1 A Low-Dropout Regulator UMW - AMS1117

@@ -1,45 +1,45 @@-# AMS1117 — 1 A Low-Dropout Regulator (UMW / Youtai Semiconductor)+# AMS1117: 1 A Low-Dropout Regulator (UMW / Youtai Semiconductor)  UMW's **second-source** AMS1117: a positive **1 A low-dropout linear voltage regulator** with a typical dropout of 1.2 V at the full 1 A, available in fixed 1.2 / 1.5 / 1.8 / 2.5 / 3.3 / 5.0 V versions or as an adjustable regulator set by two resistors around a 1.25 V reference. Output tolerance is 1.5 % on every fixed version except 1.2 V, which is 2 %. Includes thermal shutdown and current limiting, and takes up to 18 V in. Comes in SOT-223-3L, TO-252-2L and SOT-89-3L. -> **This page is the UMW / Youtai Semiconductor part only.** Everything here comes from the UMW datasheet and applies to UMW-branded silicon. The part number originated at Advanced Monolithic Systems, whose version has a different voltage lineup, a different third package and materially different limits — if your BOM says AMS, use [1 A Low-Dropout Regulator AMS — AMS1117](https://wiki.adom.inc/adom/ams-ams1117) instead.+> **This page is the UMW / Youtai Semiconductor part only.** Everything here comes from the UMW datasheet and applies to UMW-branded silicon. The part number originated at Advanced Monolithic Systems, whose version has a different voltage lineup, a different third package and materially different limits. If your BOM says AMS, use [1 A Low-Dropout Regulator AMS - AMS1117](https://wiki.adom.inc/adom/ams-ams1117) instead.  The interactive **symbol** and **footprint** viewers above are rendered by the wiki from the CAD shipped with this page. Use the toggle at the **bottom-right of the footprint viewer** to switch between **SOT-223**, **TO-252** and **SOT-89**.  ## Specifications -- **Output current** — 1 A-- **Fixed output voltages** — 1.2 / 1.5 / 1.8 / 2.5 / 3.3 / 5.0 V; also available adjustable-- **Output accuracy** — 1.5 % on 1.5 / 1.8 / 2.5 / 3.3 / 5.0 V and the adjustable version; **2 % on the 1.2 V version**-- **Reference voltage** — 1.250 V typ; 1.231 – 1.268 V at 25 °C, 1.225 – 1.275 V over the full range-- **Dropout voltage** — 1.00 typ / 1.20 max at 100 mA; 1.05 / 1.25 at 500 mA; **1.20 / 1.30 at 1 A**-- **Input voltage** — 18 V absolute maximum; 12 V recommended operating maximum-- **Line regulation** — 9 mV typ, 18 mV max-- **Load regulation** — 10 mV typ, 18 mV max (10 mA ≤ IOUT ≤ 1 A)-- **Current limit** — **2.1 A min, 2.5 A max**-- **Quiescent current** — 5 mA typ, 10 mA max-- **Ripple rejection** — 60 dB min, 75 dB typ (120 Hz, VIN − VOUT = 3 V)-- **Adjust pin current** — 60 µA typ, 120 µA max-- **Output voltage temperature stability** — 0.3 % typ-- **Long term stability** — 0.3 % typ (1000 h at 125 °C)-- **RMS output noise** — 0.003 % of VOUT (10 Hz – 10 kHz)-- **Protection** — current limiting and thermal shutdown at **150 °C** typ-- **Thermal resistance RθJA** — SOT-223-3L 88 °C/W, TO-252-2L 86 °C/W, SOT-89-3L 102 °C/W-- **ESD tolerance** — 2000 V minimum-- **Operating junction temperature** — −40 to +125 °C recommended, 150 °C absolute maximum; storage −65 to +150 °C-- **Soldering** — lead temperature 260 °C, 5 s-- **Required output capacitor** — 22 µF tantalum covers all cases+- **Output current**: 1 A+- **Fixed output voltages**: 1.2 / 1.5 / 1.8 / 2.5 / 3.3 / 5.0 V; also available adjustable+- **Output accuracy**: 1.5 % on 1.5 / 1.8 / 2.5 / 3.3 / 5.0 V and the adjustable version; **2 % on the 1.2 V version**+- **Reference voltage**: 1.250 V typ; 1.231 to 1.268 V at 25 °C, 1.225 to 1.275 V over the full range+- **Dropout voltage**: 1.00 typ / 1.20 max at 100 mA; 1.05 / 1.25 at 500 mA; **1.20 / 1.30 at 1 A**+- **Input voltage**: 18 V absolute maximum; 12 V recommended operating maximum+- **Line regulation**: 9 mV typ, 18 mV max+- **Load regulation**: 10 mV typ, 18 mV max (10 mA ≤ IOUT ≤ 1 A)+- **Current limit**: **2.1 A min, 2.5 A max**+- **Quiescent current**: 5 mA typ, 10 mA max+- **Ripple rejection**: 60 dB min, 75 dB typ (120 Hz, VIN − VOUT = 3 V)+- **Adjust pin current**: 60 µA typ, 120 µA max+- **Output voltage temperature stability**: 0.3 % typ+- **Long term stability**: 0.3 % typ (1000 h at 125 °C)+- **RMS output noise**: 0.003 % of VOUT (10 Hz to 10 kHz)+- **Protection**: current limiting and thermal shutdown at **150 °C** typ+- **Thermal resistance RθJA**: SOT-223-3L 88 °C/W, TO-252-2L 86 °C/W, SOT-89-3L 102 °C/W+- **ESD tolerance**: 2000 V minimum+- **Operating junction temperature**: −40 to +125 °C recommended, 150 °C absolute maximum; storage −65 to +150 °C+- **Soldering**: lead temperature 260 °C, 5 s+- **Required output capacitor**: 22 µF tantalum covers all cases  ## Pin configuration -The pinout is the same on all three packages, and **on all three the metal tab is VOUT**, internally bonded to pin 2. It is the heat path, so solder it to a copper pour on the output net — never to ground. All three footprints shipped here carry the tab as pad 2.