What Is the LM2596? Buck (Step-Down) Regulator: Pinout and Uses
The LM2596 is a switching (buck / step-down) voltage regulator; it efficiently lowers a high input to a lower output. Unlike linears such as the 7805, it does not turn the difference into heat → high efficiency. Its input goes up to ~40 V and output to ~3 A. It needs an inductor, a catch (Schottky) diode and capacitors; on ready modules these are on the board.
The LM2596 is a switching (buck / step-down) voltage regulator: it efficiently lowers a high input to a lower output. Unlike linear regulators (such as the 7805), it does not turn the difference voltage into heat → high efficiency. For the concept, see what is a voltage regulator.
What is the LM2596 used for?
For example, getting 5 V/3.3 V from 12 V or 24 V, efficient step-down from a battery/adapter, and high-current 5 V needs. Ready-made "LM2596 buck modules" are very common (output adjustable with a pot). It removes the heating problem a linear regulator has with a large input-output difference.
LM2596 pinout (TO-220-5 / TO-263-5)
| Pin | Function |
|---|---|
| 1 | INPUT (Vin) |
| 2 | OUTPUT (switch/Vout node) |
| 3 | GND |
| 4 | FEEDBACK |
| 5 | ON/OFF (enable) |
Key electrical specifications
| Parameter | Typical value |
|---|---|
| Type | Buck (step-down), switching |
| Maximum input | ~40 V |
| Output current | up to ~3 A |
| Switching frequency | ~150 kHz |
| Output | Fixed (3.3/5/12 V) or adjustable (ADJ) |
External components
Being a buck, it does not work alone: it needs an inductor, a catch (Schottky) diode (e.g. the 1N5819) and input/output capacitors. On ready modules these are already on the board; usually all you do is set the output pot.
Limitations
- Being switching, there is some ripple/noise on the output (a sensitive analog load may need extra filtering).
- It needs more external parts than a linear (solved on modules).
- It only steps down; to step up you need a boost (e.g. the MT3608).
LM2596 equivalents and alternatives
- LM2576: a slower-switching relative.
- MP1584 / MP2307: smaller, higher-frequency bucks.
- XL4015: a high-current buck.
- 7805: the simple but inefficient linear alternative.
Find it in our catalog
To compare price and stock for the LM2596 and its alternatives, use the LM2596 search.