onsemi NCV1117ST12T3

Overview

NCV1117ST12T3 from onsemi is an automotive-grade, low-dropout linear voltage regulator delivering a fixed 12 V output at up to 1.0 A, with maximum dropout voltage of 1.20 V at 800 mA over temperature, ±1.0% output voltage accuracy, and integrated thermal shutdown, current limiting, and safe operating area protection. It is used in battery-charged systems and hard drive controllers requiring stable 12 V rail regulation under varying input conditions.

For engineers reviewing the NCV1117ST12T3 datasheet, pinout, applications, or equivalent options, key selection criteria include dropout performance at 800 mA, thermal behavior in SOT−223 package, load/line regulation specs (≤16 mV / ≤1.0%), ripple rejection (54 dB at 12 V), and AEC−Q100 qualification for automotive deployment.

Technical Context

The NCV1117ST12T3 employs a PNP pass transistor architecture enabling low dropout operation down to 1.07 V at 800 mA, with internal bandgap reference trimmed to ±1.0% across −40°C to +125°C ambient. Its control loop maintains regulation without minimum load requirement and supports input voltages up to 20 V.

Protection circuitry includes foldback current limiting activated above ~1.5 A, thermal shutdown triggering near 175°C junction temperature, and safe operating area compensation to prevent secondary breakdown during transient overload. The device operates in continuous conduction mode and requires no external compensation components when using ≥4.7 µF output capacitance with ESR between 33 mΩ and 2.2 Ω.

Key Specifications

Pinout & Package

SOT−223 package (Case 318H), surface-mount, with exposed metal tab thermally connected to Pin 2 (Output) for PCB heatsinking. Dimensions: 6.7 mm × 3.7 mm × 1.8 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV1117-12CDCYR and LD1086V12, the NCV1117ST12T3 uniquely combines AEC−Q100 compliance, SOT−223 surface-mount packaging, and 1.20 V dropout at full load-making it the sole drop-in solution for automotive 12 V point-of-load regulation where qualification, size, and efficiency are jointly constrained.

Availability

NCV1117ST12T3 is available at Aetrix Electronics and suitable for automotive body electronics, industrial storage controllers, and battery-powered instrumentation requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for NCV1117ST12T3 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 sensor solutions for automotive, industrial, and cloud infrastructure markets.

The NCV1117 series belongs to onsemi's automotive-qualified linear regulator product line, designed specifically for safety-critical and mission-reliability applications demanding AEC−Q100 compliance, extended temperature operation, and robust thermal protection.

FAQ

What is the maximum input voltage rating for the NCV1117ST12T3?

The NCV1117ST12T3 has a maximum input voltage rating of 20 V, as specified in the Absolute Maximum Ratings table. Operation above this voltage risks permanent damage. For reliable 12 V output regulation, the minimum valid input is 13.5 V (Vout + dropout), and the device must be derated to ≤1.0 A when Vin exceeds 12 V per datasheet Note 6.

Does the NCV1117ST12T3 require an external capacitor on the output pin?

Yes, the NCV1117ST12T3 requires a minimum 4.7 µF output capacitor with ESR between 33 mΩ and 2.2 Ω for stability. Ceramic, tantalum, or aluminum electrolytic types are acceptable. The datasheet confirms instability risk without proper Cout, and recommends 10 µF for optimal transient response and noise reduction in the NCV1117ST12T3 design.

Is the NCV1117ST12T3 pin-compatible with the LM317?

No-the NCV1117ST12T3 is not pin-compatible with the LM317. While the NCP1117 family (non-automotive) is stated to be pin-compatible with LM317 derivatives, the NCV1117ST12T3 uses a fixed-output SOT−223 pinout (GND–OUT–IN), whereas the LM317 is adjustable and uses ADJ–OUT–IN pin order. Substituting NCV1117ST12T3 for LM317 requires PCB layout changes.

What thermal performance can be expected from the NCV1117ST12T3 in SOT−223 package?

In the SOT−223 package (Case 318H), the NCV1117ST12T3 has a typical junction-to-ambient thermal resistance (R_JA) of 160°C/W on minimal PCB copper, improving to ~60°C/W with 2 oz. copper pad extensions per Figure 21. At 1.0 A load and 13.5 V input, power dissipation is ~1.5 W; thus, ambient temperature must remain ≤75°C to avoid thermal shutdown activation.

How does the NCV1117ST12T3 handle short-circuit conditions?

The NCV1117ST12T3 features foldback current limiting and thermal shutdown for short-circuit protection. Under sustained output short, output current drops to ~200–300 mA (per Figure 7), and junction temperature rises until thermal shutdown activates (~175°C). Once cooled to ~150°C, the device auto-restarts. This cycle prevents destruction but is not intended for continuous short-circuit operation.