Part of the Day · AMS1117-3.3 — SOT-223 3.3V LDO regulator

Part of the Day · 2026-10-23

The SOT-223 linear regulator most commonly used to drop 5V to 3.3V. It delivers up to 1A and works with as little as 1.3V between input and output.

Actual size

↓ Actual size, left edge aligned to 0 on the ruler

One ruler tick = 1mm. On PC this is actual size on a 24-inch FHD monitor at 100% zoom; on iPhone it adjusts automatically. For other screens, use “Calibrate ruler” below.

Enlarged (SOT-223 · top view · approx. 13×)

Pins 1 GND (ADJ on the adjustable version) · 2 Output · 3 Input

Package SOT-223

Key specifications

Values are from the Advanced Monolithic Systems datasheet.

Marking and pins

Typical uses

• 5V → 3.3V supply — MCU, sensor and communication module boards
• Post regulator after a switching power supply

Companion & similar parts

• AMS1117-5.0 — Fixed 5.0V version of the same series — datasheet test condition is 6.5V input
• AMS1117 — Adjustable version of the same series — 1.25V reference, output set by two resistors on pin 1 (ADJ)
• LM317 — Adjustable regulator with the same SOT-223 pin order (1 ADJ · 2 Output · 3 Input) — 3V or more input-output difference recommended, so not for 5V→3.3V

The datasheet states that a 22µF tantalum capacitor on the output keeps it stable under all conditions. Solder the SOT-223 tab to a copper area on the PCB for good heat dissipation.