LM2596S-5.0/NOPB vs LM2596T-3.3/NOPB: Component Comparison
Quick verdict
For designs requiring a 5 V fixed output and surface-mount assembly, the LM2596S-5.0/NOPB is the clear choice due to its D2PAK (TO-263-6) package and standard 5 V rail compatibility. For applications targeting 3.3 V output with through-hole mounting and easier prototyping or retrofit, the LM2596T-3.3/NOPB is preferable, especially when PCB space around the regulator is limited or a vertical mounting is desired.
Spec comparison table
| Spec | LM2596S-5.0/NOPB | LM2596T-3.3/NOPB | Notes |
|---|---|---|---|
| Function | Step-Down | Step-Down | Identical function. |
| Input voltage max | 40 V | 40 V | Equal max input voltage rating. |
| Input voltage min | 4.5 V | 4.5 V | Equal min input voltage rating. |
| Mounting type | Surface Mount | Through Hole | Surface mount (LM2596S-5.0) benefits automated assembly and smaller PCB footprint; through-hole (LM2596T-3.3) better for prototyping and high-stress mechanical environments. |
| Number of outputs | 1 | 1 | Both single output. |
| Operating temperature range | -40°C to 125°C (TJ) | -40°C to 125°C (TJ) | Identical operating temperature range. |
| Output configuration | Positive | Positive | Identical. |
| Output current max | 3 A | 3 A | Identical max current capability. |
| Output type | Fixed (5.0 V) | Fixed (3.3 V) | Output voltage fixed to 5 V vs 3.3 V, select based on target rail voltage. |
| Package case | TO-263-6, D2PAK (5 leads + tab), TO-263BA | TO-220-5 Formed Leads | TO-263 surface mount vs TO-220 through-hole; affects thermal dissipation and PCB layout. |
| Supplier device package | TO-263 (DDPAK-5) | TO-220-5 | Same as above. |
| Switching frequency typ | 150 kHz | 150 kHz | Identical switching frequency. |
| Synchronous rectifier | No | No | Both use diode rectification; impacts efficiency and thermal design. |
| Topology | Buck | Buck | Same topology. |
Design trade-offs
The primary differences between the LM2596S-5.0/NOPB and the LM2596T-3.3/NOPB arise from output voltage and package style. The LM2596S-5.0 is a surface-mount device in a TO-263 (D2PAK) package, which is well-suited for automated PCB assembly and provides a low thermal resistance path through the PCB copper and the exposed tab. This can simplify thermal management on a multi-layer PCB with adequate copper area. The LM2596T-3.3, by contrast, uses a through-hole TO-220-5 package with formed leads, which is mechanically robust and easier to hand-solder but requires vertical clearance and a heat sink or larger PCB copper area for thermal management.
Both parts share the same maximum input voltage (40 V) and minimum input voltage (4.5 V), making them functionally interchangeable in terms of input range. However, the fixed output voltage difference is decisive: 5 V vs 3.3 V. This affects downstream circuitry compatibility and power budgeting. The switching frequency of 150 kHz is standard for the LM2596 family, balancing component size and efficiency.
Neither device includes synchronous rectification, so expect the usual efficiency penalties and diode losses typical of this family. This factor should be accounted for in thermal design, especially at the 3 A continuous current rating. The TO-220 package’s vertical leads and larger thermal mass can sometimes provide better heat dissipation in free air or when paired with a heat sink, but the surface-mount TO-263 can be equally effective if the PCB layout includes sufficient copper area and thermal vias.
From a layout perspective, the LM2596S-5.0’s surface-mount form factor allows for more compact and automated assembly but demands careful PCB thermal design. The LM2596T-3.3’s through-hole leads ease prototyping and rework but consume more board area and may require mechanical support. Cost-wise, TO-263 packages tend to be slightly less expensive in volume due to simpler assembly, but TO-220 parts can save costs in low-volume or repairable products.
Use-case fit
Choose LM2596S-5.0/NOPB when…
- Your design requires a fixed 5 V output rail, common in legacy logic and USB-powered devices.
- You are targeting surface-mount assembly with automated pick-and-place and reflow soldering.
- PCB area is constrained, and you can implement appropriate thermal copper area and vias to handle heat dissipation.
- You want a low-profile solution with a flat package, suitable for compact power modules.
- Your application benefits from lower mechanical stress on the regulator leads and improved vibration resistance.
Choose LM2596T-3.3/NOPB when…
- Your design needs a fixed 3.3 V output rail, typical for modern digital ICs and low-voltage logic.
- You are prototyping or building low-volume products where through-hole assembly and easy manual soldering or replacement is critical.
- Mechanical robustness and ease of heat sinking with clips or bolt-on heat sinks is required.
- You have vertical clearance and board space to accommodate the larger TO-220 footprint.
- Your application may subject the device to mechanical shock or vibration and requires stronger lead support.
Drop-in compatibility
These two devices are not pin-compatible due to differences in package and lead configuration: the LM2596S-5.0 uses a TO-263-6 (D2PAK) surface-mount package with five leads and an exposed tab, while the LM2596T-3.3 uses a through-hole TO-220-5 with formed leads. The pinouts differ in physical arrangement and orientation, making the LM2596T-3.3 not a drop-in replacement for the LM2596S-5.0 without PCB redesign.
Additionally, even if pin-compatible, the output voltage difference (5 V vs 3.3 V) means substitution impacts downstream circuitry and power supply design.
Alternatives to consider
- LM2596-ADJ (Texas Instruments): Adjustable output voltage version of the LM2596 family, allowing flexible output voltage selection via external resistors.
- MP1584 (Monolithic Power Systems): A smaller, synchronous buck converter rated for 3 A with higher efficiency and integrated synchronous rectification.
- TPS5430 (Texas Instruments): A 3 A synchronous step-down regulator with adjustable output and better efficiency at light loads, suitable for more modern designs requiring better thermal performance.