+The pinout is the same on all three packages, and **on all three the metal tab is VOUT**, internally bonded to pin 2. It is the heat path, so solder it to a copper pour on the output net: never to ground. All three footprints shipped here carry the tab as pad 2.  | Pin | Name | I/O | Function | |---|---|---|---|-| 1 | GND/ADJ | —/O | Ground on fixed versions; adjust (feedback) node on the adjustable version |-| 2 | VOUT | O | Regulated output — also the metal tab |+| 1 | GND/ADJ |: /O | Ground on fixed versions; adjust (feedback) node on the adjustable version |+| 2 | VOUT | O | Regulated output. Also the metal tab | | 3 | VIN | I | Input supply voltage, 18 V max |-| — | TAB | — | Thermal pad, bonded to pin 2 (VOUT) |+| n/a | TAB | n/a | Thermal pad, bonded to pin 2 (VOUT) |  ### Topside marking @@ -47,22 +47,22 @@ The pinout is the same on all three packages, and **on all three the metal tab i |---|---| | SOT-223-3L | `AMS1117` / `3.3` + lot code | | TO-252-2L | `1117 CD` / `3.3` + lot code |-| SOT-89-3L | `STK17` / `3.3` + lot code — note the different prefix |+| SOT-89-3L | `STK17` / `3.3` + lot code. Note the different prefix |  ## Internal structure -The pass element is a **single NPN transistor driven by a PNP**, so dropout is set by VDROP = VBE + VSAT — which is why this family cannot get below about 1 V and why dropout rises with load. Fixed and adjustable versions are the **same die**: an on-chip link selection (F1 and F2 connected with A open for fixed, A connected with F1 and F2 open for adjustable) either wires the internal divider to the output or brings the feedback node out on pin 1.+The pass element is a **single NPN transistor driven by a PNP**, so dropout is set by VDROP = VBE + VSAT. Which is why this family cannot get below about 1 V and why dropout rises with load. Fixed and adjustable versions are the **same die**: an on-chip link selection (F1 and F2 connected with A open for fixed, A connected with F1 and F2 open for adjustable) either wires the internal divider to the output or brings the feedback node out on pin 1.  ## Component variants  All variants are the same silicon. The order code carries the **package** and the **output voltage** independently. Unlike the AMS original, UMW spells the adjustable version out as `-ADJ` rather than leaving the suffix blank. -The order code is `AMS1117` `{CD | blank}` `-{voltage | ADJ}` `{S}` — where `CD` = TO-252-2L, blank = SOT-223-3L, and a trailing `S` selects SOT-89-3L.+The order code is `AMS1117` `{CD | blank}` `-{voltage | ADJ}` `{S}`. Where `CD` = TO-252-2L, blank = SOT-223-3L, and a trailing `S` selects SOT-89-3L.  | Package | Code | Body | RθJA | Fixed order codes | |---|---|---|---|---|-| SOT-223-3L | *(none)* | 5.90–6.70 × 3.90 ±0.30 mm, 1.60 ±0.15 mm high, 2.30 mm TYP pitch | 88 °C/W | `AMS1117-1.2` … `AMS1117-5.0` |-| TO-252-2L | `CD` | 6.40–6.70 × 6.00–6.30 mm, 2.20–2.30 mm high | 86 °C/W | `AMS1117CD-1.2` … `AMS1117CD-5.0` |+| SOT-223-3L | *(none)* | 5.90 to 6.70 × 3.90 ±0.30 mm, 1.60 ±0.15 mm high, 2.30 mm TYP pitch | 88 °C/W | `AMS1117-1.2` … `AMS1117-5.0` |+| TO-252-2L | `CD` | 6.40 to 6.70 × 6.00 to 6.30 mm, 2.20 to 2.30 mm high | 86 °C/W | `AMS1117CD-1.2` … `AMS1117CD-5.0` | | SOT-89-3L | `S` | 4.50 ±0.30 × 2.45 ±0.30 mm, 1.50 ±0.20 mm thick, 3.00 mm BSC pitch | 102 °C/W | `AMS1117-1.2S` … `AMS1117-5.0S` |  The AMS original offers an **8-lead SOIC** in place of SOT-89, and a **2.85 V** version that UMW does not carry. See the [AMS page](https://wiki.adom.inc/adom/ams-ams1117).@@ -71,17 +71,17 @@ The AMS original offers an **8-lead SOIC** in place of SOT-89, and a **2.85 V**  Two limit sets per version: the tighter one at TJ = 25 °C with IOUT = 10 mA, and the wider one over the full load and line range. -| Version | VOUT typ | Min – max at 25 °C | Min – max, full range | Test VIN | Accuracy |+| Version | VOUT typ | Min to max at 25 °C | Min to max, full range | Test VIN | Accuracy | |---|---|---|---|---|---|-| AMS1117-1.2 | 1.200 V | 1.176 – 1.224 V | 1.152 – 1.248 V | 3.2 V | **2 %** |-| AMS1117-1.5 | 1.500 V | 1.477 – 1.522 V | 1.470 – 1.530 V | 3.5 V | 1.5 % |-| AMS1117-1.8 | 1.800 V | 1.773 – 1.827 V | 1.746 – 1.854 V | 3.8 V | 1.5 % |-| AMS1117-2.5 | 2.500 V | 2.462 – 2.538 V | 2.450 – 2.550 V | 4.5 V | 1.5 % |-| AMS1117-3.3 | 3.300 V | 3.250 – 3.349 V | 3.235 – 3.365 V | 5.0 V | 1.5 % |-| AMS1117-5.0 | 5.000 V | 4.925 – 5.075 V | 4.900 – 5.100 V | 7.0 V | 