onsemi LM2576D2T-ADJR4G

Overview

LM2576D2T-ADJR4G from onsemi is a 3.0 A, adjustable-output buck switching regulator in D2PAK (TO-263) package, featuring 52 kHz fixed-frequency operation, ±4% output voltage accuracy over line/load/temperature, internal current limiting, thermal shutdown, and TTL-compatible ON/OFF control. It delivers regulated DC output from 1.23 V to 37 V and is used in industrial power supplies, battery chargers, and embedded DC-DC conversion stages.

For engineers reviewing the LM2576D2T-ADJR4G datasheet, pinout, applications, or equivalent options, key selection considerations include its 40 V max input, 3.0 A guaranteed output current, feedback reference voltage of 1.23 V, thermal shutdown behavior, and D2PAK thermal performance with R_θJC = 5.0 °C/W.

Technical Context

The LM2576D2T-ADJR4G implements a voltage-mode controlled buck converter with a built-in 52 kHz oscillator, 1.23 V precision bandgap reference, and cycle-by-cycle current limiting. Its error amplifier compares the feedback voltage against the reference to drive an internal 3.0 A NPN switch.

Operation includes automatic frequency reduction to ~18 kHz under overload or short-circuit conditions for self-protection, and TTL-level ON/OFF pin control enabling standby quiescent current as low as 80 µA. The device requires only four external components: input capacitor, output capacitor, catch diode, and inductor.

Key Specifications

Pinout & Package

D2PAK (TO-263) package with exposed thermal pad connected internally to Pin 3 (GND); heatsink surface must be soldered to PCB copper for thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buck regulator applications.

Compared with LM2576HVS-ADJ/NOPB, LM2576D2T-ADJR4G offers superior thermal performance in D2PAK but lower input voltage rating; versus MP1584EN-LF-Z, it trades higher board area and lower light-load efficiency for proven ruggedness, simpler magnetics, and legacy design compatibility.

Availability

LM2576D2T-ADJR4G is available at Aetrix Electronics and suitable for industrial power supplies, battery charger front-ends, and on-card DC-DC conversion requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LM2576D2T-ADJR4G 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

onsemi (Nasdaq: ON) is a global semiconductor leader delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The LM2576 series was designed as a monolithic, easy-to-use buck regulator family minimizing external component count while delivering robust 3 A output with integrated protection - targeting cost-sensitive, high-reliability industrial and embedded power systems.

FAQ

What is the maximum input voltage rating for LM2576D2T-ADJR4G?

The LM2576D2T-ADJR4G has a maximum input voltage rating of 40 V, with absolute maximum supply voltage specified at 45 V. Operation above 40 V risks exceeding safe operating area limits and triggering thermal shutdown. This rating makes LM2576D2T-ADJR4G suitable for 24 V and 36 V industrial bus inputs but not for 48 V systems without derating or input clamping.

How do I set the output voltage for LM2576D2T-ADJR4G?

The output voltage of LM2576D2T-ADJR4G is set using two external resistors (R1 and R2) forming a voltage divider from output to feedback pin (Pin 4) and ground. The formula is V_OUT = 1.23 V × (1 + R2/R1), with R1 typically 1.0–5.0 kΩ. For example, 1.23 V output uses R1 open and R2 = 0 Ω; 12 V uses R1 = 1.0 kΩ and R2 = 8.84 kΩ. LM2576D2T-ADJR4G requires no internal trimming - accuracy depends on resistor tolerance and temperature coefficient.

Does LM2576D2T-ADJR4G require a heatsink in typical operation?

LM2576D2T-ADJR4G does not require an external heatsink when mounted on ≥2 oz copper with ≥4 cm² thermal pad area and ambient temperature ≤50 °C at full 3 A load. Its D2PAK package features R_θJC = 5.0 °C/W, so junction temperature rise is ~15 °C above case under those conditions. At 70 °C ambient or higher current, a bolted heatsink or forced air is recommended. LM2576D2T-ADJR4G thermal shutdown activates at 150 °C junction temperature as a safety backup.

What type of catch diode should be used with LM2576D2T-ADJR4G?

A Schottky diode rated for ≥3.6 A average current and ≥50 V reverse voltage is recommended for LM2576D2T-ADJR4G, such as MBR360 (3 A, 60 V) or SR504 (5 A, 40 V). The diode must handle peak currents up to the IC's current limit (~6.9 A) and exhibit low forward voltage to minimize conduction loss. Fast recovery diodes like MUR420 are acceptable alternatives if Schottky VF or leakage is unsuitable for the application. LM2576D2T-ADJR4G datasheet Table 1 lists qualified part numbers.

Is LM2576D2T-ADJR4G RoHS compliant and Pb-free?

Yes, LM2576D2T-ADJR4G is RoHS compliant and offered in Pb-free packaging per onsemi's product marking and packaging documentation. The "R4G" suffix indicates green (halogen-free) and lead-free construction. Moisture sensitivity level is MSL 1, confirming no special handling or baking is required prior to reflow soldering. LM2576D2T-ADJR4G meets JEDEC J-STD-020D and IPC/JEDEC J-STD-033 standards for Pb-free assembly.