BETASelected output5 V · fixed version
150 kHz buck regulator
LM2596 Specifications
Review LM2596 electrical specifications, operating conditions and package details.
Package view
Key specifications
Use an inductor, catch diode and suitable input/output capacitors. The filtered output—not the switch node—feeds the load and feedback pin.
Switching frequency150 kHz typical
Junction operation−40–125 °C
Output capability3 A · design-dependent
Package details
LM2596T-5.0/NOPB · TO-220-5
| Property | Details |
|---|---|
| Manufacturer | Texas Instruments |
| Part number | LM2596T-5.0/NOPB |
| Package | TO-220-5 |
| Connections | 5 pins |
| Mounting | Through-hole |
| Lead pitch | 1.70 mm |
| Package code | NDH |
| Thermal reference | Grounded tab; thermal performance depends on board copper and cooling |
Operating envelope
Fixed 5 V option · TI SNVS124G
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Nominal output | 5 V | LM2596T-5.0 / LM2596S-5.0 |
| Specified input for 5 V regulation | 7–40 V | 0.2–3 A output load |
| Output at 25°C | 4.8–5.2 V | VIN = 7–40 V; ILOAD = 0.2–3 A |
| Output over temperature | 4.75–5.25 V | Same input/load range; TJ = −40–125°C |
| Output current | Up to 3 A | Inductor, diode, capacitors, layout and cooling must support the load |
| General supply operating range | 4.5–40 V | Does not imply a regulated 5 V output from 4.5 V input |
No specifications match. Try a parameter name or a unit.
Output accuracy includes the manufacturer’s stated conditions; do not use a headline current rating without thermal review.
Switching and control
Typical values retain their test conditions
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Oscillator | 150 kHz typical | 127–173 kHz at 25°C; 110–173 kHz over temperature |
| Switch saturation | 1.16 V typical | 3 A switch current; 1.4 V maximum at 25°C |
| Peak switch-current limit | 4.5 A typical | Protection threshold; not a continuous output rating |
| Shutdown threshold | 1.3 V typical | High = OFF; low = ON |
| Guaranteed enable / shutdown | ≤ 0.6 V / ≥ 2 V | Logic thresholds over specified temperature range |
| Standby supply current | 80 µA typical | VIN = 40 V, ON/OFF = 5 V; 200 µA maximum at 25°C |
No specifications match. Try a parameter name or a unit.
The internal switch and diode have losses; the actual duty ratio is above the ideal VOUT/VIN estimate.
12 V to 5 V example
Nominal 1 A load · illustrative component selection
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Input / output | 12 V DC / 5 V DC | Fixed-output device; pin 4 connected directly to filtered output |
| Inductor L1 | 47 µH | Choose saturation/current ratings for load, ripple and current-limit behavior |
| Catch diode D1 | 1N5825 · 5 A, 40 V Schottky | Cathode to pin 2; anode to GND; suitable for this 12 V illustration |
| Input CIN | 470 µF, 50 V | Low-ESR aluminum; check RMS ripple rating |
| Output COUT | 330 µF, 35 V | Low-ESR aluminum; check TI ESR/stability guidance |
| Load | 5 Ω · at least 10 W | 1 A nominal; resistor dissipates 5 W |
No specifications match. Try a parameter name or a unit.
The inductor, diode and capacitor values follow TI’s layout example. Validate startup, ripple, stability and thermal margins for the actual parts and conditions.
Understand the waveforms
Ideal continuous-conduction estimates
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Duty ratio | D ≈ 5 / 12 = 41.7% | Neglects switch and diode voltage drops |
| Switch period | 6.67 µs | 1 / 150 kHz |
| ON time | 2.78 µs | D / f |
| Inductor ripple | Approximately 0.414 A peak-to-peak | (12 − 5) × D / (47 µH × 150 kHz) |
| Peak current at 1 A average | Approximately 1.207 A | ILOAD + ΔIL/2 in ideal steady state |
| Output power | 5 W | 5 V × 1 A |
No specifications match. Try a parameter name or a unit.
This calculation is a teaching aid. It is not a full SPICE simulation or a guarantee of measured ripple.
Layout and package checks
Short switching loops · correct thermal-pad mapping
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Input loop | CIN → VIN → internal switch → diode → CIN return | Place CIN and diode close to the IC |
| Switch node | Pin 2 to L1 and diode cathode | Keep copper compact and away from feedback |
| Feedback | Pin 4 to COUT positive / output | Use a quiet sense route, away from switch node |
| Ground / tab | Pin 3 plus exposed metal tab | Ground plane and cooling path |
| TO-220 footprint | NDH formed-lead pattern | 1.70 mm lateral pitch; 5.80 mm nominal row stagger |
| D²PAK footprint | KTT five leads plus stepped thermal land | All pad-3 sections are GND |
No specifications match. Try a parameter name or a unit.
The downloads contain electrical pads and outlines. Check the chosen lead form, solder process and heatsinking before manufacture.
Thermal and stress limits
Separate operating conditions from stress ratings
Manufacturer specifications 6 parameters
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| Parameter | Value | Conditions / notes |
|---|---|---|
| Operating junction temperature | −40 to +125°C | Recommended range |
| Supply absolute maximum | 45 V | Stress rating; recommended VIN maximum is 40 V |
| Junction absolute maximum | 150°C | Not a normal operating target |
| Storage temperature | −65 to +150°C | Unpowered |
| TO-220 RθJA | 50°C/W | Vertical mount; approximately 1 in², 1 oz copper per TI note |
| TO-263 RθJA | 20–50°C/W in TI examples | Depends strongly on copper area and board conditions |
No specifications match. Try a parameter name or a unit.
Thermal shutdown and current limiting provide protection; they do not replace a suitable board and cooling design.
Connections by function
Select a pin for its function, connection guidance and electrical notes.