1.5 % |-| AMS1117-ADJ | 1.250 V ref | 1.231 – 1.268 V | 1.225 – 1.275 V | VOUT + 2 V | 1.5 % |+| AMS1117-1.2 | 1.200 V | 1.176 to 1.224 V | 1.152 to 1.248 V | 3.2 V | **2 %** |+| AMS1117-1.5 | 1.500 V | 1.477 to 1.522 V | 1.470 to 1.530 V | 3.5 V | 1.5 % |+| AMS1117-1.8 | 1.800 V | 1.773 to 1.827 V | 1.746 to 1.854 V | 3.8 V | 1.5 % |+| AMS1117-2.5 | 2.500 V | 2.462 to 2.538 V | 2.450 to 2.550 V | 4.5 V | 1.5 % |+| AMS1117-3.3 | 3.300 V | 3.250 to 3.349 V | 3.235 to 3.365 V | 5.0 V | 1.5 % |+| AMS1117-5.0 | 5.000 V | 4.925 to 5.075 V | 4.900 to 5.100 V | 7.0 V | 1.5 % |+| AMS1117-ADJ | 1.250 V ref | 1.231 to 1.268 V | 1.225 to 1.275 V | VOUT + 2 V | 1.5 % | -**Datasheet inconsistency worth knowing.** The Features bullet on page 1 claims "1.5 % output accuracy" for a list that *includes* 1.2 V, but the General Description on the same page says 1.2 V is 2 %, and the Electrical Characteristics table settles it: 1.176 – 1.224 V at 25 °C is ±2.0 %, where every other version works out to ±1.5 %. Design to **2 %** on the 1.2 V part.+**Datasheet inconsistency worth knowing.** The Features bullet on page 1 claims "1.5 % output accuracy" for a list that *includes* 1.2 V, but the General Description on the same page says 1.2 V is 2 %, and the Electrical Characteristics table settles it: 1.176 to 1.224 V at 25 °C is ±2.0 %, where every other version works out to ±1.5 %. Design to **2 %** on the 1.2 V part.  ## Assets @@ -96,23 +96,23 @@ Two limit sets per version: the tighter one at TJ = 25 °C with IOUT = 10 mA, an  ## Applications -1. [**Large Automotive Eth Switch Molecule**](https://wiki.adom.inc/adom/large-automotive-eth-switch-molecule) — an AMS1117-1.2 supplies the KSZ9131 gigabit PHY 1.2 V core rail (U902) from the board's 3.3 V rail. 1.2 V is a UMW-only version, so this is a UMW part.-2. [**1 A Low-Dropout Regulator AMS — AMS1117**](https://wiki.adom.inc/adom/ams-ams1117) — the original Advanced Monolithic Systems part.+1. [**Large Automotive Eth Switch Molecule**](https://wiki.adom.inc/adom/large-automotive-eth-switch-molecule). An AMS1117-1.2 supplies the KSZ9131 gigabit PHY 1.2 V core rail (U902) from the board's 3.3 V rail. 1.2 V is a UMW-only version, so this is a UMW part.+2. [**1 A Low-Dropout Regulator AMS - AMS1117**](https://wiki.adom.inc/adom/ams-ams1117). The original Advanced Monolithic Systems part.  ## Application notes  - **Typical circuit is 10 µF in, 22 µF out.** The output capacitor is part of the device's stability, not just decoupling. 22 µF tantalum covers every case including a bypassed adjust pin; the datasheet is explicit that stability degrades as output current rises.-- **Dropout is load-dependent and specified all the way to 1 A** — 1.20 V max at 100 mA rising to 1.30 V max at the full amp. Size the input rail from the 1 A figure unless the load is genuinely light.-- **Current limit is high.** At 2.1 – 2.5 A this part will push well past its 1 A rating into a fault before folding back, so the thermal path, not the current limit, is what protects the board. Thermal shutdown is at 150 °C.-- **Copper is the heat sink.** PD(max) = (TJ(max) − Tamb) / RθJA, and the datasheet is clear that RθJA depends on mounting technique — the 88 / 86 / 102 °C/W figures are a starting point, not a guarantee.+- **Dropout is load-dependent and specified all the way to 1 A**: 1.20 V max at 100 mA rising to 1.30 V max at the full amp. Size the input rail from the 1 A figure unless the load is genuinely light.+- **Current limit is high.** At 2.1 to 2.5 A this part will push well past its 1 A rating into a fault before folding back, so the thermal path, not the current limit, is what protects the board. Thermal shutdown is at 150 °C.+- **Copper is the heat sink.** PD(max) = (TJ(max) − Tamb) / RθJA, and the datasheet is clear that RθJA depends on mounting technique. The 88 / 86 / 102 °C/W figures are a starting point, not a guarantee. - **Adjustable output:** VOUT = VREF × (1 + R2/R1) + IADJ × R2, with VREF = 1.25 V and IADJ ≈ 60 µA.  ## Provenance -- **Datasheet:** [UMW / Youtai Semiconductor AMS1117, *1 A LDO Voltage Regulator*](docs/ams1117-datasheet-umw.pdf) — every electrical number on this page is read from it. Nothing from the Advanced Monolithic Systems datasheet is mixed in.+- **Datasheet:** [UMW / Youtai Semiconductor AMS1117, *1 A LDO Voltage Regulator*](docs/ams1117-datasheet-umw.pdf). Every electrical number on this page is read from it. Nothing from the Advanced Monolithic Systems datasheet is mixed in. - **The 2 % accuracy call on the 1.2 V version** resolves a contradiction inside the datasheet itself, in favour of the Electrical Characteristics table over the Features bullet. - **Symbol:** generated with `adom-symbol` to the datasheet's pin description table (1 = GND/ADJ, 2 = VOUT, 3 = VIN).