Gregory's ServerTo make a capacitor, each PZT cube has a platinum plate line underneath and a platinum plate contact on top. The plate lines are the shiny vertical white rectangles in this photo. At the bottom, large transistors drive the selected plate line positive or negative.
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6 comments
 To learn more about this FRAM chip, see my blog post: https://www.righto.com/2024/09/ramtron-ferroelectric-fram-die.html  @bitsavers There are multiple factors that limit the number of writes that FRAMs can handle: changes in crystal structure as Ti ions replace O, mobile ions collecting at grain boundaries, and something to do with 90º domains.  @kenshirriff @bitsavers it's not really infinite since the endurance was probably reached in Marc's DRO. The fram was used by the readout to give the illusion of an absolute scale, but I believe the integrated fram that failed was updated too often (maybe every scale tick).  |
Here's a closeup of the part number and Ramtron logo on the die.