Differences

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--- philpem:philips:sa572n [2023/12/20 23:49] – external edit 127.0.0.1
+++ philpem:philips:sa572n [2025/08/04 21:24] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
 {{tag>collection_philpem vendor_philips type_unknown year_unknown foundry_unknown}}
+SA572 stereo audio compander
+Datasheet: https://www.alldatasheet.com/datasheet-pdf/pdf/18876/PHILIPS/SA572.html or https://www.onsemi.com/pdf/datasheet/sa572-d.pdf
 ====== Package ======
@@ Line 7: / Line 11: @@
 <code>
+TL  [Philips]  SA572N
+HA  [Logo]     GGW1791
+AN             9814nH
+ID
 </code>
-{{:philpem:philips:sa572n:pack_btm.jpg?300|}}
+Topmark decodes as (per 2000 Philips Quality Manual, repeated at https://www.dutchaudioclassics.nl/TDA1541-Product-manufacturing-codes-and-markings/):
-<code>
+  * Commercial part number: SA572N  (SA572, 16-pin dual in-line package)
-</code>
+  * Diffusion lot GGW17, assembly sequence 91
+  * Date of manufacture 1998, week 14. Diffused at Philips Semiconductors Nijmegen (H), assembled in Bangkok (n)
+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.
+====== 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 20: / Line 40: @@
 </code>
-{{https://siliconpr0n.org/map/philips/sa572n/single/philips_sa572n_philpem_bf20x_r.thumb.jpg}}
+{{https://siliconprawn.org/map/philips/sa572n/single/philips_sa572n_philpem_bf20x_r.thumb.jpg}}
+[[https://siliconprawn.org/map/philips/sa572n/philpem_bf20x_r/|Brightfield, Olympus MSplan 20x]]
+  * [[https://siliconprawn.org/map/philips/sa572n/single/philips_sa572n_philpem_bf20x_r.jpg|Single]] (25376x21760, 97.3794MiB)
+====== Circuit analysis notes ======
-[[https://siliconpr0n.org/map/philips/sa572n/philpem_bf20x_r/|bf20x_r]]
+  * 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
-  * [[https://siliconpr0n.org/map/philips/sa572n/single/philips_sa572n_philpem_bf20x_r.jpg|Single]] (25376x21760, 97.3794MiB)
+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.