-- **Footprints:** KiCad 10 official library land patterns, renamed — `SOT-223-3_TabPin2`, `TO-252-3_TabPin2`, `SOT-89-3`. The `TabPin2` variants are correct here because the AMS1117 tab is VOUT, which is pin 2.+- **Footprints:** KiCad 10 official library land patterns, renamed: `SOT-223-3_TabPin2`, `TO-252-3_TabPin2`, `SOT-89-3`. The `TabPin2` variants are correct here because the AMS1117 tab is VOUT, which is pin 2. - **3D models:** the matching KiCad 10 official STEP models, converted to GLB with `step2glb`. - **Canonical JSON:** imported from the KiCad symbol + SOT-223 footprint with `adom-lbr import-kicad`.-- **Fusion and Altium libraries are deliberately absent** — they are generated rather than hand-verified, and the generated Altium symbol encoding has produced wrong geometry before.+- **Fusion and Altium libraries are deliberately absent**. They are generated rather than hand-verified, and the generated Altium symbol encoding has produced wrong geometry before.

@@ -1,6 +1,6 @@ <!doctype html><html lang=en><head><meta charset=utf-8><meta name=viewport content="width=device-width,initial-scale=1"> <style>-/* Adom theme system — studio-dark token base (adom/adom-theme-system) */+/* Adom theme system: studio-dark token base (adom/adom-theme-system) */ :root{   --bg:#0d1117;--surface:#161b22;--elevated:#1c2128;--overlay:#21262d;--border:#30363d;   --text:#e6edf3;--text-body:#c9d1d9;--text-2:#8b949e;--text-3:#484f58;@@ -83,7 +83,7 @@ code{background:rgba(139,148,158,.16);padding:1px 6px;border-radius:5px;font-siz  <div class=ident><h1>AMS1117</h1><span class=mfr>UMW &middot; Youtai Semiconductor</span><span class=badge>1 A LDO &middot; UMW</span></div> <p class=oneline>UMW's <b>second-source</b> AMS1117: a positive <b>1 A low-dropout linear voltage regulator</b> with a typical dropout of <b>1.2 V at 1 A</b>, in fixed 1.2 / 1.5 / 1.8 / 2.5 / 3.3 / 5.0 V versions or an adjustable version set by two resistors around a 1.25 V reference. Output tolerance is 1.5 % on every fixed version except 1.2 V, which is 2 %. Includes thermal shutdown and current limiting, and takes up to <b>18 V</b> in. Offered in SOT-223-3L, TO-252-2L and SOT-89-3L.</p>-<div class=sib><b>This page is the UMW / Youtai Semiconductor part only.</b> Everything below comes from the UMW datasheet and applies to UMW-branded silicon. The part number originated at Advanced Monolithic Systems, whose version has a <b>different voltage lineup, a different third package and materially different limits</b> &mdash; if your BOM says AMS, use <a href="https://wiki.adom.inc/adom/ams-ams1117">1 A Low-Dropout Regulator AMS &mdash; AMS1117</a> instead.</div>+<div class=sib><b>This page is the UMW / Youtai Semiconductor part only.</b> Everything below comes from the UMW datasheet and applies to UMW-branded silicon. The part number originated at Advanced Monolithic Systems, whose version has a <b>different voltage lineup, a different third package and materially different limits</b>. If your BOM says AMS, use <a href="https://wiki.adom.inc/adom/ams-ams1117">1 A Low-Dropout Regulator AMS - AMS1117</a> instead.</div> <div class=metarow> <span class=m>Output <b>1 A</b></span><span class=m>Dropout <b>1.30 V max @ 1 A</b></span><span class=m>V<sub>IN</sub> <b>18 V max</b></span> <span class=m>Versions <b>6 fixed + ADJ</b></span><span class=m>Packages <b>SOT-223 · TO-252 · SOT-89</b></span><span class=m>Pins <b>3</b></span>@@ -102,9 +102,9 @@ code{background:rgba(139,148,158,.16);padding:1px 6px;border-radius:5px;font-siz <h2>Specifications</h2> <div> <div class=spec><span class=lbl>Output current</span><span>1 A</span></div>-<div class=spec><span class=lbl>Fixed output voltages</span><span>1.2 / 1.5 / 1.8 / 2.5 / 3.3 / 5.0 V &mdash; also available adjustable</span></div>+<div class=spec><span class=lbl>Fixed output voltages</span><span>1.2 / 1.5 / 1.8 / 2.5 / 3.3 / 5.0 V. Also available adjustable</span></div> <div class=spec><span class=lbl>Output accuracy</span><span>1.5 % on 1.5 / 1.8 / 2.5 / 3.3 / 5.0 V and the adjustable version &middot; <b>2 % on the 1.2 V version</b></span></div>-<div class=spec><span class=lbl>Reference voltage</span><span>1.250 V typ &mdash; 1.231 &ndash; 1.268 V at 25 &deg;C, 1.225 &ndash; 1.275 V over the full range</span></div>+<div class=spec><span class=lbl>Reference voltage</span><span>1.250 V typ: 1.231 to 1.268 V at 25 &deg;C, 1.225 to 1.275 V over the full range</span></div> <div class=spec><span class=lbl>Dropout voltage</span><span>1.00 typ / 1.20 max at 100 mA &middot; 1.05 / 1.25 at 500 mA &middot; <b>1.20 / 