LM2596S-ADJ/NOPB vs LM2596S-ADJ: Component Comparison
Quick verdict
For standard 3A buck converter designs with a 4.5V to 40V input range and typical industrial temperature conditions, the LM2596S-ADJ/NOPB from Texas Instruments is the preferred choice due to its well-documented specs and reliability pedigree. In contrast, the LM2596S-ADJ from UMW, while functionally similar and often cheaper, has less transparent spec documentation and slightly different thermal ratings that may require additional validation in critical applications.
Spec comparison table
| Spec | LM2596S-ADJ/NOPB (TI) | LM2596S-ADJ (UMW) | Notes |
|---|---|---|---|
| Function | Step-Down Buck Regulator | Step-Down Buck Regulator | Equivalent function. |
| Input voltage max | 40 V | 40 V | Same max input voltage. |
| Input voltage min | 4.5 V | 1.2 V (min), typical 5.0 V input | UMW’s lower input voltage rating may allow operation at lower input rails. |
| Output voltage max | 37 V | 37 V | Equivalent max output voltage. |
| Output voltage min | 1.2 V | 1.2 V | Equivalent min output voltage. |
| Output current max | 3 A | 3 A | Same max output current. |
| Number of outputs | 1 | 1 | Single output in both. |
| Output type | Adjustable | Adjustable | Same output type. |
| Output configuration | Positive | Positive | Same polarity. |
| Switching frequency typ | 150 kHz | 150 kHz | Identical switching frequency. |
| Synchronous rectifier | No | No | Both use diode rectification. |
| Topology | Buck | Buck | Same topology. |
| Mounting type | Surface Mount | Surface Mount | Same mounting style. |
| Package case | TO-263-6, D2PAK (5 Leads + Tab) | TO-263-6, D2PAK (5 Leads + Tab) | Identical package outline. |
| Supplier device package | TO-263 (DDPAK-5) | TO-263-5L | Same pin count/package family. |
| Operating temperature range | -40°C to 125°C (TJ) | -40°C to 125°C (TA) | TI specifies junction temp; UMW specifies ambient temp; TI rating is more conservative. |
| Junction temperature max | Not explicitly stated | 150°C | UMW spec lists explicit max junction temp; TI datasheet does not specify max TJ. |
| Typical quiescent current | Not specified | 5 mA typical, max 10 mA | UMW provides quiescent current data; TI datasheet lacks this detail. |
| Standby/shutdown current | Not specified | 80 µA typical, max 200-250 µA | UMW specifies low standby current; TI datasheet silent. |
| Line regulation typical | Not specified | ±4% | UMW datasheet provides regulation specs; TI does not. |
| Load regulation typical | Not specified | ±4% | Same as above. |
| Feedback voltage (adj) | Not specified | 1.193 V min, 1.280 V max, 1.230 V typical | UMW provides detailed feedback voltage specs; TI datasheet does not. |
| Internal switch saturation voltage | 1.16 V (min) | 1.16 V (typ), max 1.4–1.5 V | Similar saturation voltages, UMW provides min, typ, max data. |
| Diode forward voltage drop | Not specified | 0.5 V | UMW specifies diode drop, useful for loss calculations. |
| Thermal resistance (junction-case) | Not specified | 2 °C/W typical | UMW datasheet provides thermal resistance; TI does not specify. |
| Thermal resistance (junction-ambient) | Not specified | 20–50 °C/W typical (depending on PCB copper area) | UMW provides detailed thermal resistance ranges; TI silent. |
| Max supply voltage | 40 V | 45 V (max absolute), 57 V (HV version max absolute) | UMW datasheet indicates some versions support higher max voltage (up to 57 V). |
| Lead temperature max | Not specified | 215°C | UMW specifies max lead temp for soldering. |
| Switching frequency range | 150 kHz typical | 127 kHz min, 150 kHz typical, 173 kHz max | UMW specifies oscillator frequency range; TI only typical. |
| Efficiency (typical) | Not specified | 73% typical (general), 80% @ 5 V, 90% @ 12 V | UMW provides efficiency curves; TI datasheet does not. |
| Input capacitor minimum | Not specified | 470 µF, 50 V | UMW gives input capacitor recommendations. |
| Output capacitor minimum | Not specified | 220 µF, 35 V | UMW gives output capacitor recommendations. |
| Recommended diode | Not specified | 1N5817 or equivalent | UMW specifies recommended Schottky diode. |
| On/off pin input current | Not specified | 0.02–15 µA typical/max | UMW provides on/off pin current specs; TI silent. |
Design trade-offs
Both devices are pin-compatible adjustable 3A buck converters in the TO-263 package, sharing the same switching frequency and topology. However, the most significant practical differences stem from the detailed specifications and documentation quality.
The TI LM2596S-ADJ/NOPB is a widely used, well-characterized device with a clear input voltage minimum of 4.5 V and maximum of 40 V, ensuring robust operation in typical 12 V or 24 V systems. The specified junction temperature rating (-40°C to 125°C TJ) is standard for industrial-grade parts. However, Texas Instruments’ publicly available datasheet lacks many detailed performance metrics such as quiescent current, line/load regulation percentages, oscillator frequency range, and thermal resistance values, which can complicate detailed thermal and efficiency modeling.
The UMW LM2596S-ADJ datasheet provides more granular data, including efficiency curves (73% typical overall, up to 90% at 12 V output), detailed thermal resistance figures (junction-to-case ~2°C/W, junction-to-ambient 20–50°C/W depending on PCB copper), and quiescent/standby current specs. This level of detail aids more precise thermal design and power budgeting. The UMW device also claims a somewhat wider absolute maximum supply voltage range (up to 57 V for HV versions), potentially useful in higher-voltage designs, though the standard version is rated to 40 V.
From a layout perspective, both parts require a similar footprint (TO-263-6, D2PAK with 5 leads plus tab) and typical external components (470 µF input capacitor, 220 µF output capacitor, Schottky diode like 1N5817). The UMW datasheet’s more detailed guidance on component values and thermal resistance can benefit engineers targeting tight thermal envelopes or efficiency targets.
In terms of gate drive and switching losses, both devices have similar internal switch saturation voltages (~1.16 V typical), but UMW provides max saturation voltage up to 1.5 V, which could lead to slightly higher conduction losses in worst-case scenarios. The lack of synchronous rectification in both devices means diode conduction losses dominate at light loads.
Cost-wise, UMW parts are often sourced as lower-cost alternatives, but they may require additional validation for thermal and efficiency performance in production designs due to less brand recognition and datasheet transparency.
Use-case fit
Choose LM2596S-ADJ/NOPB when…
- Designing industrial or automotive power supplies where TI’s brand reliability and well-known BOM history lower risk.
- Operating in environments with input voltages from 4.5 V up to 40 V, especially standard 12 V or 24 V rails.
- Needing a conservative junction temperature rating (-40 to 125°C TJ) backed by a major manufacturer.
- Prioritizing a proven part with abundant community and reference designs.
- When supply chain consistency and long-term availability from TI is a factor.
Choose LM2596S-ADJ when…
- Designing cost-sensitive applications where a lower unit cost is critical.
- Needing detailed thermal design data (junction-to-case and junction-to-ambient thermal resistance) for tight thermal budgets.
- Operating at input voltages potentially below 4.5 V (down to 1.2 V min input) or requiring variants with higher max input voltage (up to 57 V).
- Needing explicit quiescent and standby current specs for power budgeting in battery-powered or standby-heavy designs.
- When efficiency curves and detailed regulation specs are required to optimize system performance.
Drop-in compatibility
Both devices share the same package