SLIM-PDM rev C
Phase Detector Module
10-21-08: Update to
reflect SLIM-PDM Revision B
2-9-09: Update to add Schematic
8-11-09: Update to explain
voltage source option
. Add revision history.
11-20-10: Update to
reflect SLIM-PDM Revision C, addition of 2 capacitors.
11-25-11: Add links to Archived
5-16-15: Change capacitors.
Change Parts List to Rev D and move to this page.
1-20-16: Update to reflect new
printed wiring board, PWB-PDM Rev C. (note: there was no Rev B)
Phase Detector Module, size-A
Use your mouse's "right click" and "Save Link" to download:
Schematic, in ExpressPCB software.
Parts Layout. For parts locations.
PLSLIM-PDM Rev D. Parts List. Maintained on this page, only.
d. PWB-PDM rev C
PWB Artwork, in ExpressPCB software. Use to order from Express.
This SLIM-PDM is constructed on a common printed wiring
board, the PWB-PDM (rev C). Previously,
a separate web page for the PWB. I have deleted that page and
combined the information on this page. If you have constructed
the SLIM-PDM rev A, using the PWB-PDM (rev 0)
board, and would like to improve the PDM accuracy, see the
Modification Procedure on the end of this page.
The SLIM-PDM is a 360 degree, Phase to
Converter. It is specifically designed to operate at 10.7 MHz,
but will operate in the KHz range up to 30 MHz.
The J1 and J2 inputs can be sine or square wave . The min / max
is -20 dBm to +18 dBm. The min / max square input
is 10 mvpp to 5vpp.
Input impedance is nominally 50 ohms, but can be changed to any input
The output, at J3, is a DC voltage that is
the differential phase of the input signals at J1 and J2. The 0v
to +5v output should be loaded with 100 K or higher. A realistic
measurable phase range is from 20 degrees to 340 degrees with error
less than .1
Power requirements for the SLIM-PDM is
+7 volts to +15 volts at 50 ma.
Option when using PDM in MSA/VNA
The PDM has a provision to source +5 volts to a
separate Analog to Digital Converter module, the SLIM-ADC. This
allows both modules to use the same regulated +5volts. This
allows for more accurate Phase measurements. The SLIM-PDM
Rev 0 requires no change or modification for this application.
Later revisions require the placement of FBx.
Engineering Change Notice,
Although rare, the PDM rev B may have a tendency to
oscillate". A modification is made to prevent this rare instability.
If your PDM rev B is operating
normally you may omit the
modification. To modify and update SLIM-PDM-revB into SLIM-PDM-revC,
the addition of two capacitors is necessary (C24 and C25). See
Rev C. Also see LAYSLIM-PDM-Rev C.
When building a new SLIM-PDM rev C using the PWB-PDM Rev A, the
capacitors do not have pwb pads and
should be placed according to the layout (see below). Adding the jumper
wire to U9-6 (or U9-3) is difficult since the IC is so small. I would
suggest the PDM be built and tested in its final configuration before
this modification is performed. It may not even be necessary.
This ECN is incorporated on the PWB-PDM
Rev C. (see below)
Layout and parts
locator for SLIM-PDM
The document "layslim_pdm.gif" is used to locate
parts on the
board. To order PWB from Express, use pwb-pdm.pcb
Note: The layout and schematic show that there are
two ferrite beads supplying
U5, FBx and FB2. The installation of these beads is determined by
how the SLIM-PDM is used in a final configuration of a high level
SKSLIM-PDM, Schematic of