LM2596S-ADJ/NOPB vs CLB30I1200PZ-TUB: Component Comparison
Quick verdict
For standard DC-DC step-down voltage regulation up to 3A in low to moderate voltage rails (<40V), the LM2596S-ADJ/NOPB is the clear choice due to its integrated control, adjustable output, and straightforward application. Conversely, for high-voltage, high-current AC power control or phase angle triggering applications requiring rugged thyristors, the CLB30I1200PZ-TUB is the appropriate device, offering high blocking voltage, high surge current capability, and robust thermal handling.
Spec comparison table
| Spec | LM2596S-ADJ/NOPB | CLB30I1200PZ-TUB | Notes |
|---|---|---|---|
| Function | Step-Down Buck Regulator | SCR Thyristor | Different device classes: regulator IC vs discrete thyristor. |
| Input Voltage Max (V) | 40 V | 1300 V (max) | CLB30I1200PZ-TUB supports much higher voltage; critical for high voltage AC applications. |
| Input Voltage Min (V) | 4.5 V | 1.78 V (min) | Both low, but LM2596 needs higher minimum supply voltage to operate. |
| Mounting Type | Surface Mount | Through Hole (TO-263D2) | LM2596 is SMT; CLB30I1200PZ-TUB is discrete package, generally through-hole or PCB mount. |
| Number of Outputs | 1 | 1 | Both single output devices. |
| Operating Temperature Range (°C) | -40 to 125 (TJ) | -40 to 125 (operating), -40 to 150 (storage) | Similar operating range; CLB30I1200PZ-TUB has wider storage temp. |
| Output Configuration | Positive | SCR (controlled switch) | LM2596 outputs regulated DC voltage; CLB30I1200PZ-TUB is a switch device. |
| Output Current Max (A) | 3 A | 30 A (average forward current min) | CLB30I1200PZ-TUB handles much higher current — 30A continuous vs 3A for LM2596. |
| Output Voltage Max (V) | 37 V | Not applicable | LM2596 max output voltage limited by input voltage and dropout; not relevant for SCR. |
| Output Voltage Min (V) | 1.2 V | Not applicable | LM2596 adjustable down to 1.2V; SCR output voltage is determined by load and AC line. |
| Package/Case | TO-263-6, D2PAK (5 leads + tab) | TO-263D2 | Both TO-263 variants but different pin configurations and functions. |
| Switching Frequency (typ) | 150 kHz | 60 Hz (typ) | LM2596 operates in high-frequency switching mode; CLB30I1200PZ-TUB is line-frequency device. |
| Synchronous Rectifier | No | Not applicable | LM2596 is non-synchronous; SCR is a thyristor, not a regulator. |
| Topology | Buck | Thyristor (SCR) | Different fundamental operation and application. |
| Reverse Current Min | N/A | 10 µA (min) | Relevant for SCR off-state leakage; LM2596 datasheet does not specify reverse current. |
| Reverse Current Typ | N/A | 2 mA (typ) | SCR leakage current under reverse voltage. |
| Forward Voltage Drop Min | N/A | 1.27 V (max) | SCR conduction voltage drop (~1.3-1.65V typical) affects efficiency and heat dissipation. |
| Forward Voltage Drop Typ | N/A | 1.59 - 1.65 V | |
| Average Forward Current Min | N/A | 30 A (min) | High continuous current rating for SCR. |
| RMS Forward Current | N/A | 47 A | RMS current capability of SCR. |
| Threshold Voltage Max | N/A | 0.86 V | Gate threshold voltage for SCR triggering. |
| Slope Resistance | N/A | 13.2 mΩ | SCR on-state resistance, impacts conduction losses. |
| Thermal Resistance Junction to Case | Not specified | 0.5 K/W | SCR has low thermal resistance, aiding heat sinking. |
| Thermal Resistance Case to Heatsink | Not specified | 0.25 K/W | SCR thermal management requires effective heatsinking. |
| Total Power Dissipation Max | Not specified | 250 W | SCR can dissipate high power with heatsinking. |
| Forward Surge Current Typ | N/A | 300 A | SCR surge current capability for transient overloads. |
| Gate Trigger Voltage Min | N/A | 1.6 V | Required gate voltage to trigger SCR. |
