LM2596T-3.3/NOPB is a Texas Instruments SIMPLE SWITCHER 3 A step-down regulator with fixed 3.3 V output in 5-lead TO-220, tube packaging — 4.5–40 V input, 150 kHz fixed switching frequency, only four external components for a complete buck, TTL shutdown, thermal shutdown and current-limit protection, 80 µA typical standby, −40 °C to +125 °C junction. The TO-220 package is the selection point: through-hole mounting with a real heatsink tab for 3.3 V logic rails that must deliver the full 3 A in hot or poorly ventilated enclosures — the tab solders to copper or bolts to a heatsink, which the SMD TO-263 cannot match for thermal headroom. Selection advice: pick the T code for through-hole assembly and heatsinked designs; pick the SX code (TO-263, tape and reel) for SMD volume production — the two are not footprint-compatible. Fixed 3.3 V removes the feedback divider and its tolerance stack; choose -ADJ only for nonstandard rails. Evidence: TI LM2596 product page confirms fixed 3.3 V, TO-220 availability and 3 A / 150 kHz operation. Match the full LM2596T-3.3/NOPB code.
Ordering-code highlights reviewed against official manufacturer documentation.
LM2596 is available in the following manufacturer order codes. They share the same LM2596 design; the table highlights package, packing and ordering differences. Quote the exact code your BOM needs.
| Order code | Package | Packing | Key difference |
|---|---|---|---|
| LM2596S-12/NOPB | TO-263-5 | Tube | Fixed 12 V output |
| LM2596S-3.3/NOPB | TO-263-5 | Tube | Fixed 3.3 V output |
| LM2596S-5.0/NOPB | TO-263-5 | TUBE | Output option is 5.0 V, while LM2596S-ADJ/NOPB is Adjustable; output circuit requires re-verification; same TO-263-5 package as LM2596S-ADJ/NOPB; this difference alone does not require PCB pad changes. |
| LM2596S-ADJ/NOPB | TO-263-5 | Tube | Adjustable output |
| LM2596SX-12/NOPB | TO-263-5 | LARGE T&R | Output option is 12 V, while LM2596S-ADJ/NOPB is Adjustable; output circuit requires re-verification; same TO-263-5 package as LM2596S-ADJ/NOPB; this difference alone does not require PCB pad changes; factory packing is LARGE T&R, 500 per pack; LM2596S-ADJ/NOPB is TUBE, 45 per pack. |
| LM2596SX-3.3/NOPB | TO-263-5 | LARGE T&R | Output option is 3.3 V, while LM2596S-ADJ/NOPB is Adjustable; output circuit requires re-verification; same TO-263-5 package as LM2596S-ADJ/NOPB; this difference alone does not require PCB pad changes; factory packing is LARGE T&R, 500 per pack; LM2596S-ADJ/NOPB is TUBE, 45 per pack. |
| LM2596SX-5.0/NOPB | TO-263-5 | Large tape and reel | Fixed 5 V output, reel |
| LM2596SX-ADJ/NOPB | TO-263-5 | LARGE T&R | Same TO-263-5 package as LM2596S-ADJ/NOPB; this difference alone does not require PCB pad changes; factory packing is LARGE T&R, 500 per pack; LM2596S-ADJ/NOPB is TUBE, 45 per pack. |
| LM2596T-12/NOPB | TO-220-5 | TUBE | Output option is 12 V, while LM2596S-ADJ/NOPB is Adjustable; output circuit requires re-verification; package/pins: TO-220 (NDH), 5 pins; LM2596S-ADJ/NOPB is TO-263 (KTT), 5 pins; do not assume direct replacement |
| LM2596T-3.3/NOPB | TO-220-5 | TUBE | Output option is 3.3 V, while LM2596S-ADJ/NOPB is Adjustable; output circuit requires re-verification; package/pins: TO-220 (NDH), 5 pins; LM2596S-ADJ/NOPB is TO-263 (KTT), 5 pins; do not assume direct replacement |
| LM2596T-5.0/NOPB | TO-220-5 | TUBE | Output option is 5.0 V, while LM2596S-ADJ/NOPB is Adjustable; output circuit requires re-verification; package/pins: TO-220 (NDH), 5 pins; LM2596S-ADJ/NOPB is TO-263 (KTT), 5 pins; do not assume direct replacement |
| LM2596T-ADJ/NOPB | TO-220-5 | TUBE | Package/pins: TO-220 (NDH), 5 pins; LM2596S-ADJ/NOPB is TO-263 (KTT), 5 pins; do not assume direct replacement — verify PCB pads, thermal and pinoutt. |
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Browse existing catalog records — same series first, then the same category and manufacturer. These are not confirmed replacements; compatibility requires engineering review.
These are order-code variants of the same Texas Instruments series. They share the core design; the ordering code selects the exact configuration — LM2596S-12/NOPB: Fixed 12 V output; LM2596S-3.3/NOPB: Fixed 3.3 V output; LM2596S-5.0/NOPB: Output option is 5.0 V, while LM2596S-ADJ/NOPB is Adjustable; output circuit requires re-verification; same TO-263-5 package as LM2596S-ADJ/NOPB; this difference alone does not require PCB pad changes.. LM2596T-3.3/NOPB itself is the TO-220-5 configuration. A code that differs by even one character may be a different device, so always quote the complete code exactly as it appears on your BOM.
From the verified technical profile: Package code: TO-220 (NDH); Pin count: 5; Operating temperature: -40 to 125 °C. These are the catalog-recorded values for LM2596T-3.3/NOPB — always re-check them against the manufacturer datasheet revision quoted on your BOM before finalizing the design.