onsemi MC33275DT-3.3

Overview

MC33275DT-3.3 from onsemi is a micropower low-dropout linear voltage regulator delivering a fixed 3.3 V output with ±2% tolerance over −40°C to +125°C, supporting up to 300 mA load current, featuring 260 mV dropout at full load and internal thermal/current limiting protection. It is designed for battery-powered portable electronics requiring extended runtime and stable low-noise supply.

For engineers reviewing the MC33275DT-3.3 datasheet, pinout, applications, or equivalent options, key selection considerations include dropout performance at 300 mA, thermal shutdown threshold at 150°C, stability with ≥0.33 µF output capacitance, and DPAK-3 package thermal resistance (92°C/W junction-to-air).

Technical Context

The MC33275DT-3.3 employs a PNP pass transistor architecture enabling ultra-low dropout-25 mV at 10 mA and 260 mV at 300 mA-while maintaining tight line regulation (≤10 mV) and load regulation (≤25 mV). Its internal reference is trimmed to 1.23 V, and feedback network sets nominal output to 3.30 V.

Thermal protection activates at 150°C with no hysteresis, causing output oscillation until junction cools; current limiting caps output at ~450 mA. Quiescent current is 125 µA typical in normal operation and rises to 1500–2000 µA in saturation mode when input drops below V_OUT − 0.5 V.

Key Specifications

Pinout & Package

DPAK-3 (Case 369C) surface-mount package: thermally enhanced with exposed drain pad (Pin 3) tied to GND internally; 6.10 × 6.54 × 2.28 mm footprint, 2.29 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout voltage regulator applications.

Compared with MC33275DT-3.3, the NCV33275ST-3.3T3G offers identical regulation and protection in a smaller thermal package, while the MCP1700T-3302E/MB trades off current capability and dropout for nanoamp quiescent draw-making each suitable for distinct power budget and thermal design priorities.

Availability

MC33275DT-3.3 is available at Aetrix Electronics and suitable for battery-powered consumer products, handheld instruments, and industrial edge devices requiring stable component supply with automotive-grade traceability options.

Supply support for MC33275DT-3.3 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 MC33275 series belongs to onsemi's precision linear regulator product line, engineered specifically for portable and battery-operated systems where low dropout, micropower operation, and robust thermal protection are mandatory.

FAQ

What is the minimum input voltage required for MC33275DT-3.3 to maintain regulation at 300 mA?

The MC33275DT-3.3 requires a minimum input voltage of 3.56 V (3.3 V + 260 mV dropout) to sustain 300 mA output current while maintaining regulation. Below this, output voltage collapses; datasheet Figure 7 confirms 260 mV dropout at 300 mA across temperature.

Can MC33275DT-3.3 operate with a 0.22 µF output capacitor?

No-MC33275DT-3.3 requires ≥0.33 µF output capacitance for stability with 3.3 V output. The datasheet explicitly states 0.22 µF is only sufficient for 5.0 V versions; using 0.22 µF risks oscillation and poor transient response.

Does MC33275DT-3.3 have reverse polarity or reverse current protection?

No-the MC33275DT-3.3 lacks built-in reverse polarity or reverse current protection. If input voltage can fall below output (e.g., during shutdown), an external Schottky diode between VIN and VOUT is recommended to prevent backfeed and potential damage.

Is MC33275DT-3.3 compatible with ceramic output capacitors?

Yes-MC33275DT-3.3 is stable with ceramic, tantalum, or aluminum electrolytic output capacitors ≥0.33 µF. Ceramic types are preferred for low ESR and compact size; Figure 16 shows stable ESR range down to 0.1 Ω at 300 mA.

How does thermal shutdown behave in MC33275DT-3.3 under sustained overload?

MC33275DT-3.3 thermal shutdown activates at 150°C with no hysteresis, causing output to cycle on/off as junction temperature crosses threshold. This "oscillatory shutdown" protects the die but requires adequate PCB copper (Figure 18) or heatsinking to avoid functional interruption.