onsemi NCP1117LPST25T3G

Overview

NCP1117LPST25T3G from onsemi is a 2.5 V fixed-output, low-dropout linear voltage regulator delivering up to 1.0 A output current with 1.3 V typical dropout at full load, internal thermal shutdown and current limiting, and optimized for post-regulation in consumer power supplies such as set-top boxes and game consoles.

For engineers reviewing the NCP1117LPST25T3G datasheet, pinout, applications, or equivalent options, key selection criteria include dropout voltage at 1 A, quiescent current (700 µA max), output voltage accuracy (±2% over temperature), thermal shutdown threshold (165 °C), and SOT-223 package thermal performance.

Technical Context

The NCP1117LPST25T3G implements a bandgap-referenced error amplifier driving a PNP pass transistor, enabling stable regulation with minimal external components. Its architecture supports operation from 4 V to 18 V input while maintaining 2.5 V ±2% output across 0–125 °C ambient and 10 mA–1 A load range.

Internal protection includes foldback current limiting (1.1 A min) and thermal shutdown with 10 °C hysteresis. The device requires no minimum load for stability and achieves 60 dB ripple rejection at 120 Hz with 25 µF tantalum output capacitance.

Key Specifications

Pinout & Package

The NCP1117LPST25T3G is housed in a Pb-free SOT-223 package (Case 318H) with heatsink tab electrically connected to Pin 2 (Vout). The exposed metal tab enables PCB copper to act as primary heatsink, reducing R_JA to 108 °C/W on standard 1 oz FR4.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MIC2925-2.5WS and TLV70225DBVR, the NCP1117LPST25T3G uniquely balances 1 A output, 1.3 V dropout, and SOT-223 thermal performance-making it optimal for cost-sensitive, high-volume consumer power rails requiring robust thermal protection and no minimum load.

Availability

NCP1117LPST25T3G is available at Aetrix Electronics and suitable for set-top box power rails, hard drive controller logic supplies, game console peripheral interfaces, and consumer audio DAC supplies requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for NCP1117LPST25T3G 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 consumer markets.

The NCP1117LP series was designed specifically for high-volume consumer electronics requiring low-quiescent-current, thermally robust LDO regulation in compact SOT-223 packaging-targeting TV, set-top box, and gaming applications.

FAQ

What is the maximum input voltage rating for the NCP1117LPST25T3G?

The NCP1117LPST25T3G has a maximum DC input voltage rating of 18 V, as specified in the Absolute Maximum Ratings table. Operation above this voltage risks permanent damage. For reliable 2.5 V output, input must remain ≥3.8 V (2.5 V + 1.3 V dropout) across all load and temperature conditions.

Does the NCP1117LPST25T3G require an external capacitor on the output pin?

Yes-the NCP1117LPST25T3G requires a minimum 4.7 µF output capacitor with ESR between 20 mΩ and 20 Ω for stability. A 10 µF tantalum or ceramic capacitor is recommended. Without it, the regulator may oscillate or fail to regulate under load transients.

Is the NCP1117LPST25T3G pin-compatible with the standard NCP1117 series?

Yes-the NCP1117LPST25T3G uses the same SOT-223 pinout (GND-Vout-Vin) and footprint as the legacy NCP1117, enabling drop-in replacement in existing designs. However, its quiescent current is 10× lower, and dropout voltage is slightly improved.

What thermal derating applies to the NCP1117LPST25T3G in a standard PCB layout?

On a 100 mm × 100 mm PCB with 1 oz copper, the NCP1117LPST25T3G has R_JA = 108 °C/W. At 25 °C ambient, maximum continuous power dissipation is ~1.16 W before reaching 150 °C junction limit-corresponding to ~0.46 A at 2.5 V output with 12 V input.

Can the NCP1117LPST25T3G be used in adjustable-output configurations?

No-the NCP1117LPST25T3G is a fixed 2.5 V output variant. Adjustable versions are designated NCP1117LPSTADT3G (SOT-223) or NCP1117LPDTADJRKG (DPAK). The ST25T3G suffix confirms fixed 2.5 V output and SOT-223 packaging.