onsemi NCP5663DS18R4G

Overview

NCP5663DS18R4G from onsemi is a fixed-output, 1.8 V, 3.0 A ultra-low-dropout linear regulator in D2PAK package, featuring 1.0 V typical dropout at full load, 28 µV_rms output noise without bypass capacitor, and integrated Enable and Error Flag functions-designed for post-regulation in high-current ASIC and server power supplies.

For engineers reviewing the NCP5663DS18R4G datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed 1.8 V ±1% accuracy over −40°C to +150°C, thermal shutdown at 160°C, 0.03% line regulation, and compatibility with low-ESR ceramic output capacitors ≥10 µF.

Technical Context

The NCP5663DS18R4G implements a bipolar-based LDO architecture with a 0.9 V internal reference, enabling stable 1.8 V output via trimmed resistor network. Its ultra-fast transient response (settling within 1–3 µs) is enabled by high-gain error amplifier and optimized compensation for 10–150 µF output capacitance range.

It integrates dual protection: current limiting clamps peak output at 4.5 A and thermal shutdown activates at 160°C junction temperature. The Error Flag pin asserts logic-low when output falls below 91–97% of nominal 1.8 V, requiring external 100 kΩ pull-up for operation.

Key Specifications

Pinout & Package

D2PAK (Case 936A), thermally enhanced 5-pin surface-mount package with exposed tab connected to ground for optimal heat dissipation (R_θJC = 5.0°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A8300RGRT and MCP1826T-1802E/OT, the NCP5663DS18R4G uniquely combines Error Flag signaling, 28 µV_rms noise without bypass cap, and D2PAK thermal robustness-making it optimal for high-reliability, high-current post-regulation where fault visibility and thermal margin are design priorities.

Availability

NCP5663DS18R4G is available at Aetrix Electronics and suitable for server VRM post-regulation, ASIC core power supplies, and networking equipment point-of-load applications requiring stable component supply, long-term lifecycle support, and Pb-free compliance.

Supply support for NCP5663DS18R4G 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 manufacturer specializing in energy-efficient power management, analog, and sensor solutions for automotive, industrial, and cloud infrastructure markets.

The NCP5663DS18R4G belongs to onsemi's high-current LDO family designed specifically for demanding post-regulation tasks in servers, ASICs, and networking gear-where ultra-fast transient response, thermal resilience, and integrated monitoring are essential.

FAQ

What is the maximum input voltage rating for the NCP5663DS18R4G?

The NCP5663DS18R4G has an absolute maximum input voltage rating of 18 V. However, its recommended operating input voltage range is 2.0 V to 9.0 V per the Electrical Characteristics table. Exceeding 9.0 V may compromise output accuracy and thermal performance, even if below the 18 V absolute limit. Always maintain Vin − Vout ≥ 1.5 V for guaranteed specifications.

Does the NCP5663DS18R4G require an external bypass capacitor to achieve its specified 28 µV_rms noise performance?

No, the NCP5663DS18R4G achieves 28 µV_rms output noise without any external bypass capacitor. This is explicitly stated in the datasheet Features section and confirmed in the Electrical Characteristics table for both adjustable and fixed-output versions. Adding a bypass capacitor does not improve noise further and is unnecessary for meeting the rated specification.

How does the Error Flag function on the NCP5663DS18R4G behave during startup and fault conditions?

The Error Flag on the NCP5663DS18R4G is an open-collector output that remains high-impedance until Vout reaches regulation. Once enabled, it pulls low when Vout drops below 91–97% of 1.8 V (i.e., 1.64–1.75 V). During startup, it stays high until regulation is achieved; during overcurrent or thermal shutdown, it asserts low only if Vout collapses outside that window-not during brief transients (blanking time is 50 µs).

Can the NCP5663DS18R4G operate with a 10 µF output capacitor, and what are the stability implications?

Yes, the NCP5663DS18R4G is stable with output capacitance as low as 10 µF, as verified in Figures 15 and 16 of the datasheet. For guaranteed stability across 10 mA–3.0 A load range, use 33–150 µF ceramic capacitors with 50–300 mΩ ESR. A 10 µF capacitor is acceptable for space-constrained designs but may reduce phase margin marginally-layout must minimize trace inductance.

Is the NCP5663DS18R4G pin-compatible with other members of the NCP5663 family, such as the adjustable version NCP5663DSADJR4G?

No, the NCP5663DS18R4G is not pin-compatible with the adjustable version NCP5663DSADJR4G. While both use the same D2PAK package and share pins 1–4 (Enable, Vin, Ground, Vout), Pin 5 serves as Error Flag on the fixed-output NCP5663DS18R4G but as Adjust on the adjustable version-requiring different external circuitry and PCB layout. Interchanging them without redesign will cause functional failure.