onsemi MC33269DG

Overview

MC33269DG from onsemi is a low-dropout (LDO) positive voltage regulator in SO-8 package, delivering up to 800 mA output current with 1.0 V dropout at 500 mA and ±1.0% output voltage tolerance. It integrates thermal shutdown and short-circuit protection, and supports adjustable or fixed 3.3 V, 5.0 V, and 12 V outputs. It is widely used in automotive body control modules requiring stable 5 V rail under low-input-voltage conditions.

For engineers reviewing the MC33269DG datasheet, pinout, applications, or equivalent options, key selection criteria include dropout voltage at full load, thermal resistance in SO-8 (JA = 160°C/W), output trim accuracy (±1.0%), and compatibility with 10 µF/ESR <10 Ω output capacitors for stability across −40°C to +125°C ambient.

Technical Context

The MC33269DG employs a composite PNP–NPN pass transistor architecture enabling 1.0 V dropout while maintaining regulation down to VIN − VOUT = 1.25 V at 800 mA. Its internal reference is trimmed to 1.25 V (±1.2%) and remains stable over line, load, and temperature (±0.1% typical drift).

Protection circuitry includes foldback current limiting triggered at ≥800 mA and thermal shutdown activating at TJ ≈ 170°C with no hysteresis-requiring external heatsinking for sustained >500 mA operation in SO-8 at TA > 50°C.

Key Specifications

Pinout & Package

MC33269DG uses the SO-8 (Case 751) surface-mount package with exposed thermal pad connected to Pin 2 (VOUT). The device has three active terminals and five NC pins; thermal performance depends critically on soldering the exposed pad to a minimum 25 mm² copper area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2940CT-5.0/NOPB and NCP1117ST50T3G, MC33269DG offers superior dropout performance in SO-8 form factor and tighter initial tolerance, making it optimal for automotive and high-reliability embedded systems where input voltage sag and precision regulation are critical.

Availability

MC33269DG is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC power rails, medical front-end signal chains, and point-of-sale terminal power management requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for MC33269DG 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, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The MC33269 series was designed for low-input-voltage, medium-current regulation in harsh environments-targeting automotive sub-systems, industrial controls, and medical devices needing robust thermal and fault protection.

FAQ

What is the maximum input voltage rating for MC33269DG?

The MC33269DG has an absolute maximum input voltage (VIN) rating of 20 V. Exceeding this value risks permanent damage. For the 12 V version (MC33269DG-12), VIN − VOUT is further limited to 8.0 V maximum due to internal design constraints-so VIN must not exceed 20 V and VOUT + 8.0 V simultaneously. Always observe both limits in system design.

Does MC33269DG require an input bypass capacitor?

While not required for stability, MC33269DG benefits from a 0.33 µF or larger input bypass capacitor placed directly across VIN and GND. This improves transient response and reduces sensitivity to high-frequency input impedance-especially important when the regulator is fed via long traces from a DC/DC converter or noisy power bus. Ceramic or low-ESR tantalum types are recommended.

Can MC33269DG be used in adjustable-output configuration?

Yes, MC33269DG supports adjustable output using the GND/Adj pin (Pin 1). With R1 connected between VOUT and Adj, and R2 between Adj and GND, output voltage is set by VOUT = 1.25 × (1 + R2/R1) + I_Adj×R2. Since I_Adj ≤ 120 nA, its contribution is negligible if R2 ≤ 10 kΩ. Minimum load current is 0 mA for adjustable mode.

What thermal considerations apply to MC33269DG in SO-8 package?

MC33269DG in SO-8 has θ_JA = 160°C/W (free-air), but this drops significantly with PCB copper area. To sustain 500 mA at TA = 70°C, a minimum 25 mm² 2 oz. copper pad under the exposed thermal pad is required. Without adequate copper, junction temperature exceeds 150°C rapidly-triggering thermal shutdown. Figure 8 in the datasheet provides exact copper-length vs. power-dissipation curves.

Is MC33269DG pin-compatible with other regulators like LM2940 or NCP1117?

No, MC33269DG is not pin-compatible with LM2940 (TO-220, 3-pin) or NCP1117 (TO-220/SOT-223/SO-8 but different pinout). In SO-8, MC33269DG uses Pin 1 = GND/Adj, Pin 2 = VOUT, Pin 3 = VIN, whereas NCP1117ST50T3G uses Pin 1 = GND, Pin 2 = VOUT, Pin 3 = VIN-making direct replacement impossible without PCB redesign. Always verify pin mapping before substitution.