1.30 at 1 A</b></span></div> <div class=spec><span class=lbl>Input voltage</span><span>18 V absolute maximum &middot; 12 V recommended operating maximum</span></div> <div class=spec><span class=lbl>Line regulation</span><span>9 mV typ, 18 mV max (V<sub>IN(min)</sub> &le; V<sub>IN</sub> &le; 12 V, I<sub>OUT</sub> = 10 mA)</span></div>@@ -116,7 +116,7 @@ code{background:rgba(139,148,158,.16);padding:1px 6px;border-radius:5px;font-siz <div class=spec><span class=lbl>Output temperature stability</span><span>0.3 % typ</span></div> <div class=spec><span class=lbl>Temperature stability</span><span>0.5 % typ</span></div> <div class=spec><span class=lbl>Long term stability</span><span>0.3 % typ (1000 h at 125 &deg;C)</span></div>-<div class=spec><span class=lbl>RMS output noise</span><span>0.003 % of V<sub>OUT</sub> (10 Hz &ndash; 10 kHz)</span></div>+<div class=spec><span class=lbl>RMS output noise</span><span>0.003 % of V<sub>OUT</sub> (10 Hz to 10 kHz)</span></div> <div class=spec><span class=lbl>Protection</span><span>Current limiting + thermal shutdown at <b>150 &deg;C</b> typ</span></div> <div class=spec><span class=lbl>Thermal resistance R<sub>&theta;JA</sub></span><span>SOT-223-3L <b>88 &deg;C/W</b> &middot; TO-252-2L <b>86 &deg;C/W</b> &middot; SOT-89-3L <b>102 &deg;C/W</b></span></div> <div class=spec><span class=lbl>ESD tolerance</span><span>2000 V minimum</span></div>@@ -128,37 +128,37 @@ code{background:rgba(139,148,158,.16);padding:1px 6px;border-radius:5px;font-siz  <h2>Symbol &amp; footprint</h2> <div class=viewers2>-<div><div class=vh>Schematic symbol &mdash; hover a pin for its function</div>+<div><div class=vh>Schematic symbol: hover a pin for its function</div> <iframe class=vframe height=520 loading=lazy title="AMS1117 schematic symbol" src="https://wiki.adom.inc/api/v1/pages/adom/umw-ams1117/files/viewer-symbol.html"></iframe></div>-<div><div class=vh>PCB footprint &mdash; switch package bottom-right (SOT-223 / TO-252 / SOT-89)</div>+<div><div class=vh>PCB footprint: switch package bottom-right (SOT-223 / TO-252 / SOT-89)</div> <iframe class=vframe height=520 loading=lazy title="AMS1117 footprint (SOT-223 / TO-252 / SOT-89)" src="https://wiki.adom.inc/api/v1/pages/adom/umw-ams1117/files/viewer-footprints.html"></iframe></div> </div> -<h2>Pin map <span style="color:var(--text-2);font-weight:400;font-size:14px">&mdash; 3 terminals, identical across all three packages</span></h2>+<h2>Pin map <span style="color:var(--text-2);font-weight:400;font-size:14px">3 terminals, identical across all three packages</span></h2> <div class=callout>The pinout is the same on SOT-223-3L, TO-252-2L and SOT-89-3L, and <b>on all three the metal tab is V<sub>OUT</sub></b>, internally bonded to pin 2. It is the heat path, so it must be soldered to a copper pour on the output net, never to ground. All three footprints shipped here carry the tab as pad 2.</div> <div class=pinwrap> <div class=pg><div class=pgh style="border-color:#00b8b1"><span class=dot style="background:#00b8b1"></span>All packages<span class=ct>3 + tab</span></div><table class=pt><tbody> <tr><td class=pn>1</td><td class=nm>GND/ADJ</td><td class=fx>Ground on fixed versions; adjust (feedback) node on the adjustable version</td></tr>-<tr><td class=pn>2</td><td class=nm>VOUT</td><td class=fx>Regulated output &mdash; also the metal tab</td></tr>+<tr><td class=pn>2</td><td class=nm>VOUT</td><td class=fx>Regulated output. Also the metal tab</td></tr> <tr><td class=pn>3</td><td class=nm>VIN</td><td class=fx>Input supply voltage, 18 V max</td></tr>-<tr><td class=pn>&mdash;</td><td class=nm>TAB</td><td class=fx>Thermal pad, bonded to pin 2 (V<sub>OUT</sub>)</td></tr>+<tr><td class=pn>n/a</td><td class=nm>TAB</td><td class=fx>Thermal pad, bonded to pin 2 (V<sub>OUT</sub>)</td></tr> </tbody></table></div> <div class=pg><div class=pgh style="border-color:#8c6bf7"><span class=dot style="background:#8c6bf7"></span>Topside marking<span class=ct>3</span></div><table class=pt><tbody> <tr><td class=pn></td><td class=nm>SOT-223-3L</td><td class=fx><code>AMS1117</code> / <code>3.3</code> + lot code</td></tr> <tr><td class=pn></td><td class=nm>TO-252-2L</td><td class=fx><code>1117 CD</code> / <code>3.3</code> + lot code</td></tr>-<tr><td class=pn></td><td class=nm>SOT-89-3L</td><td class=fx><code>STK17</code> / <code>3.3</code> + lot code &mdash; note the different prefix</td></tr>+<tr><td class=pn></td><td class=nm>SOT-89-3L</td><td class=fx><code>STK17</code> / <code>3.3</code> + lot code. Note the different prefix</td></tr> </tbody></table></div> </div>  <h2>Internal structure</h2>-<div class=callout>The pass element is a <b>single NPN transistor driven by a PNP</b>, so dropout is set by V<sub>DROP</sub> = V<sub>BE</sub> + V<sub>SAT</sub> &mdash; which is why this family cannot get below about 1 V and why dropout rises with load. Fixed and adjustable versions are the <b>same die</b>: an on-chip link selection (F1 and F2 connected with A open for fixed, A connected with F1 and F2 open for adjustable) either wires the internal divider to the output or brings the feedback node out on pin 1.