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LM2576SX-ADJ/NOPB

Texas Instruments

Texas Instruments SIMPLE SWITCHER® series, LM2576SX-ADJ/NOPB, step-down buck regulator, adjustable output, 3A output, 4V to 40V input, 52kHz switching, surface-mount TO-263-6 D²Pak, -40°C to 125°C junction temperature.

Texas Instruments LM2576SX-ADJ/NOPB
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[IN STOCK] In Stock: 1,056 pcs
$4.26/ pc

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MOQ 1 · Tape & Reel (TR); Cut Tape (CT) · RoHS · EIA-481 · DAP/DDP · T/T

[ORIGINAL SEALED] [PRE-SHIP HD PHOTOS] [30D WARRANTY · COC] [TRACKED DAP/DDP]

Technical specifications

LM2576SX-ADJ/NOPB specifications
Parameter / AttributeSpecification / Value
SeriesSIMPLE SWITCHER®
Output typeAdjustable
MountingSurface Mount
Voltage - input40V
Voltage - output37V
Voltage - output (Min (Fixed))1.23V
Output current3A
Frequency - switching52kHz
I/O channels1
Operating temperature-40°C~125°C(TJ)
PackageTape & Reel (TR); Cut Tape (CT)
FunctionStep-Down
TopologyBuck
CaseTO-263-6, D²Pak (5 Leads + Tab), TO-263BA
Output configurationPositive
Synchronous rectifierNo
100% Footprint Match · Solder-Ready (No PCB Redesign Needed)

Need Stock or a Drop-in Second-Source for LM2576SX-ADJ/NOPB?

Package: TO-220-5 / TO-263-5 · Pin-compatible replacements with immediate Shenzhen spot stock

Footprint Match 96%
Supply Chain & Allocation Reality:

The LM2576 is the 3A step-down that powered industrial boards and instrument supplies long before the module era: 52kHz switching, a 1.23V feedback reference, and a five-pin outline shared with its later 150kHz sibling. The substitution story has two halves: the upgrade to the LM2596 class, which is pin for pin and keeps the larger 100uH-class inductor working with lower ripple, and the fake-module story running the other way - modules marked with the newer part whose chips switch at about 50kHz with 330-470uH inductors: rebadged 2576-class dies that overheat at rated current. Read the frequency, read the inductor, then read the marking.

Verified Pin-Compatible Replacements (3 verified alternatives)

LM2596 TI / multiple TO-220-5 / TO-263-5
100% Drop-in (Zero Code Change)
Availability & Target Pricing:

The 150kHz Successor, Same Five Pins

Shenzhen Spot Stock (24-48h Dispatch)

Electrical & Core Specs:

The upgrade generation: identical pin map (1 VIN, 2 OUT, 3 GND, 4 FB, 5 ON/OFF active-low) and the same 1.23V reference, so the feedback divider carries over untouched; only the switching frequency is different - 150kHz against 52kHz.

Same 3A class up to 40V input (the HV suffix of either family lifts the ceiling to 60V).

Compatibility & Drop-In Notes: The documented fake-module tell uses exactly this pair: an LM2576-class die switching near 50kHz under a 2596 marking shows up on a scope and in the inductor size. Frequency is the fingerprint.
Package & Solder Footprint: Five-pin outline shared across TO-220 and TO-263 versions of both parts.
Shenzhen Warehouse Stock & MOQ: Both generations stocked; quote against the board magnetics.
Request Volume Quote for LM2596 Compare LM2576SX-ADJ/NOPB vs LM2596 Spec Matrix
LM2576HV TI (National lineage) TO-220-5 / TO-263-5
100% Drop-in (Zero Code Change)
Availability & Target Pricing:

The 60V Ceiling for 48V Rails

Shenzhen Spot Stock (24-48h Dispatch)

Electrical & Core Specs:

The high-voltage grade of the same die: the same 52kHz operation and five-pin map with the input ceiling raised from 40V to 60V - the part for 48V industrial rails and telecom-derived supplies.

The whole point of the grade: standard LM2576 stops at 40V input; the HV suffix is rated to 60V.

Compatibility & Drop-In Notes: The substitution rule is one-directional by safety: an HV part into a standard socket is harmless headroom; a standard part into an HV socket fails at overvoltage, usually taking the load with it. Match the grade to the rail.
Package & Solder Footprint: Identical footprint; the laser marking is the only visual difference.
Shenzhen Warehouse Stock & MOQ: Stocked; the honest answer for 48V equipment repair.
Request Volume Quote for LM2576HV Compare LM2576SX-ADJ/NOPB vs LM2576HV Spec Matrix
LM2575 TI (National lineage) TO-220-5 / TO-263-5
Functional Equivalent
Availability & Target Pricing:

The 1A Member of the Same Five Pins

Shenzhen Spot Stock (24-48h Dispatch)

Electrical & Core Specs:

The 1A tier of the same 52kHz family: identical pin map and reference, one third of the current - the right-size part for light loads that designs keep oversizing into a 3A socket.

