Component Comparison: LM2596S-ADJ/NOPB vs LT1372HVCS8#PBF
Quick verdict
For straightforward 3A buck converter applications with input voltages up to 40V, the LM2596S-ADJ/NOPB is the clear choice due to its higher current rating and simpler design. Conversely, when you need flexibility with multiple topologies (buck, boost, SEPIC, etc.) and a higher switching frequency for smaller magnetics, the LT1372HVCS8#PBF stands out despite its lower max current (1.5A) and narrower input voltage range.
Spec comparison table
| Spec | LM2596S-ADJ/NOPB | LT1372HVCS8#PBF | Notes |
|---|---|---|---|
| Function | Step-Down (Buck) | Buck, Boost, Cuk, Flyback, Forward, SEPIC | LT1372HVCS8#PBF supports multiple topologies, enabling greater design flexibility. |
| Input Voltage Max (V) | 40 V | 30 V | LM2596S supports higher input voltage, enabling use in 36V automotive or industrial rails. |
| Input Voltage Min (V) | 4.5 V | 2.7 V | LT1372HVCS8#PBF supports lower input voltage, better for battery-powered or low-voltage rails. |
| Mounting Type | Surface Mount | Surface Mount | Equivalent. |
| Number of Outputs | 1 | 1 | Equivalent. |
| Operating Temperature Range (TJ) | -40°C to 125°C | 0°C to 125°C | LM2596S supports wider temp range; LT1372HVCS8#PBF may be less suitable for cold environments. |
| Output Configuration | Positive | Positive or Negative | LT1372HVCS8#PBF supports negative outputs, useful in bipolar supplies. |
| Output Current Max (A) | 3 A | 1.5 A (Switch) | LM2596S provides double output current capability, critical for higher power designs. |
| Output Type | Adjustable | Adjustable | Equivalent. |
| Output Voltage Max (V) | 37 V | 42 V (Switch) | LT1372HVCS8#PBF can switch up to 42 V, enabling higher output voltage designs. |
| Output Voltage Min (V) | 1.2 V | 1.245 V | Comparable; LM2596S slightly lower minimum output voltage. |
| Package Case | TO-263-6, D2PAK (5 Leads + Tab) | 8-SOIC (0.154”, 3.90mm) | LM2596S has a larger thermal pad package better for heat dissipation; LT1372HVCS8#PBF is smaller SOIC. |
| Supplier Device Package | TO-263 (DDPAK-5) | 8-SO | As above. |
| Switching Frequency Typ (kHz) | 150 kHz | 500 kHz | LT1372HVCS8#PBF’s higher switching frequency reduces inductor/capacitor size but may increase switching losses. |
| Synchronous Rectifier | No | No | Both use diode rectification, impacting efficiency at higher currents. |
| Topology | Buck | Buck, Boost, Cuk, Flyback, Forward, SEPIC | LT1372HVCS8#PBF’s versatility suits complex power architectures. |
Design trade-offs
The LM2596S-ADJ/NOPB is a classic, robust buck regulator optimized for up to 3A current with a relatively low switching frequency of 150 kHz. This lower switching frequency simplifies EMI filtering and generally yields better efficiency at moderate loads due to reduced switching losses. The TO-263 package with a large thermal tab facilitates heat sinking, which is beneficial in applications where continuous high current leads to significant power dissipation. However, the 150 kHz frequency means larger inductors and capacitors, increasing PCB area and BOM cost.
The LT1372HVCS8#PBF trades maximum output current (1.5A max) and input voltage range (max 30V vs. 40V) for versatility and a higher switching frequency of 500 kHz. The higher frequency allows for smaller passive components, which can reduce PCB size and BOM cost in highly constrained designs. Its support for multiple topologies—buck, boost, flyback, forward, SEPIC, and Cuk—makes it suitable for complex or non-standard power conversion needs. The smaller 8-SOIC package is less thermally capable than the TO-263, making thermal design more critical and often requiring additional PCB copper area or external heat sinking to maintain junction temperatures below 125°C.
Neither device includes synchronous rectification, so both will have efficiency limitations at higher currents due to diode forward voltage drops and associated conduction losses. The LM2596S’s higher current rating makes these losses more significant, and thermal management correspondingly more challenging. The LT1372HVCS8#PBF’s lower current reduces conduction losses but also limits its use in higher power applications.
From a layout standpoint, the LM2596S benefits from the D2PAK-style package with an exposed pad for thermal conduction, which also allows for relatively straightforward placement of input and output capacitors close to the IC. The LT1372HVCS8#PBF’s SOIC package is easier to handle in automated SMT lines and fits smaller footprints but demands more careful thermal and EMI layout due to higher switching frequency and smaller package.
Cost-wise, the LM2596S is typically less expensive in volume due to its long production history and simpler buck-only function. The LT1372HVCS8#PBF’s complex feature set and higher frequency operation generally place it at a higher price point and potentially higher design complexity.
Use-case fit
Choose LM2596S-ADJ/NOPB when…
- You need a straightforward, high-current (up to 3A) buck converter with input voltages up to 40V, such as 24V or 36V industrial rails.
- Thermal management is a priority, and you want a package with a large thermal pad (TO-263) to simplify heat sinking.
- Your design can tolerate larger inductors and capacitors to optimize efficiency at moderate switching frequencies (~150 kHz).
- The application requires operation down to -40°C ambient temperature, such as automotive or outdoor industrial equipment.
- Cost sensitivity favors a proven, widely available buck regulator with minimal design complexity.
Choose LT1372HVCS8#PBF when…
- Your power supply design requires multiple conversion topologies (buck, boost, SEPIC, flyback, etc.) for flexible output voltage rails.
- The input voltage range starts as low as 2.7V, for example, battery-powered portable devices or low-voltage rails.
- PCB space constraints necessitate smaller inductors and capacitors enabled by the 500 kHz switching frequency.
- You need output voltages up to 42V or negative output rails, which the LM2596S cannot provide.
- Your design can accommodate a lower maximum output current (1.5A) and higher thermal design effort in a smaller package.
Drop-in compatibility
These two devices are not pin-compatible or footprint-compatible. The LM2596S-ADJ/NOPB comes in a TO-263-6 (D2PAK) package with 5 leads plus a thermal tab, while the LT1372HVCS8#PBF is in an 8-lead SOIC package. Their pinouts and internal topologies differ significantly due to the LT1372HVCS8#PBF’s multi-topology capability and higher switching frequency. Substituting one for the other requires a complete redesign of the PCB layout, associated magnetics, and supporting components.
Alternatives to consider
- LM2675 (Texas Instruments): A lower current (1A) but simpler buck regulator with fixed switching frequency and small package, suitable for cost-sensitive low-power designs.
- TPS5430 (Texas Instruments): A 3A buck regulator with integrated synchronous rectification, improving efficiency over LM2596S at similar current levels.
- LT1767 (Analog Devices): High-frequency synchronous buck regulator suitable for compact, high-efficiency designs needing up to ~3A output current.