onsemi NCP4671DSN09T1G

Overview

NCP4671DSN09T1G from onsemi is a 400 mA dual-rail ultra-low dropout linear regulator with fixed 0.9 V output, designed for low-voltage power domains in portable electronics. It features a separate VBIAS input (2.4–5.25 V) and ultra-low dropout of 180 mV at 400 mA, enabling operation from as low as 1.0 V input (VOUT + 0.1 V). Its auto-discharge function and ±15 mV output accuracy support precision biasing of modern SoCs and RF ICs.

For engineers reviewing the NCP4671DSN09T1G datasheet, pinout, applications, or equivalent options, key selection criteria include its dual-rail architecture, 0.9 V fixed output, SOT-23-5 package, 28 µA quiescent current, and integrated output discharger - critical for fast power sequencing in battery-powered systems.

Technical Context

The NCP4671DSN09T1G implements a CMOS-based dual-rail LDO architecture: VIN supplies the pass element while VBIAS independently powers the control circuitry, decoupling regulation stability from input rail noise. This enables stable 0.9 V output even when VIN drops to 1.0 V, with minimal PSRR degradation from VBIAS ripple (50 dB at 1 kHz).

It integrates CE-controlled enable logic, thermal shutdown, current foldback protection (120 mA typical), and an internal N-channel discharge transistor activated during disable mode - eliminating external bleed resistors and reducing system wake-up latency in portable devices.

Key Specifications

Pinout & Package

SOT-23-5 package (Case 1212), 2.7 mm × 2.5 mm × 1.3 mm body, Pb-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6219B092MR-G and RT9013-09GB, the NCP4671DSN09T1G uniquely delivers dual-rail noise isolation, guaranteed 0.9 V ±15 mV accuracy, and integrated auto-discharge - making it the only option among the three qualified for high-reliability, low-latency power sequencing in portable SoC platforms.

Availability

NCP4671DSN09T1G is available at Aetrix Electronics and suitable for mobile phone baseband, wearable sensor hub, and portable camera ISP applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for NCP4671DSN09T1G 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, sensing, and connectivity solutions for automotive, industrial, and consumer markets.

The NCP4671DSN09T1G belongs to onsemi's high-performance LDO family targeting ultra-low-voltage, ultra-low-power portable electronics - engineered to replace legacy single-rail regulators in next-generation battery-constrained devices.

FAQ

What is the minimum input voltage required for NCP4671DSN09T1G to regulate 0.9 V output?

The NCP4671DSN09T1G requires VIN ≥ VOUT + 0.1 V = 1.0 V when VOUT ≥ 0.8 V. This ultra-low dropout enables operation from partially discharged Li-ion cells down to 1.0 V, extending usable battery capacity. The device remains functional but may not maintain regulation if VIN falls below this threshold.

Does NCP4671DSN09T1G require external capacitors, and what values are recommended?

Yes, NCP4671DSN09T1G requires ceramic decoupling: 1.0 µF on VIN, 1.0 µF on VBIAS, and ≥2.2 µF on VOUT. These values ensure stability, optimize line/load transient response, and prevent oscillation. Tantalum capacitors are discouraged due to ESR-related instability risks.

How does the VBIAS pin function in NCP4671DSN09T1G, and what happens if it's omitted?

The VBIAS pin supplies independent power to the NCP4671DSN09T1G's control circuitry (error amplifier, reference, CE logic), isolating it from VIN noise. If unconnected or under-volted (<2.4 V), regulation fails - VOUT collapses regardless of VIN. VBIAS must be ≥0.9 V + 1.6 V = 2.5 V per datasheet specification.

What is the purpose of the auto-discharge feature in NCP4671DSN09T1G?

The auto-discharge feature activates an internal N-channel FET between VOUT and GND when CE is low, rapidly discharging the output capacitor. This prevents floating voltages, reduces wake-up latency, and avoids unintended operation of downstream logic - eliminating the need for external bleed resistors in space-constrained designs.

Can NCP4671DSN09T1G be used with a 3.3 V VBIAS and 1.05 V VIN to deliver 0.9 V?

Yes - the NCP4671DSN09T1G is explicitly rated for VBIAS = 3.3 V and VIN = VOUT + 0.1 V = 1.0 V. At 1.05 V VIN, it delivers 0.9 V at up to 400 mA with ~180 mV dropout. This configuration is validated in Figures 45–47 and Table 4 of the datasheet for 0.9 V versions.