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Same footprint does not mean same contract

AMS1117 vs LM1117 vs TLV1117

Three familiar SOT-223 regulators share the 1117 family shape. Their dropout, temperature grades, output-capacitor requirements, lifecycle boundaries, and even silicon identity do not collapse into one interchangeable specification.

Which 1117 regulator should you use?

For an existing board, use the exact manufacturer part whose capacitor, temperature, and dropout contract the board already satisfies. For a new design, none of these should win merely because the footprint is familiar. All require roughly a volt of conservative headroom at high load, and the legacy variants consume milliamps at idle. Start from the rail requirements, not the package silhouette.

The actual manufacturer boundaries

Values below preserve the datasheet test conditions and identity caveats. “1117-compatible” is not a substitute for an exact MPN.

PartOutput currentDropoutGround currentOutput capacitorTemperature gradeIdentity boundary
AMS1117-3.3Advanced Monolithic SystemsListed in the manufacturer product table when verified 2026-07-12; the page does not publish an explicit lifecycle field1 A headline rating; dropout is specified through 0.8 A1.1 V typical / 1.3 V maximum at 0.8 A; the datasheet notes higher dropout above 0.8 A5 mA typical / 11 mA maximum22 µF solid tantalum is the manufacturer's characterized all-conditions recommendation; no numeric ESR window is publishedSource conflict: the datasheet ordering table states −40 °C to 125 °C, while the manufacturer product table states 0 °C to 125 °C; confirm the exact orderable with AMSThis row covers the Advanced Monolithic Systems part and datasheet, not every third-party device sold under an AMS1117 marking.
LM1117-3.3Texas InstrumentsActive on TI's product page when verified 2026-07-10800 mA regulated output rating1.2 V typical at 0.8 A and 25 °C; 1.3 V maximum over the specified junction-temperature range5 mA typical / 10 mA maximum for the fixed 3.3 V versionAt least 10 µF tantalum; TI specifies an output-capacitor ESR range of 0.3 Ω to 22 ΩLM1117: 0 °C to 125 °C junction; LM1117I: −40 °C to 125 °CThe fixed 3.3 V values are for TI LM1117-3.3. The industrial-temperature LM1117I is a separate grade.
TLV1117Texas InstrumentsSOT-223 orderables were Active on TI's product data when verified 2026-07-10800 mA maximumLegacy/adjustable: 1.2 V typical at 0.8 A, with 1.3 V maximum (C grade) or 1.4 V maximum (I grade); new-chip fixed: 0.8 V typical / 1.2 V maximum at 0.8 AAdjustable/legacy: 5 mA typical; selected new-chip fixed versions: 65 µA typicalAdjustable/legacy: 10 µF class with 0.2 Ω to 10 Ω ESR; new-chip fixed: 2 mΩ to 500 mΩ ESRC grade: 0 °C to 125 °C; I grade: −40 °C to 125 °C recommended junction rangeTI documents legacy and new silicon under overlapping orderables. The packaging-label CSO identifies the die source; do not assume the new-chip numbers without controlling that source.

Decision path

  1. 01

    Maintaining a known TI LM1117 design

    Use the exact TI orderable and keep the capacitor network inside TI's characterized 10 µF minimum and 0.3 Ω to 22 Ω ESR window. A matching footprint does not prove another 1117 has the same limits.

  2. 02

    Buying an actual AMS1117-3.3

    Design from the Advanced Monolithic Systems datasheet: 1.1 V typical / 1.3 V maximum dropout at 0.8 A, 5 mA typical ground current, and the manufacturer's 22 µF solid-tantalum recommendation. Do not transfer those numbers to an unverified marketplace clone.

  3. 03

    Considering TLV1117 as an upgrade

    First decide whether you can control the silicon generation. TI documents materially different dropout, quiescent-current, and capacitor behavior across legacy and new fixed-output silicon under overlapping orderables. If you cannot control the die source, design to the legacy boundary.

  4. 04

    Starting a new low-power or battery design

    Do not choose by the familiar 1117 footprint first. Define dropout at load, ground current, capacitor technology, temperature, reverse-current behavior, and thermal loss; then select a regulator whose exact datasheet guarantees those requirements.

Run your operating point

Dropout is only half the problem. Use the linear-regulator thermal calculator to estimate dissipation, junction rise, and electrical headroom using your board inputs.

See the wider power tree

If the linear loss is unreasonable, the answer is often architectural. The PCB power-tree guide connects regulators, buck converters, protection, measurement, and bring-up.

Official manufacturer sources

Verified 2026-07-12. Confirm current revisions and orderable status before production use.