onsemi NCP1117DT33

Overview

NCP1117DT33 from onsemi is a 3.3 V, 1.0 A low-dropout linear voltage regulator in DPAK (TO-252) package, featuring 1.2 V max dropout at 800 mA, ±1.0% output voltage accuracy, and integrated thermal shutdown, current limiting, and safe operating area protection. It operates with input voltages up to 20 V and requires no minimum load for regulation-ideal for point-of-load regulation in industrial power supplies and embedded controllers.

For engineers reviewing the NCP1117DT33 datasheet, pinout, applications, or equivalent options, key selection criteria include dropout voltage at full load, thermal performance with PCB copper heatsinking, output voltage tolerance over temperature, and compatibility with ceramic or tantalum output capacitors meeting ESR limits (33 mΩ–2.2 Ω).

Technical Context

The NCP1117DT33 implements a PNP pass transistor architecture enabling low dropout operation, with internal bandgap reference trimmed to ±1.0% and temperature-stable feedback loop ensuring ≤0.5% output variation over −40°C to +125°C ambient. Its fixed 3.3 V output eliminates external resistor networks required by adjustable variants.

Protection circuitry includes foldback current limiting activated above ~1.5 A, thermal shutdown triggered at ~175°C junction temperature, and safe operating area compensation preventing secondary breakdown during transient overload-enabling robust operation without external current-sense or thermal monitoring components.

Key Specifications

Pinout & Package

DPAK (TO-252-3) package with exposed metal tab thermally and electrically connected to Pin 2 (Output); case outline per ON Semiconductor Case 369C; 6.10 mm × 6.54 mm footprint; 2.28 mm height; lead-free (Pb-free) construction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM1117MPX-3.3/NOPB, NCP1117DT33 delivers full 1.0 A at lower dropout and supports higher input voltage (20 V), while NCV1117DT33T5G adds automotive qualification without sacrificing performance-making NCP1117DT33 optimal for cost-sensitive industrial designs needing robust 1 A capability.

Availability

NCP1117DT33 is available at Aetrix Electronics and suitable for industrial power supplies, embedded controller boards, and hard drive controller designs requiring stable component supply, long-term lifecycle support, and traceable Pb-free sourcing.

Supply support for NCP1117DT33 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, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The NCP1117 series was designed as a drop-in upgrade to legacy LM317-based circuits, delivering improved dropout, tighter voltage accuracy, and enhanced thermal protection for point-of-load regulation in space-constrained industrial and computing systems.

FAQ

What is the maximum input voltage rating for the NCP1117DT33?

The NCP1117DT33 has an absolute maximum input voltage rating of 20 V. However, for reliable operation at full 1.0 A output current, the input voltage must not exceed 12 V-exceeding this limit reduces the maximum allowable output current to prevent thermal overload, as specified in Note 3 of the datasheet.

Does the NCP1117DT33 require an external capacitor on the adjust pin?

No, the NCP1117DT33 is a fixed-output 3.3 V regulator and does not use the adjust pin as a functional terminal-it is internally connected to ground. Therefore, no external capacitor or resistor network is needed on Pin 1, unlike the adjustable NCP1117DTAG variant.

Can the NCP1117DT33 be used with ceramic output capacitors?

Yes, the NCP1117DT33 is stable with ceramic output capacitors of 4.7 µF to 10 µF, provided their equivalent series resistance (ESR) falls within the validated range of 33 mΩ to 2.2 Ω. This enables compact, low-ESR designs without compromising loop stability or transient response.

What thermal performance can be expected from the NCP1117DT33 in DPAK package?

In the DPAK (Case 369C) package, the NCP1117DT33 achieves a typical junction-to-ambient thermal resistance (R_JA) of 67°C/W with minimum PCB copper pad, improving to ~30°C/W with 2-inch² 2 oz. copper pour. Maximum power dissipation is internally limited but scales with ambient temperature per PD = (T_J(max) − T_A) / R_JA.

Is the NCP1117DT33 pin-compatible with older three-terminal regulators?

Yes, the NCP1117DT33 shares the same 3-pin DPAK pinout (Input–Output–Ground) and electrical behavior as industry-standard fixed-output regulators like the LM2931-3.3, enabling direct replacement in existing layouts-provided thermal design accounts for its higher 1.0 A capability and lower dropout characteristics.