LM2596S-ADJ/NOPB vs MAXM38643AEMB+T: Component Comparison for Power Electronics Engineers

Quick verdict

For medium-voltage, moderate-current step-down applications requiring up to 3A output and a wide input voltage range (4.5V to 40V), the LM2596S-ADJ/NOPB is the straightforward choice due to its robustness and higher voltage flexibility. For low-voltage, compact, low-power DC/DC conversion with inputs under 5.5V, the MAXM38643AEMB+T excels by integrating a complete module in a small 10-pin package, simplifying layout and reducing design time.

Spec comparison table

SpecLM2596S-ADJ/NOPBMAXM38643AEMB+TNotes
FunctionStep-Down BuckDC-DC Converter ModuleBoth step-down, but MAXM38643AEMB+T is a fully integrated module versus a bare IC.
Input voltage max40 V5.5 VLM2596 supports much higher input voltages, enabling automotive or industrial systems.
Input voltage min4.5 V1.8 VMAXM38643AEMB+T supports lower input voltages, suitable for single-cell Li-ion and 3.3V rails.
Mounting typeSurface MountSurface MountBoth are SMT, but package sizes differ significantly.
Number of outputs11Equivalent.
Operating temperature range-40°C to 125°C (TJ)-40°C to 85°CLM2596S offers a wider operating temperature range, important for harsh environments.
Output configurationPositiveNot explicitly stated (assumed positive)Both output positive voltages; MAX module datasheet implies typical buck output.
Output current max3 ANot stated explicitly (datasheet not provided here)LM2596S rated for 3A max; MAXM38643AEMB+T current rating not explicitly listed here.
Output typeAdjustableFixed (1.8V-5.5V Input range)LM2596S output is adjustable from 1.2V up to 37V; MAXM38643AEMB+T input range specified but output voltage type unknown here.
Output voltage max37 VNot statedLM2596S supports output voltages up to 37V, suitable for a wide range of loads.
Output voltage min1.2 VNot statedLM2596S minimum output voltage is 1.2V, covers most digital rails.
Package caseTO-263-6, D2PAK (5 leads + tab)10-SMD ModuleLM2596S in a power package; MAXM38643AEMB+T is a compact module, reducing layout complexity.
Supplier device packageTO-263 (DDPAK-5)10-eMGA (2.6x2.1 mm)MAXM38643AEMB+T’s tiny package suits space-constrained designs; LM2596S larger but easier to cool.
Switching frequency typ150 kHzNot statedLM2596S switching frequency is moderate; MAXM38643AEMB+T frequency unknown here.
Synchronous rectifierNoNot statedLM2596S uses diode rectification, impacting efficiency; no data on MAXM38643AEMB+T here.
TopologyBuckBuckBoth are buck converters.

Design trade-offs

The LM2596S-ADJ/NOPB is a classic buck regulator IC designed for a wide input voltage range up to 40V and output currents up to 3A. This makes it well suited for applications with higher voltage rails such as 12V or 24V industrial supplies or automotive systems. Its TO-263 D2PAK package includes a large thermal tab for heat dissipation, which is critical given the non-synchronous topology and resulting power losses in the external catch diode. The switching frequency at 150kHz is moderate, allowing the use of larger inductors and capacitors but easing EMI filtering.

In contrast, the MAXM38643AEMB+T is a fully integrated DC/DC power module in a tiny 2.6x2.1 mm 10-pin eMGA package. The datasheet specifies an input range of 1.8V to 5.5V, indicating suitability for low-voltage, space-constrained applications such as portable devices or point-of-load regulation on 3.3V or 5V rails. The module form factor simplifies layout and BOM by integrating power components internally, though the maximum output current and switching frequency are not specified here, likely limited by the compact size and thermal constraints.

From a thermal perspective, the LM2596S can handle a wider temperature range (-40 to 125°C junction), which is important for automotive or industrial applications where ambient temperatures vary widely. The MAXM38643AEMB+T’s 85°C maximum operating temperature limits its use to less harsh environments or requires careful thermal management.

Because the LM2596S is not synchronous, efficiency at higher currents will be lower compared to synchronous designs, increasing power dissipation and necessitating larger heat sinking. The MAXM38643AEMB+T likely integrates synchronous rectification or other efficiency improvements internally, but this is not explicit from the data.

From a layout perspective, the LM2596S requires external components such as an inductor, catch diode, and feedback resistors, which increases PCB area and complexity but allows design flexibility. The MAXM38643AEMB+T’s integrated module reduces layout sensitivity and component count, speeding time to market but with less opportunity to optimize component selection.

Cost-wise, the LM2596S is a mature, widely used device likely to be cheaper in high volumes, especially if the external components are sourced economically. The MAXM38643AEMB+T module’s integration and small size typically come at a higher per-unit cost but may reduce overall system cost by saving PCB area and assembly complexity.

Use-case fit

Choose LM2596S-ADJ/NOPB when…

Choose MAXM38643AEMB+T when…

Drop-in compatibility

These two parts are not pin-compatible or footprint-compatible. The LM2596S-ADJ/NOPB is a TO-263-6 D2PAK package with 5 leads plus a thermal tab, whereas the MAXM38643AEMB+T is a 10-pin 2.6x2.1 mm eMGA surface mount module. Their different package types and pin counts mean substitution would require a PCB redesign and changes in external componentry and layout. Additionally, their input voltage ranges and output current capabilities differ significantly, so functional substitution without thorough design validation is not feasible.

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