onsemi NCP5661MN30T2G

Overview

NCP5661MN30T2G from onsemi is a fixed-output, 3.0 V, 1.0 A ultra-low-dropout linear regulator in a thermally robust DFN6 3×3.3 mm package. It delivers ultra-fast transient response (1–3 µs settling), low ground current (≤3.0 mA at 1.0 A), and 26 µV_rms output noise without bypass capacitor - ideal for post-regulation in high-performance ASIC and server power supplies.

For engineers reviewing the NCP5661MN30T2G datasheet, pinout, applications, or equivalent options, key selection criteria include dropout voltage ≤1.3 V at 1.0 A, ±1% output accuracy over −40°C to +125°C, Error Flag functionality with 88% V_OUT threshold, and thermal shutdown at 160°C - all verified per onsemi's Rev. 20 datasheet.

Technical Context

The NCP5661MN30T2G integrates a 0.9 V internal reference and precision error amplifier to regulate 3.0 V output with load regulation of ≤0.2% across 10 mA–1.0 A. Its architecture maintains low ground current independent of load and achieves >65 dB ripple rejection at 1 kHz, enabling stable operation in noisy switching supply environments.

It features active Enable control (logic-high threshold ≥1.3 V), an open-drain Error Flag output (active-low at ≤88% V_OUT, blanked for 50 µs), and dual protection: current limiting (1.5 A typical) and thermal shutdown (160°C). The DFN6 package uses EPAD-connected GND for optimal thermal performance (R_θJL = 18°C/W).

Key Specifications

Pinout & Package

Package: DFN6 3.0×3.3 mm, 0.95 mm pitch, exposed thermal pad (EPAD) connected to Pin 3 (GND). Thermal resistance R_θJL = 18°C/W with 1 in² copper area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A4700RGWR and MCP1826T-3002E/DB, the NCP5661MN30T2G uniquely combines ultra-low noise, integrated Error Flag, and load-independent ground current - making it optimal for high-reliability, space-constrained systems requiring autonomous fault detection and minimal quiescent loss.

Availability

NCP5661MN30T2G is available at Aetrix Electronics and suitable for server VRM post-regulation, ASIC core power supplies, and networking equipment requiring stable component supply with automotive-grade reliability (AEC-Q100 qualified variant available as NCV5661MN30T2G).

Supply support for NCP5661MN30T2G 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, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and IoT applications.

The NCP5661 series was designed specifically for high-current, low-noise linear regulation in demanding computing and communications infrastructure - emphasizing ultra-fast transient response, thermal robustness, and integrated system-monitoring features like Error Flag.

FAQ

What is the maximum input voltage rating for the NCP5661MN30T2G?

The NCP5661MN30T2G has an absolute maximum input voltage (V_IN) of 18 V, but its recommended operating range is 2.0 V to 9.0 V per the Electrical Characteristics table. Operation above 9.0 V is not characterized and may compromise long-term reliability or parametric performance. Always maintain V_IN − V_OUT ≥ 1.5 V for guaranteed dropout and PSRR specifications. The NCP5661MN30T2G must never be subjected to input voltages exceeding 18 V, even transiently.

Does the NCP5661MN30T2G require an external bypass capacitor for low-noise operation?

No, the NCP5661MN30T2G delivers 26 µV_rms output noise (10 Hz–100 kHz) without any external bypass capacitor - a key design advantage confirmed in the Electrical Characteristics table and Application Information section. This eliminates board space and BOM cost associated with traditional 1–10 µF ceramic bypass caps. However, a minimum 10 µF output capacitor (low-ESR ceramic or polymer) remains mandatory for loop stability, as specified in the Output Capacitor section of the datasheet.

How does the Error Flag function on the NCP5661MN30T2G, and what external components are needed?

The NCP5661MN30T2G Error Flag (Pin 5) is an open-drain output that pulls low when V_OUT falls to ≤88% of nominal (≤2.64 V for 3.0 V output), with a 50 µs blanking time to ignore transient dips. It requires an external 100 kΩ pull-up resistor to V_IN (Pin 2) to generate a logic-high signal during normal operation. No pull-up is needed if the flag is unused. The NCP5661MN30T2G Error Flag leakage is ≤1.0 µA, ensuring minimal current draw in monitoring circuits.

What thermal performance can be expected from the NCP5661MN30T2G in a standard PCB layout?

In a standard layout with 1 in² of 1 oz copper connected to the EPAD (Pin 6), the NCP5661MN30T2G achieves R_θJL = 18°C/W, allowing it to sustain 1.0 A output at ambient temperatures up to +85°C without forced air. With 0.26 in² copper (minimum pad), R_θJA = 82°C/W limits continuous 1.0 A operation to ~+55°C ambient. Derating is required above 125°C junction temperature; thermal shutdown activates at 160°C. The NCP5661MN30T2G thermal characteristics are fully documented in Table 2 (Thermal Characteristics, DFN6).

Is the NCP5661MN30T2G pin-compatible with other variants in the NCP5661 family?

Yes, all DFN6-packaged NCP5661 variants - including NCP5661MN15T2G (1.5 V), NCP5661MN28T2G (2.8 V), and NCP5661MN33T2G (3.3 V) - share identical pinout, footprint, and thermal pad configuration. The NCP5661MN30T2G can be substituted within the same DFN6 footprint without PCB changes, provided the system design accommodates the specific fixed output voltage and verifies compatibility of Enable threshold and Error Flag behavior across variants.