THS720: Difference between revisions

THS720 (view source)

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 The DMM is a 3¾-digit Maxim MAX134CQH.
-The analog scope section starts with an attenuator hybrid driven by four channels of
+The analog scope section starts with an attenuator hybrid driven by four channels of HP (now Broadcom/Avago) optoisolators and NEC relays.
-HP (now Broadcom/Avago) optoisolators and NEC relays.  The hybrid contains the AC coupling
+The hybrid contains the AC coupling capacitor and many laser trimmed resistors along with a custom Tek [[165-2545-00]] BGA.
-capacitor and many laser trimmed resistors along with a custom Tek [[165-2545-00]] BGA.
+The signal then passes through a single-ended to differential transformer and goes to a custom labeled Maxim two-channel high speed A/D converter [[234-1503-20]].
-The signal then passes through a single-ended to differential transformer and
+Note that the differential signal layout for channel 2 is not as good as channel 1 since one side of channel 2 goes through 2 vias not found on channel 1.
-goes to a custom labeled Maxim two-channel high speed A/D converter [[234-1503-20]].
-Note that the differential signal layout for channel 2 is not as good as channel 1
-since one side of channel 2 goes through 2 vias not found on channel 1.<br>
 These optoisolators sometimes drift, causing a DC offset issue. They can be directly replaced with Broadcom/Avago part number HCNR201 (any of the -300E, -500E, -350E, or -550E variants will work) which are still readily available.