Differences

This shows you the differences between two versions of the page.

--- philpem:philips:sa572n [2023/12/21 00:58] – [Package] philpem
+++ philpem:philips:sa572n [2023/12/21 01:08] (current) – [Die] philpem
@@ Line 25: / Line 25: @@
 Later parts carry the more recent (~2000) Philips line-3 topmark format of ''YYWWDAR'' -- Year, Week, Diffusion, Assembly, (centre of) Responsibility. These later parts usually indicate "centre of responsibility" being Sunnyvale, i.e. Signetics. This matches up with the Philips datasheet indicating that this is a Signetics part.
-{{:philpem:philips:sa572n:pack_btm.jpg?300|}}
-<code>
-</code>
+====== Decap ======
+Decap took three attempts.
+  * First: rosin decap left residue stuck to the die surface.
+  * Second: Blowtorch caused thermal damage to the die.
+  * Third: rosin decap with hotter boil successfully decapped the chip.
 ====== Die ======
@@ Line 41: / Line 45: @@
   * [[https://siliconpr0n.org/map/philips/sa572n/single/philips_sa572n_philpem_bf20x_r.jpg|Single]] (25376x21760, 97.3794MiB)
+====== Circuit analysis notes ======
+  * The circuit is mirrored roughly down the centre.
+  * A 2.5V bandgap voltage reference is shared by both channels. This is likely the non-quite-symmetrical centre section.
+  * Bipolar process with extensive use of polysilicon resistors
+The [[https://www.onsemi.com/pdf/datasheet/sa571-d.pdf|SA571]] is a mono version of this chip. A SPICE model is available from [[https://modwiggler.com/forum/viewtopic.php?t=208611|jorg on the Mod Wiggler forums]], including a transistor-level schematic. This may make it easier to follow the circuitry on the IC.