# LM2576

**Texas Instruments** · Switching Regulator (Buck) · TO-263-5

The LM2576 is a 3 A step-down (buck) switching regulator from the Simple Switcher family. It integrates the switch, oscillator (52 kHz), and control loop, so a working supply needs only an external inductor, catch diode, and capacitors. This 5 V fixed-output version drives loads up to 3 A from inputs to 40 V.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | VIN | power_in | Supply input pin to the collector of the internal high-side power transistor. Connect to the unregulated DC input (7 V to 40 V for LM2576; up to 60 V for LM2576HV). Path from VIN to the high-frequency bypass CIN and GND must be as short as possible. |
| 2 | OUTPUT | output | Emitter pin of the internal power transistor - the switching node of the buck converter. Attach this pin to the inductor and to the cathode of the external freewheeling (catch) diode. |
| 3 | GND | power_in | Device ground reference. Return path for CIN must be as short as possible for stable switching operation. |
| 4 | FEEDBACK | input | Feedback sense input. On the ADJ version, connect to the midpoint of the external resistor divider to set VOUT (VREF = 1.23 V). On fixed-output versions (3.3/5/12/15 V), connect this pin directly to the output capacitor. |
| 5 | ~{ON}/OFF | input | Active-low enable input for the regulator. HIGH = OFF (shutdown, ~50 uA typical standby); LOW = ON. Tie to GND to permanently enable the regulator. Do not leave floating. Input voltage range -0.3 V to +VIN. |

## Key specifications

| Parameter | Value |
|---|---|
| Type | Buck (step-down) switching regulator |
| Output current | 3 A |
| Output voltage | 5 V fixed (this version) |
| Input voltage | Up to 40 V |
| Switching frequency | 52 kHz typ |
| Efficiency | 77% typ |
| Line/load regulation | Internally compensated |
| Operating temperature | -40 C to 125 C (junction) |

## Ordering variants

Same part, different packaging or reel option.

- `LM2576KC`
- `LM2576KTT`
- `LM2576KTTR`

## CAD (KiCad official)

- Symbol: `lm2576.kicad_sym`
- Footprint: `lm2576.kicad_mod`
- 3D model: TO-263-5 (D2PAK) surface-mount tab body from KiCad `Package_TO_SOT_SMD/TO-263-5_TabPin3`.
- 3D model files: `lm2576-etched.step` / `lm2576-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `lm2576.step` / `lm2576.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/lit/ds/symlink/lm2576.pdf) (45 pp, sha256 `ed17313084806fc0`, retrieved 2026-08-17, tier: manufacturer)
- **Extractor:** `ds2sf` (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/lm2576-datasheet.pdf)