| Gate Trigger Current Min | N/A | 50 mA | Gate drive current required to turn on SCR, significant compared to typical logic levels. |
| Latching Current Typ | N/A | 115 mA | Minimum holding current after SCR turns on. |
| Holding Current Typ | N/A | 105 mA | SCR will conduct as long as current > holding current. |
| Gate Controlled Delay Time Min | N/A | 2 µs | Delay between gate trigger and conduction. |
| Turn Off Time Max | N/A | 150 µs | Time to turn off SCR after current drops below holding current; impacts switching speed. |
| Junction Capacitance | N/A | 13 pF | Affects switching transients and EMI. |
| Weight Typ | N/A | 1.5 g | SCR discrete package weight. |
| Mounting Force Min/Max | N/A | 20 N / 60 N | Mechanical considerations for mounting SCR. |
| Terminal to Terminal Distance | N/A | 4.2 - 4.7 mm | Physical terminal spacing for SCR. |
| Storage Temperature Max | Not specified | 150 °C | SCR can withstand higher storage temperatures. |
Design trade-offs
The LM2596S-ADJ/NOPB and the CLB30I1200PZ-TUB serve fundamentally different roles and are not directly comparable as drop-in replacements. The LM2596 is a monolithic integrated buck regulator IC optimized for DC-DC conversion applications, capable of regulating output voltages from 1.2V up to near input voltage with up to 3A continuous output current. Its 150kHz switching frequency allows for relatively compact LC filter components, but the lack of synchronous rectification means diode conduction losses raise conduction losses and lower efficiency compared to modern synchronous buck ICs.
Thermally, the LM2596 requires adequate copper area and possibly a heatsink when delivering near maximum current, but its 3A limit and integrated control simplify thermal design. Its TO-263-6 package offers a balance between thermal dissipation and PCB footprint, suitable for surface mount assembly.
In contrast, the CLB30I1200PZ-TUB is a discrete SCR (thyristor) designed for high voltage AC power control, capable of withstanding blocking voltages up to 1300V and continuous currents of 30A or more, with surge currents up to 300A. The device is intended for line frequency applications (50-60Hz), with switching speeds governed by gate drive and inherent turn-off time (~150 µs max). It requires a dedicated gate drive circuit capable of delivering up to 50mA at ~1.6V to trigger conduction, which is a non-trivial design consideration compared to the LM2596’s integrated control.
Thermal management for the SCR is a major design factor due to its high power dissipation capability (up to 250W max). The low thermal resistance junction-to-case (0.5 K/W) and case-to-heatsink (0.25 K/W) emphasize the need for robust heatsinking and mechanical mounting (20-60N force). The discrete package and through-hole mounting also impact PCB layout and assembly cost.
From a control perspective, the LM2596’s switching frequency and feedback loop require careful compensation and layout to minimize noise and maintain stable regulation. The SCR’s operation depends on phase-angle triggering or zero-cross detection, involving entirely different control logic and firmware considerations.
Cost-wise, the LM2596 is a low-cost, widely used regulator IC with mature design resources, while the SCR is a specialized discrete power device, generally more expensive per unit and requiring additional external components and circuitry.
Use-case fit
Choose LM2596S-ADJ/NOPB when…
- Designing a compact, surface-mount DC-DC buck converter requiring adjustable output voltage between 1.2V and 37V.
- Delivering regulated power up to 3A from DC sources between 4.5V and 40V, such as battery-powered systems or intermediate DC rails.
- Needing a relatively high switching frequency (150kHz) to reduce inductor