SLIM-MXR-3 rev A
Mixer
Updated 6-13-08.  Updated to reflect Revision A
SLIM-MXR-3, Mixer, size-A
Use your mouse's "right click" and "Save Link" to download:
a. 
SKSLIM-MXR-3 rev A , Schematic, in ExpressPCB software.
b.  LAYSLIM-MXR-3 rev A, Layout, in ExpressPCB software.  Use this drawing to locate the parts on the SLIM Board.
c.  PLSLIM-MXR-3 rev B, Parts List in text format.
d.  PWB-MXR-ADE, Base artwork for PWB, in ExpressPCB software.  Use this drawing to order the pwb from Express.
This SLIM is constructed on a common printed wiring board, the PWB-MXR-ADE.  Click to get full information on this Mixer PWB.

    The SLIM-MXR-3 is configured with the Minicircuits, ADE-11X.  This mixer was originally designed to be used as the mixer addition when adding the Tracking Generator to the MSA.  Minicircuits specify the conversion loss at -7.5 dB.  I measured the conversion loss at -6.5 dB.  I continue to recommend this mixer, only because of it's very low cost.

Revision A:
1. 
Added a 2.5 dB attenuator network in the L port path to the mixer.  This provides a better impedance match between the LO input connector -  J1, and the mixer, which, improves the mixer isolation.
2.  Added a 14 dB attenuator network in the R port path to the mixer.  This provides a better impedance match between the R input connector -  J31, and the mixer.
3.  Added a 2 pF chip capacitor to the mixer pin 3 junction to ground (C29 position).  This helps match the mixer to the 14 dB attenuator network and J3.
These modifications greatly improve the mixer isolation.  This makes it necessary for the LO Drive to be approximately +10 dBm.  To use this module as a mid-drive (+7dBm), the attenuator must be removed.


SKSLIM-MXR-3, Schematic of SLIM-MXR-3
slim/skslim_mxr_3.gif
    The coupling resistor R15 is a short circuit (zero ohm resistor), allowing very low frequencies to pass.  C5 and C25 are low value capacitors to allow only high frequencies to pass.

LAYSLIM-MXR-3, Parts locator for SLIM-MXR-3
slim/layslim_mxr_3.gif  slim/mixer1.JPG
    The photo was taken before C29 and attenuators were added to the board.