connector. This control
does not correspond to an actual control bit.
Synthesizers are toggled by writing to the N Divider of
the selected synthesizer. User applications should
select the active synthesizer by writing to the N or R
register as outlined in the appropriate synthesizer data
sheet.
6
P
Divider,
option will automatically select the best K
Reference
Frequency,
Preliminary Rev. 0.5
and
P
Auxiliary Output Control
Auxiliary Output Control selects the function of the
AUXOUT pin. This pin can be used to monitor various
functions internal to the synthesizer. Refer to the
appropriate synthesizer data sheet for details.
This pin also performs the serial read function of the
synthesizer registers by the PC. Serial data will appear
at this pin if “Verify Device Writes” or if the VCO Tuning
Meters are enabled in the SiLabs pull-down menu.
Power Down Control
The Power Down Control radio buttons select the
various software power-down options of the frequency
synthesizer IC. (See Figure 2.) The label for each radio
button corresponds to the name of the control bit being
programmed. See the appropriate synthesizer data
sheet for a complete description of power control
options.
AUTOPDB, Force All On, forces the reference amplifier,
the RF synthesizers, and the IF synthesizer on. These
synthesizers can be enabled independently of each
other using PDIB and PDRB.
The hardware PWDNB input overrides all power-up
settings selected in this window. The serial interface
remains active when powered down.
Menus and Options
Menus and options are described below.
File Menu
The File menu allows register configurations to be
saved and restored. By default, configurations are
stored as .cfg files in the Configurations folder within the
Si4133 Programmer folder. (See Figure 3.)
Figure 2. Power-Down Control Radio Buttons