</div>+<div class=callout>The pass element is a <b>single NPN transistor driven by a PNP</b>, so dropout is set by V<sub>DROP</sub> = V<sub>BE</sub> + V<sub>SAT</sub>. Which is why this family cannot get below about 1 V and why dropout rises with load. Fixed and adjustable versions are the <b>same die</b>: an on-chip link selection (F1 and F2 connected with A open for fixed, A connected with F1 and F2 open for adjustable) either wires the internal divider to the output or brings the feedback node out on pin 1.</div>  <h2>Component variants</h2> <div class=callout>All variants are the same silicon. The order code carries the <b>package</b> and the <b>output voltage</b> independently. Unlike the AMS original, UMW spells the adjustable version out as <code>-ADJ</code> rather than leaving the suffix blank.</div> <div class=occode> <div class=ocbig><span style="color:#e6edf3">AMS1117</span><span style="color:#8c6bf7">CD</span><span style="color:#00e6dc">-3.3</span><span style="color:#64abff">S</span></div> <div class=oclegend>-<div class=ocitem><div class=octop><span class=sw style="background:#8b949e"></span><b style="color:#e6edf3">AMS1117</b></div><div class=ocdesc>base part &mdash; 1 A LDO</div></div>+<div class=ocitem><div class=octop><span class=sw style="background:#8b949e"></span><b style="color:#e6edf3">AMS1117</b></div><div class=ocdesc>base part: 1 A LDO</div></div> <div class=ocitem><div class=octop><span class=sw style="background:#8c6bf7"></span><b style="color:#a98bf9">CD / blank</b></div><div class=ocdesc><code>CD</code> = TO-252-2L &middot; blank = SOT-223-3L</div></div> <div class=ocitem><div class=octop><span class=sw style="background:#00e6dc"></span><b style="color:#00e6dc">-3.3 / -ADJ</b></div><div class=ocdesc>fixed output voltage, or <code>-ADJ</code> for the adjustable version</div></div> <div class=ocitem><div class=octop><span class=sw style="background:#64abff"></span><b style="color:#8fc6ff">S</b></div><div class=ocdesc>trailing <code>S</code> selects SOT-89-3L</div></div>@@ -167,17 +167,17 @@ code{background:rgba(139,148,158,.16);padding:1px 6px;border-radius:5px;font-siz <div class=vgrid> <div class=vcard> <h3>SOT-223-3L<span class=chip style="background:rgba(139,148,158,.18);color:#8b949e">no letter</span></h3>-<div class=sub>5.90&ndash;6.70 &times; 3.90 &plusmn;0.30 mm body, 1.60 &plusmn;0.15 mm height &middot; 2.30 mm TYP lead pitch &middot; 4.60 &plusmn;0.15 mm lead span &middot; tab = V<sub>OUT</sub></div>+<div class=sub>5.90 to 6.70 &times; 3.90 &plusmn;0.30 mm body, 1.60 &plusmn;0.15 mm height &middot; 2.30 mm TYP lead pitch &middot; 4.60 &plusmn;0.15 mm lead span &middot; tab = V<sub>OUT</sub></div> <div class=oc><b>Fixed:</b> <code>AMS1117-1.2</code> <code>-1.5</code> <code>-1.8</code> <code>-2.5</code> <code>-3.3</code> <code>-5.0</code></div> <div class=oc><b>Adjustable:</b> <code>AMS1117-ADJ</code></div> <div class=oc>R<sub>&theta;JA</sub> <b>88 &deg;C/W</b></div> </div> <div class=vcard> <h3>TO-252-2L <code style="font-size:13px">CD</code></h3>-<div class=sub>6.40&ndash;6.70 &times; 6.00&ndash;6.30 mm body, 2.20&ndash;2.30 mm height &middot; 2.20&ndash;2.40 mm lead pitch &middot; tab = V<sub>OUT</sub></div>+<div class=sub>6.40 to 6.70 &times; 6.00 to 6.30 mm body, 2.20 to 2.30 mm height &middot; 2.20 to 2.40 mm lead pitch &middot; tab = V<sub>OUT</sub></div> <div class=oc><b>Fixed:</b> <code>AMS1117CD-1.2</code> <code>-1.5</code> <code>-1.8</code> <code>-2.5</code> <code>-3.3</code> <code>-5.0</code></div> <div class=oc><b>Adjustable:</b> <code>AMS1117CD-ADJ</code></div>-<div class=oc>R<sub>&theta;JA</sub> <b>86 &deg;C/W</b> &mdash; the best thermal option</div>+<div class=oc>R<sub>&theta;JA</sub> <b>86 &deg;C/W</b>. The best thermal option</div> </div> <div class=vcard> <h3>SOT-89-3L <code style="font-size:13px">S</code></h3>@@ -191,16 +191,16 @@ code{background:rgba(139,148,158,.16);padding:1px 6px;border-radius:5px;font-siz  <h2>Output voltage versions</h2> <p style="color:var(--text-2);font-size:14px;margin:0 0 10px">Two limit sets per version: the tighter one at T<sub>J</sub> = 25 &deg;C with I<sub>OUT</sub> = 10 mA, and the wider one over the full load and line range (0 or 10 mA &le; I<sub>OUT</sub> &le; 1 A).