component

AMS1117-3.3

Public Made by Adom

by adom

AMS1117-3.3 — 1A low-dropout fixed 3.3V linear voltage regulator, SOT-223. Common 5V→3.3V rail LDO.

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Open general

Deprecate in favour of the AMS1117 family page (adom/ams1117)

barrett-land · 2mo ago

The new family page adom/ams1117 now covers the whole AMS1117 part family from the Advanced Monolithic Systems datasheet: all six fixed voltages (1.5 / 1.8 / 2.5 / 2.85 / 3.3 / 5.0 V) plus the adjustable version, in all three packages (SOT-223, TO-252, SO-8).

This page should be deprecated in favour of it.

Why

adom/ams1117-3-3 is one voltage of one package. Everything it carries is on the family page, and two things on it are wrong or weaker:

  1. The footprint is wrong for this part. This page ships the SnapEDA SOT229P700X180-4N pattern, which puts the tab on pad 4 as its own net. The AMS1117 tab is VOUT, internally bonded to pin 2. The family page uses KiCad's SOT-223-3_TabPin2, which bonds the tab to pad 2 correctly. A board built from this page's footprint leaves the tab floating.
  2. No datasheet, no electrical data. The family page embeds the datasheet PDF and carries the full electrical tables, thermal figures and application notes with provenance.

What replaces it

This page On the family page
AMS1117-3.3.kicad_sym ams1117.kicad_sym (family symbol, same 3 pins)
SOT229P700X180-4N.kicad_mod ams1117-sot223.kicad_mod (tab = pad 2)
AMS1117-3.3.glb ams1117-sot223.glb + .step
AMS1117-3.3.IntLib not shipped, deliberately (generated Altium libraries are not trusted)

Blocked on

  • adom/ams1117-3v3-molecule#1 - repoint its adom/ams1117-3-3 dependency at adom/ams1117 first, so nothing is depending on this page when it goes.
  • Then soft-delete this page, or keep it as a redirect stub pointing at the family page.

Related: the sibling deprecation for adom/ams1117-1-2.

2 Replies

barrett-land · 2mo ago

Update — the target of this deprecation has changed.

adom/ams1117 (the combined family page) is itself now deprecated. Merging both manufacturers onto one page meant every number needed a vendor caveat, which is the wrong shape for a datasheet page. It has been split:

  • adom/ams-ams1117 — Advanced Monolithic Systems, the original. 1.5 / 1.8 / 2.5 / 2.85 / 3.3 / 5.0 V; SOT-223 / TO-252 / SO-8.
  • adom/umw-ams1117 — UMW / Youtai Semiconductor, the second source. 1.2 / 1.5 / 1.8 / 2.5 / 3.3 / 5.0 V; SOT-223 / TO-252 / SOT-89.

Deprecate this page in favour of whichever one matches the silicon you actually buy. 3.3 V exists in both lineups, so the choice here is a sourcing question, not a technical one — check what the reels say. If this page's parts are unbranded or unknown, the AMS page is the safer default because its limits are the tighter of the two (0.9–1.5 A current limit vs 2.1–2.5 A, 15 V input max vs 18 V).

Everything else in the original report stands, including the wrong footprint: this page's SnapEDA SOT229P700X180-4N puts the tab on pad 4 as its own net, and the AMS1117 tab is VOUT = pin 2. Both replacement pages ship the correct SOT-223-3_TabPin2.

barrett-land · 2mo ago

Correction — the target page in this issue is out of date. adom/ams1117 (the combined family page I pointed at above) has itself since been deprecated and split by manufacturer, because AMS1117 is second-sourced and the two vendors do not ship the same lineup:

  • adom/ams-ams1117 — Advanced Monolithic Systems. Has 2.85 V, has SO-8, no 1.2 V.
  • adom/umw-ams1117 — UMW/Youtai. Has 1.2 V, has SOT-89, no 2.85 V.

They also differ on real limits, so one datasheet cannot stand in for the other.

Revised ask for this page: deprecate adom/ams1117-3-3 in favour of adom/ams-ams1117, since this page was built from the AMS datasheet. If the part actually fitted on boards using this page is the UMW 3.3 V, point it at adom/umw-ams1117 instead — worth a check before the redirect is written, as both vendors make a 3.3 V.

Everything else in the original report stands, in particular the footprint defect: this page ships SnapEDA SOT229P700X180-4N, which puts the tab on pad 4 as its own net, while the AMS1117 tab is VOUT bonded to pin 2. Both manufacturer pages use SOT-223-3_TabPin2, which is correct.

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