{{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 ======

{{:philpem:philips:sa572n:pack_top.jpg?300|}}

<code>
TL  [Philips]  SA572N
HA  [Logo]     GGW1791
AN             9814nH
ID
</code>

Topmark decodes as (per 2000 Philips Quality Manual, repeated at https://www.dutchaudioclassics.nl/TDA1541-Product-manufacturing-codes-and-markings/):

  * Commercial part number: SA572N  (SA572, 16-pin dual in-line package)
  * 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 ======

<code>
</code>

{{https://siliconpr0n.org/map/philips/sa572n/single/philips_sa572n_philpem_bf20x_r.thumb.jpg}}

[[https://siliconpr0n.org/map/philips/sa572n/philpem_bf20x_r/|Brightfield, Olympus MSplan 20x]]

  * [[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.