</p>-<table class=vt><thead><tr><th>Version</th><th>V<sub>OUT</sub> typ</th><th>Min &ndash; max at 25 &deg;C</th><th>Min &ndash; max, full range</th><th>Test V<sub>IN</sub></th><th>Accuracy</th></tr></thead><tbody>-<tr><td>AMS1117-1.2</td><td>1.200 V</td><td>1.176 &ndash; 1.224 V</td><td>1.152 &ndash; 1.248 V</td><td>3.2 V</td><td><b>2 %</b></td></tr>-<tr><td>AMS1117-1.5</td><td>1.500 V</td><td>1.477 &ndash; 1.522 V</td><td>1.470 &ndash; 1.530 V</td><td>3.5 V</td><td>1.5 %</td></tr>-<tr><td>AMS1117-1.8</td><td>1.800 V</td><td>1.773 &ndash; 1.827 V</td><td>1.746 &ndash; 1.854 V</td><td>3.8 V</td><td>1.5 %</td></tr>-<tr><td>AMS1117-2.5</td><td>2.500 V</td><td>2.462 &ndash; 2.538 V</td><td>2.450 &ndash; 2.550 V</td><td>4.5 V</td><td>1.5 %</td></tr>-<tr><td>AMS1117-3.3</td><td>3.300 V</td><td>3.250 &ndash; 3.349 V</td><td>3.235 &ndash; 3.365 V</td><td>5.0 V</td><td>1.5 %</td></tr>-<tr><td>AMS1117-5.0</td><td>5.000 V</td><td>4.925 &ndash; 5.075 V</td><td>4.900 &ndash; 5.100 V</td><td>7.0 V</td><td>1.5 %</td></tr>-<tr><td>AMS1117-ADJ</td><td>1.250 V ref</td><td>1.231 &ndash; 1.268 V</td><td>1.225 &ndash; 1.275 V</td><td>V<sub>OUT</sub>+2 V</td><td>1.5 %</td></tr>+<table class=vt><thead><tr><th>Version</th><th>V<sub>OUT</sub> typ</th><th>Min to max at 25 &deg;C</th><th>Min to max, full range</th><th>Test V<sub>IN</sub></th><th>Accuracy</th></tr></thead><tbody>+<tr><td>AMS1117-1.2</td><td>1.200 V</td><td>1.176 to 1.224 V</td><td>1.152 to 1.248 V</td><td>3.2 V</td><td><b>2 %</b></td></tr>+<tr><td>AMS1117-1.5</td><td>1.500 V</td><td>1.477 to 1.522 V</td><td>1.470 to 1.530 V</td><td>3.5 V</td><td>1.5 %</td></tr>+<tr><td>AMS1117-1.8</td><td>1.800 V</td><td>1.773 to 1.827 V</td><td>1.746 to 1.854 V</td><td>3.8 V</td><td>1.5 %</td></tr>+<tr><td>AMS1117-2.5</td><td>2.500 V</td><td>2.462 to 2.538 V</td><td>2.450 to 2.550 V</td><td>4.5 V</td><td>1.5 %</td></tr>+<tr><td>AMS1117-3.3</td><td>3.300 V</td><td>3.250 to 3.349 V</td><td>3.235 to 3.365 V</td><td>5.0 V</td><td>1.5 %</td></tr>+<tr><td>AMS1117-5.0</td><td>5.000 V</td><td>4.925 to 5.075 V</td><td>4.900 to 5.100 V</td><td>7.0 V</td><td>1.5 %</td></tr>+<tr><td>AMS1117-ADJ</td><td>1.250 V ref</td><td>1.231 to 1.268 V</td><td>1.225 to 1.275 V</td><td>V<sub>OUT</sub>+2 V</td><td>1.5 %</td></tr> </tbody></table>-<div class=callout style="margin-top:14px"><b>Datasheet inconsistency worth knowing.</b> The Features bullet on page 1 claims "1.5 % output accuracy" for a list that <b>includes</b> 1.2 V, but the General Description on the same page says 1.2 V is <b>2 %</b>, and the Electrical Characteristics table settles it: 1.176 &ndash; 1.224 V at 25 &deg;C is &plusmn;2.0 %, where every other version works out to &plusmn;1.5 %. Design to <b>2 %</b> on the 1.2 V part.</div>+<div class=callout style="margin-top:14px"><b>Datasheet inconsistency worth knowing.</b> The Features bullet on page 1 claims "1.5 % output accuracy" for a list that <b>includes</b> 1.2 V, but the General Description on the same page says 1.2 V is <b>2 %</b>, and the Electrical Characteristics table settles it: 1.176 to 1.224 V at 25 &deg;C is &plusmn;2.0 %, where every other version works out to &plusmn;1.5 %. Design to <b>2 %</b> on the 1.2 V part.</div>  <h2>Assets</h2> <p style="color:var(--text-2);font-size:14px;margin:0 0 10px">KiCad symbol, all three footprints and matching 3D models, plus the canonical <b>adom-lbr JSON</b> the rest is generated from.</p>@@ -215,16 +215,16 @@ code{background:rgba(139,148,158,.16);padding:1px 6px;border-radius:5px;font-siz  <h2>Implementation</h2> <ul class=ul>-<li><a href="https://wiki.adom.inc/adom/large-automotive-eth-switch-molecule"><b>Large Automotive Eth Switch Molecule</b></a> &mdash; an AMS1117-1.2 supplies the KSZ9131 gigabit PHY 1.2 V core rail (U902) from the board's 3.3 V rail. 1.2 V is a UMW-only version, so this is a UMW part.</li>-<li><a href="https://wiki.adom.inc/adom/ams-ams1117"><b>1 A Low-Dropout Regulator AMS &mdash; AMS1117</b></a> &mdash; the original Advanced Monolithic Systems part. Adds 2.85 V and an 8-lead SOIC; drops 1.2 V and SOT-89.</li>+<li><a href="https://wiki.adom.inc/adom/large-automotive-eth-switch-molecule"><b>Large Automotive Eth Switch Molecule</b></a>. An AMS1117-1.2 supplies the KSZ9131 gigabit PHY 1.2 V core rail (U902) from the board's 3.3 V rail. 1.2 V is a UMW-only version, so this is a UMW part.</li>+<li><a href="https://wiki.adom.inc/adom/ams-ams1117"><b>1 A Low-Dropout Regulator AMS - AMS1117</b></a>. The original Advanced Monolithic Systems part. Adds 2.85 V and an 8-lead SOIC; drops 1.2 V and SOT-89.</li> </ul>  <h2>Application notes</h2> <ul class=ul> <li><b>Typical circuit is 10 &micro;F in, 22 &micro;F out.