Same input family (HV grades exist in this tier too).

Compatibility & Drop-In Notes: The substitution limit is current, not pins: fitting the 1A part where the load legitimately draws 2A ends the same way any under-rated swap does. Read the actual load first.
Package & Solder Footprint: Five-pin outline shared with the 2576 and 2596.
Shenzhen Warehouse Stock & MOQ: Stocked across the fixed 5.0/12 and adjustable grades.
Request Volume Quote for LM2575 Compare LM2576SX-ADJ/NOPB vs LM2575 Spec Matrix
Buyer & Quality Checklist for Sourcing Alternatives
  • Pin map and reference are constant across this ladder: 1 VIN, 2 OUT, 3 GND, 4 FB, 5 ON/OFF (active-low), 1.23V feedback in the adjustable grades - so the divider resistors survive an upgrade untouched, and only the magnetics move.
  • Frequency drives the magnetics: the 52kHz class asks for about 100uH with 1000uF of output capacitance in the common 5V application, the 150kHz successor uses about 33uH with 220uF. A bigger inductor on a faster part is safe (lower ripple, more size); a smaller inductor on a slow part is ripple current and poor regulation.
  • The suffix is part of the part number: the -5.0 and -12 fixed grades wire the feedback internally; the adjustable grades need the external divider. A fixed grade fitted where an adjustable part was outputs its fixed voltage whatever the divider says - check the suffix before debugging the circuit.
  • Counterfeit tell at the bench: a module marked with the 150kHz part that switches near 50kHz and carries a 330-470uH inductor holds a 2576-class die. Scope the switch node, read the inductor code - then decide whether to trust the rest of the batch.
  • The HV suffix is a voltage decision: 40V against 60V input ceiling. Substituting downward in voltage ends at the first mains transient; substituting upward is free headroom.
  • The bill of materials around the part decides the repair: the catch diode (1N5822 / SR340 class), the inductor saturation rating and 105C output capacitors. A genuine regulator in a rebuilt supply with marginal passives fails on schedule.
Frequently Asked Technical Questions

Q: Is the LM2596 a drop-in replacement for the LM2576?

A: Pin for pin, yes: the same five-pin map and the same 1.23V reference, in both TO-220 and TO-263 outlines. The existing 100uH-class inductor works on the 150kHz part with lower ripple. Moving the other way - a 52kHz part on magnetics designed for 150kHz - needs the inductor re-planned.

Q: What is the difference between LM2576 and LM2596?

A: Switching frequency: 52kHz against 150kHz, both 3A and 40V (HV grades 60V). The datasheet application circuits differ in passives - about 100uH with 1000uF against 33uH with 220uF - but the pins and the reference voltage are identical.

Q: Why do some LM2596 modules overheat at rated current?

A: Because the die inside switches near 50kHz - an LM2576-class part under a 2596 marking - and the board was built with passives from the 2596 tables. Scope the switch node frequency and read the inductor value: about 50kHz and 330-470uH means the marking is wrong.

Technical details

The Texas Instruments LM2576SX-ADJ/NOPB is a SIMPLE SWITCHER® step-down buck regulator delivering 3A continuous output from a 4V to 40V input rail. The 52kHz switching frequency keeps switching losses low and simplifies PCB layout — the trade-off is a larger inductor and higher output ripple compared to modern 500kHz+ converters. The adjustable output version lets you set Vout anywhere from 1.23V to 37V with two external resistors, covering 3.3V, 5V, 12V, and other common rails from a single BOM line.

Input headroom and thermal envelope

The 40V maximum input voltage gives margin on 24V industrial buses and 12V automotive systems, though the 52kHz switching means the input filter capacitor needs to handle the ripple current. No synchronous rectifier is used internally, so the external Schottky catch diode carries the full 3A during the off-time. The diode forward voltage and its thermal coupling to the PCB copper matter more for efficiency than the regulator itself at this switching speed.

Package and mounting — DDPAK/TO-263-5

The surface-mount DDPAK/TO-263-5 package (5 leads plus tab) is the standard footprint for 3A buck converters. The exposed tab is the thermal path and the ground connection — the PCB layout must provide a copper pour area sized for the dissipation at the target output current.

The base product number LM2576 covers the fixed-output variants (3.3V, 5V, 12V, 15V) and the adjustable version in both through-hole (TO-220) and surface-mount (D²Pak) packages. The adjustable surface-mount variant is the most flexible BOM line for multi-rail designs.

LM2576SX-ADJ/NOPB
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