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Texas Instruments LM2576S-ADJ/NOPB
- Part No.:
- LM2576S-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LM2576S-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 3A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:727
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Product details
Overview
LM2576S-ADJ/NOPB from Texas Instruments is a monolithic 3-A non-synchronous step-down DC-DC converter in TO-220-5 (KC) package, delivering adjustable output voltage from 1.23 V to 37 V with ±4% regulation over line and load, 52-kHz fixed-frequency operation, and TTL-compatible ON/OFF control - used in industrial power supplies requiring high-efficiency buck conversion with minimal external components.
For engineers reviewing the LM2576S-ADJ/NOPB datasheet, LM2576S-ADJ/NOPB pinout, LM2576S-ADJ/NOPB application, or LM2576S-ADJ/NOPB equivalent, key selection considerations include input voltage range (up to 40 V), thermal performance in TO-220 package (RθJA = 32.4°C/W), feedback reference accuracy (1.23 V ±2.7%), cycle-by-cycle current limiting (ICL = 4.2–6.9 A), and shutdown quiescent current (50 µA typical).
Technical Context
The LM2576S-ADJ/NOPB implements a fixed-frequency PWM buck topology with internal 3-A NPN switch, bandgap-referenced error amplifier, and 52-kHz oscillator. Its feedback loop senses output voltage via external resistor divider connected to the FEEDBACK pin, referencing a precise 1.23-V internal reference.
It features undervoltage lockout (UVLO) behavior tied to VIN, thermal shutdown at 150°C junction temperature, and cycle-by-cycle peak current limiting that activates when inductor current exceeds 4.2–6.9 A. In overload or short-circuit conditions, oscillator frequency drops to ~11 kHz to reduce average power dissipation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3 A DC continuous - supports medium-power loads without external current boosting. |
| Input Voltage Range | 4 V to 40 V - accommodates 5 V, 12 V, 24 V, and 36 V input rails with margin for transients. |
| Output Voltage Range | 1.23 V to 37 V adjustable - set by external resistor divider; enables flexible system-level rail generation. |
| Feedback Reference | 1.23 V ±4% - determines output accuracy; tolerance directly propagates to VOUT error budget. |
| Oscillator Frequency | 52 kHz ±10% - fixed frequency simplifies EMI filtering and inductor selection vs. variable-frequency alternatives. |
| Shutdown Current | 50 µA typical - enables low-power standby mode; critical for battery-backed or energy-sensitive systems. |
| Saturation Voltage | 1.8 V max at 3 A - defines conduction loss in internal switch; impacts efficiency at low VOUT/high ILOAD. |
| Thermal Resistance | RθJA = 32.4°C/W (TO-220) - dictates heatsink requirement; 10 W dissipation raises junction temp by ~324°C above ambient. |
Pinout & Package
LM2576S-ADJ/NOPB uses the KC (TO-220-5) package with integrated heat tab electrically connected to GROUND. The 5-pin through-hole layout supports robust thermal management and straightforward prototyping on breadboards or PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VIN | Power input | Connects to unregulated DC source and input bypass capacitor; path must be short to minimize switching noise coupling. |
| 2 - OUTPUT | Switching node | Drives external inductor and catch diode anode; high dv/dt node requiring careful layout to reduce EMI. |
| 3 - GROUND | Power and signal reference | Common return for input cap, feedback network, and ON/OFF pull-down; shortest possible trace to VIN/CIN minimizes ground bounce. |
| 4 - FEEDBACK | Voltage sense input | Accepts divider midpoint voltage; 100 nA bias current allows use of high-value resistors to minimize divider power loss. |
| 5 - ON/OFF | Enable control | TTL-compatible logic input: <1.2 V = active, >1.4 V = shutdown; 50 µA standby current enables simple microcontroller control. |
| TAB | Thermal pad / GND | Internally bonded to GROUND; must be soldered to large copper pour or heatsink for thermal relief per RθJA spec. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 52-kHz switching frequency | Enables predictable EMI spectrum and simplifies LC filter design using standard off-the-shelf inductors. |
| Internal 3-A NPN power switch | Eliminates need for external MOSFET driver; reduces BOM count and layout complexity in cost-sensitive designs. |
| ±4% output voltage tolerance | Meets industrial-grade regulation requirements without trimming; applies across full line/load/temperature range. |
| Cycle-by-cycle current limiting | Provides immediate protection against short circuits and overloads without latch-up; supports safe auto-recovery. |
| TTL-compatible ON/OFF control | Allows direct interfacing with 3.3-V or 5-V logic without level-shifting; 50-µA standby current enables low-power sequencing. |
| Thermal shutdown at 150°C | Prevents permanent damage during sustained overload or poor heatsinking; device resumes operation after cooldown. |
Applications
| Industrial Motor Drives | Test & Measurement PSU |
|---|---|
Use Scenario: Powering gate drivers and logic circuitry in 24-V DC motor controllers with transient-heavy loads. IC Role / Device Role / Timing Role: Primary 3-A buck regulator generating stable 5-V or 12-V auxiliary rail from main bus. Use Value: High-current capability and thermal robustness ensure reliable operation during motor stall events without derating. |
Use Scenario: Providing clean, adjustable bench power for calibrating sensors and analog front-ends. IC Role / Device Role / Timing Role: Adjustable-output DC-DC stage enabling precise 1.23–37 V output setting via potentiometer. Use Value: ±4% regulation and low 52-kHz ripple (with proper LC filter) meet mid-tier instrumentation accuracy requirements. |
| Merchant Network PSU | Home Appliance Control Board |
Use Scenario: Generating 5-V and 12-V rails in AC-DC power supplies for Ethernet switches and PoE injectors. IC Role / Device Role / Timing Role: Secondary-side step-down regulator converting bulk 12–24 V intermediate bus to logic rails. Use Value: Requires only four external components (inductor, diode, two caps), reducing bill-of-materials and assembly cost. |
