# LM317MG-AA3-R

**UTC(Unisonic Tech)** · Linear Voltage Regulators (LDO) · SOT-223

LM317MG-AA3-R from UTC(Unisonic Tech), in a SOT-223. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | ADJ | input | Adjust pin that sets the output voltage via the reference (VREF 1.20-1.30V, typical IADJ 50 µA); a CADJ capacitor may be connected between ADJ and ground. |
| 2 | VOUT | power_out | Regulated output pin, adjustable from 1.2V to 37V and supplying over 500mA, with minimum load current for regulation of 3.5mA typical (10mA max). |
| 3 | VIN | power_in | Unregulated input pin, with maximum input-output voltage differential of 40V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | UTC(Unisonic Tech) |
| Package | SOT-223 |
| Category | Power Management ICs |
| Pins | 3 |

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Line Regulation | ΔVOUT/VOUT |  | 0.01 | 0.04 | %/V | 3V≦VIN-VOUT≦40V | 3 |
| Load Regulation (VOUT≦5V) | ΔVOUT |  | 5 | 25 | mV | 10mA≦IOUT≦0.5A, VOUT≦5V | 3 |
| Load Regulation (VOUT≧5V) | ΔVOUT |  | 0.1 | 0.5 | % | 10mA≦IOUT≦0.5A, VOUT≧5V | 3 |
| Adjustable Pin Current | IADJ |  | 50 | 100 | μA |  | 3 |
| Adjustable Pin Current Change | ΔIADJ |  | 0.2 | 5 | μA | 3V≦VIN-VOUT≦40V, 10mA≦IOUT≦0.5A, PD＜7.5W | 3 |
| Reference Voltage | VREF | 1.2 | 1.25 | 1.3 | V | 3V≦VIN-VOUT≦40V, 10mA≦IOUT≦0.5A, PD＜7.5W | 3 |
| Minimum Load Current for Regulation | IL(MIN) |  | 3.5 | 10 | mA | VIN-VOUT=40V | 3 |
| Maximum Output Current | IO(MAX) | 0.1 | 0.2 |  | A | VIN-VOUT=40V, PD≦7.5W | 3 |
| Ripple Rejection (CADJ=10F) | RR | 66 | 80 |  | dB | VOUT=10V, f=120HZ, CADJ=10F | 3 |
| Input-Output Voltage Differential | VIN-VOUT |  |  | 40 | V |  | 3 |
| Junction Temperature | TJ |  |  | 125 | °C |  | 3 |
| Operating Temperature | TOPR | -40 |  | 85 | °C |  | 3 |
| Storage Temperature | TSTG | -40 |  | 150 | °C |  | 3 |
| Thermal Resistance Junction to Ambient | θJA |  |  | 165 | °C/W | SOT-223 | 3 |
| Thermal Resistance Junction to Case | θJC |  |  | 24 | °C/W | SOT-223 | 3 |
| Temperature Stability |  |  | 0.7 |  | %/VOUT | TMIN≦TJ≦TMAX | 3 |
| RMS Noise vs. % of VOUT | eN |  | 0.003 |  | %/VOUT | 10HZ≦f≦10KHZ | 3 |
| Ripple Rejection (CADJ=0) | RR |  | 65 |  | dB | VOUT=10V, f=120HZ, CADJ=0 | 3 |

## CAD (KiCad official)

- Symbol: `LM317MG-AA3-R`
- Footprint: `Package_TO_SOT_SMD:SOT-223-3_TabPin2`
- 3D model: SOT-223 (KiCad packages3D, STEP)
- 3D model files: `lm317mg-aa3-r-etched.step` / `lm317mg-aa3-r-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `lm317mg-aa3-r.step` / `lm317mg-aa3-r.glb` are the bare package body.

## Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

- **Datasheet:** [UTC(Unisonic Tech) datasheet](docs/lm317mg-aa3-r-datasheet.pdf) (5 pp, sha256 `39896e9ce757093c`, retrieved 2026-10-23, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text), consensus `claude-sonnet-5-5` (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/lm317mg-aa3-r-datasheet.pdf)