</b> The output capacitor is part of the device's stability, not just decoupling. 22 &micro;F tantalum covers every case including a bypassed adjust pin; without adjust-pin bypassing, smaller values work, but the datasheet is explicit that stability degrades as output current rises.</li>-<li><b>Dropout is load-dependent, and specified all the way to 1 A</b> &mdash; 1.20 V max at 100 mA rising to 1.30 V max at the full amp. Size the input rail from the 1 A figure unless the load is genuinely light.</li>-<li><b>Current limit is high.</b> At 2.1 &ndash; 2.5 A this part will happily push well past its 1 A rating into a fault before folding back, so the thermal path, not the current limit, is what protects the board. Thermal shutdown is at 150 &deg;C.</li>-<li><b>Copper is the heat sink.</b> P<sub>D(max)</sub> = (T<sub>J(max)</sub> &minus; T<sub>amb</sub>) / R<sub>&theta;JA</sub>, and the datasheet is clear that R<sub>&theta;JA</sub> depends on mounting technique &mdash; the 88 / 86 / 102 &deg;C/W figures are a starting point, not a guarantee.</li>+<li><b>Dropout is load-dependent, and specified all the way to 1 A</b>: 1.20 V max at 100 mA rising to 1.30 V max at the full amp. Size the input rail from the 1 A figure unless the load is genuinely light.</li>+<li><b>Current limit is high.</b> At 2.1 to 2.5 A this part will happily push well past its 1 A rating into a fault before folding back, so the thermal path, not the current limit, is what protects the board. Thermal shutdown is at 150 &deg;C.</li>+<li><b>Copper is the heat sink.</b> P<sub>D(max)</sub> = (T<sub>J(max)</sub> &minus; T<sub>amb</sub>) / R<sub>&theta;JA</sub>, and the datasheet is clear that R<sub>&theta;JA</sub> depends on mounting technique. The 88 / 86 / 102 &deg;C/W figures are a starting point, not a guarantee.</li> <li><b>Adjustable output:</b> V<sub>OUT</sub> = V<sub>REF</sub> &times; (1 + R2/R1) + I<sub>ADJ</sub> &times; R2, with V<sub>REF</sub> = 1.25 V and I<sub>ADJ</sub> &asymp; 60 &micro;A.</li> </ul> @@ -234,10 +234,10 @@ code{background:rgba(139,148,158,.16);padding:1px 6px;border-radius:5px;font-siz  <h2>Provenance</h2> <ul class=ul>-<li><b>Every electrical number on this page</b> is read from the UMW / Youtai Semiconductor datasheet embedded above &mdash; description, features and nomenclature from page 1, absolute maximums and recommended operating conditions from page 2, the Electrical Characteristics table from page 3, pin configuration and function description from page 4, application circuits from page 5, and package outlines from pages 7&ndash;8. Nothing from the Advanced Monolithic Systems datasheet is mixed in.</li>+<li><b>Every electrical number on this page</b> is read from the UMW / Youtai Semiconductor datasheet embedded above: description, features and nomenclature from page 1, absolute maximums and recommended operating conditions from page 2, the Electrical Characteristics table from page 3, pin configuration and function description from page 4, application circuits from page 5, and package outlines from pages 7 to 8. Nothing from the Advanced Monolithic Systems datasheet is mixed in.</li> <li><b>The 2 % accuracy call on the 1.2 V version</b> resolves a contradiction inside the datasheet itself, in favour of the Electrical Characteristics table over the Features bullet. See the note under the version table.</li> <li><b>Symbol:</b> generated with <code>adom-symbol</code> to the datasheet's pin description table (1 = GND/ADJ, 2 = VOUT, 3 = VIN).</li>-<li><b>Footprints:</b> the KiCad 10 official library land patterns, renamed &mdash; <code>SOT-223-3_TabPin2</code>, <code>TO-252-3_TabPin2</code> and <code>SOT-89-3</code>. The <code>TabPin2</code> variants are correct here because the AMS1117 tab is V<sub>OUT</sub>, which is pin 2.</li>+<li><b>Footprints:</b> the KiCad 10 official library land patterns, renamed: <code>SOT-223-3_TabPin2</code>, <code>TO-252-3_TabPin2</code> and <code>SOT-89-3</code>. The <code>TabPin2</code> variants are correct here because the AMS1117 tab is V<sub>OUT</sub>, which is pin 2.</li> <li><b>3D models:</b> the matching KiCad 10 official STEP models (<code>SOT-223.step</code>, <code>TO-252-3_TabPin2.step</code>, <code>SOT-89-3.step</code>), converted to GLB with <code>step2glb</code>.</li> <li><b>Canonical JSON:</b> <code>ams1117.adom-lbr.json</code>, imported from the KiCad symbol + SOT-223 footprint with <code>adom-lbr import-kicad</code>.</li> <li><b>Fusion and Altium libraries are deliberately absent.</b> They are generated rather than hand-verified, and the generated Altium symbol encoding has produced wrong geometry before, so nothing is shipped here until it can be checked in the tool itself.</li>