Use Scenario: Supplying MCU, display, and interface ICs in washing machines and HVAC controllers. IC Role / Device Role / Timing Role: Main 3-A DC-DC converter replacing linear regulators to eliminate heatsinks and improve efficiency. Use Value: High efficiency (>77% at 3 A) and wide input range (4–40 V) accommodate battery backup and rectified AC inputs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2576T-ADJ | Same electrical specs and pinout; TO-220-5 package with different marking and tape-and-reel packaging. | No functional difference; intended for same use cases but may differ in traceability and lot documentation. | Select LM2576T-ADJ if sourcing from distributors requiring TI's standard commercial tape-and-reel format. |
| LM2596-ADJ | Higher 150-kHz switching frequency, lower 3-A max current, improved efficiency (up to 92%), smaller external components. | Better suited for space-constrained designs; requires different inductor/capacitor values due to higher frequency. | Choose LM2596-ADJ when board area is limited and higher efficiency justifies redesign of passive components. |
Compared with LM2576S-ADJ/NOPB, LM2576T-ADJ offers identical performance in alternate packaging, while LM2596-ADJ trades legacy 52-kHz simplicity for higher frequency, better efficiency, and smaller magnetics - making it preferable for new designs where layout space and thermal headroom are constrained.
Availability
LM2576S-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial motor drives, test and measurement equipment, merchant network PSUs, and home appliance control boards requiring stable component supply and long-term manufacturability.
Supply support for LM2576S-ADJ/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor company specializing in analog, embedded processing, and power management technologies, with leadership in industrial, automotive, and communications markets.
The LM2576 series belongs to TI's SIMPLE SWITCHER® power converter family, designed specifically for engineers needing easy-to-use, high-reliability buck regulators with minimal external components and proven thermal behavior in TO-220 packages.
FAQ
What is the maximum input voltage rating for LM2576S-ADJ/NOPB?
The absolute maximum input voltage for LM2576S-ADJ/NOPB is 45 V, but the recommended operating maximum is 40 V per TI's datasheet. Exceeding 40 V risks violating recommended conditions and may accelerate degradation. The HV variant (LM2576HV-ADJ) supports up to 60 V input, but LM2576S-ADJ/NOPB is not rated for that range. Always observe derating guidelines for reliability in industrial environments.
Can LM2576S-ADJ/NOPB be used in synchronous rectification configurations?
No, LM2576S-ADJ/NOPB is a non-synchronous buck regulator with an internal NPN transistor and requires an external catch diode. It does not support synchronous rectification because it lacks a second gate driver or complementary switch control. For synchronous operation, consider TI's LMR51430 or LM76003 - both integrate high- and low-side FETs and support programmable frequency and light-load efficiency modes.
What is the purpose of the ON/OFF pin on LM2576S-ADJ/NOPB, and how should it be driven?
The ON/OFF pin on LM2576S-ADJ/NOPB enables TTL-compatible enable/disable control: logic low (<1.2 V) activates regulation, while logic high (>1.4 V) places the device in shutdown with 50 µA typical quiescent current. It must never be left floating - tie to GND via a pull-down resistor (e.g., 10 kΩ) for always-on operation, or drive directly from a microcontroller GPIO. This pin provides precise power sequencing in multi-rail systems.
How accurate is the feedback reference voltage in LM2576S-ADJ/NOPB, and how does it affect output tolerance?
The internal feedback reference voltage of LM2576S-ADJ/NOPB is 1.23 V with ±4% tolerance over temperature and line/load conditions. Since output voltage is set by VOUT = 1.23 V × (1 + R1/R2), this reference error directly contributes to overall output tolerance - e.g., a ±4% reference combined with ±1% resistor tolerance yields ~±5% total VOUT error. For tighter regulation, use precision 0.1% resistors and account for temperature drift in divider design.
Does LM2576S-ADJ/NOPB include thermal protection, and how does it behave under overload?
Yes, LM2576S-ADJ/NOPB includes thermal shutdown that activates at approximately 150°C junction temperature. When triggered, the device halts switching until junction temperature falls below the hysteresis threshold (~135°C), then resumes normal operation. Under sustained overload, it alternates between current limiting (cycle-by-cycle peak detection) and thermal shutdown - a dual-layer protection scheme that prevents catastrophic failure while allowing recovery once fault clears.
LM2576S-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.23V
- Voltage - Output (Max):
- 37V
- Current - Output:
- 3A
- Frequency - Switching:
- 52kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-5)
LM2576S-ADJ/NOPB FAQ
1.How can I place an order for LM2576S-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2576S-ADJ/NOPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LM2576S-ADJ/NOPB reliable?
The price and inventory of LM2576S-ADJ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2576S-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2576S-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2576S-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2576S-ADJ/NOPB?
LM2576S-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2576S-ADJ/NOPB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LM2576S-ADJ/NOPB?
For technical support, including LM2576S-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2576S-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2576S-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2576S-ADJ/NOPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM2576S-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2576S-ADJ/NOPB?
All LM2576S-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2576S-ADJ/NOPB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LM2576S-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2576S-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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