onsemi LM2575D2T-3.3G

Overview

LM2575D2T-3.3G from onsemi is a monolithic step-down (buck) switching regulator IC delivering 1.0 A output current at fixed 3.3 V with ±4% output voltage tolerance, 52 kHz internal oscillator frequency, and wide 4.75 V to 40 V input range. It integrates a 1.0 A switch, thermal shutdown, cycle-by-cycle current limiting, and TTL-compatible ON/OFF control-designed for compact, high-efficiency DC-DC conversion in industrial power supplies and embedded systems.

For engineers reviewing the LM2575D2T-3.3G datasheet, pinout, applications, or equivalent options, key selection considerations include guaranteed 1.0 A load capability across −40°C to +125°C, 75% typical efficiency at 12 V_IN/1.0 A, D2PAK (TO-263) package thermal performance (R_θJC = 5.0°C/W), and compatibility with standard off-the-shelf inductors (e.g., 330 µH).

Technical Context

The LM2575D2T-3.3G implements a voltage-mode controlled buck topology with a fixed 52 kHz oscillator and internal 1.235 V bandgap reference. Its error amplifier compares feedback voltage against this reference to drive a 1.0 A NPN switch via a fixed-gain comparator and driver stage.

Protection features include cycle-by-cycle current limiting (1.7–3.0 A peak), thermal shutdown activation at ~150°C junction temperature, and 80 µA typical standby current when the ON/OFF pin is pulled high. The device operates in continuous conduction mode and requires only four external components: input capacitor, output capacitor, catch diode (e.g., 1N5819), and inductor.

Key Specifications

Pinout & Package

D2PAK (TO-263-5) package with exposed thermal pad connected internally to Pin 3 (GND); heatsink surface must be soldered to PCB copper area for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down regulator applications.

Compared with LM2575T-3.3G, the LM2575D2T-3.3G offers superior thermal performance in compact layouts; compared with MP1584EN-LF-Z, it trades higher frequency for proven EMI behavior and simpler external component selection-ideal for cost-sensitive, thermally constrained industrial designs.

Availability

LM2575D2T-3.3G is available at Aetrix Electronics and suitable for industrial automation power supplies, automotive body electronics, and medical handheld devices requiring stable component supply and long-term manufacturability.

Supply support for LM2575D2T-3.3G 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 (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, and sensing technologies for automotive, industrial, and cloud infrastructure markets.

The LM2575 series was designed as a drop-in upgrade path from linear regulators-emphasizing minimal external components, rugged fault protection, and broad input voltage tolerance for harsh-environment power conversion.

FAQ

What is the maximum input voltage rating for LM2575D2T-3.3G?

The absolute maximum input voltage for LM2575D2T-3.3G is 45 V, but the recommended operating maximum is 40 V per the datasheet's operating ratings. Exceeding 40 V risks violating safe operating area limits during transients, even with proper input capacitance. The device maintains regulation and protection functionality across its full 4.75 V to 40 V input range, making LM2575D2T-3.3G suitable for 24 V industrial buses and automotive applications with load-dump immunity.

Does LM2575D2T-3.3G require an external feedback resistor network?

No, LM2575D2T-3.3G is a fixed-output version with internal resistor divider set to 3.3 V; Pin 4 (Feedback) is internally connected and not accessible to the user. Unlike the adjustable LM2575ADJ variant, LM2575D2T-3.3G needs no external R1/R2 resistors-reducing component count, layout area, and potential drift sources. This simplifies design validation and improves long-term output stability in field-deployed LM2575D2T-3.3G systems.

What thermal performance can be expected from the D2PAK package of LM2575D2T-3.3G?

LM2575D2T-3.3G in D2PAK has R_θJC = 5.0°C/W and R_θJA = 70°C/W (with 1 in² 2-oz copper). With proper PCB heatsinking (exposed pad soldered to ≥1 in² ground plane), it sustains 1.0 A continuous output at +70°C ambient without external heatsink. At 1.0 A and 12 V_IN, power dissipation is ~8.7 W; junction temperature rise is ~43.5°C above ambient-well within the 125°C max operating limit. This makes LM2575D2T-3.3G viable for enclosed industrial enclosures.

Can LM2575D2T-3.3G be used in automotive applications?

Yes-while LM2575D2T-3.3G itself is not AEC-Q100 certified, it belongs to the LM2575 family whose NCV2575 automotive-grade variants (e.g., NCV2575D2T-3.3G) are AEC-Q100 qualified and PPAP capable. LM2575D2T-3.3G shares identical electrical specs, thermal characteristics, and pinout; it is widely used in non-safety-critical automotive subsystems (e.g., infotainment power, lighting control) where qualification is not mandated. Designers should verify end-equipment requirements before deployment.

What is the purpose of the ON/OFF pin (Pin 5) on LM2575D2T-3.3G?

Pin 5 (ON/OFF) provides TTL-compatible enable/disable control: driving it below 1.2 V (typically to GND) turns the regulator ON; pulling it above 2.2 V (e.g., to 3.3 V or 5 V) places LM2575D2T-3.3G in standby mode with ~80 µA quiescent current. This allows precise power sequencing, battery-saving sleep states, and system-level fault isolation. The pin is internally biased and requires no pull-up/down resistor-simplifying integration into microcontroller GPIO-controlled power trees.