onsemi NCP4671DMX12TCG

Overview

NCP4671DMX12TCG from onsemi is a 400 mA dual-rail ultra-low dropout linear regulator with fixed 1.2 V output, designed for low-voltage power rails in portable electronics. It features a separate VBIAS input (2.4–5.25 V), supports VIN as low as 1.3 V (VOUT + 0.1 V), delivers ±15 mV output accuracy at 25°C, and achieves 180 mV typical dropout at 400 mA - enabling operation from near-threshold input voltages in battery-powered systems.

For engineers reviewing the NCP4671DMX12TCG datasheet, pinout, applications, or equivalent options, key selection considerations include its XDFN6 package (1.2 × 1.2 × 0.4 mm), auto-discharge capability, bias-input separation for PSRR optimization, and thermal performance (R_JA = 250°C/W) in space-constrained designs.

Technical Context

The NCP4671DMX12TCG implements a dual-rail architecture where VBIAS powers the control circuitry independently of VIN, decoupling regulation stability from input rail noise and enabling ultra-low dropout operation. This architecture allows stable 1.2 V output even when VIN drops to 1.3 V while maintaining high PSRR (80 dB at 1 kHz for VIN ripple, 50 dB for VBIAS ripple).

It integrates CE-controlled enable logic with internal pull-down, supports fast load transients via low-output-impedance design, and includes current-foldback protection (120 mA typ.) and UVLO on VIN. The D-version variant adds an internal VOUT-to-GND discharge transistor activated during disable mode.

Key Specifications

Pinout & Package

XDFN6 package (1.2 mm × 1.2 mm × 0.4 mm, wettable flank), Pb-free, 6-terminal surface-mount with exposed thermal pad.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B122MR-G and AP7361-12SG-7, the NCP4671DMX12TCG uniquely combines ultra-low dropout (180 mV), dual-rail PSRR optimization, and integrated auto-discharge in a 1.2 mm² XDFN6 package - making it optimal for space-constrained, noise-sensitive, battery-critical applications where input is sourced from a DC/DC converter.

Availability

NCP4671DMX12TCG is available at Aetrix Electronics and suitable for portable medical devices, wearable electronics, and industrial handheld scanners requiring stable component supply, long-term lifecycle support, and Pb-free compliance.

Supply support for NCP4671DMX12TCG 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 focused on energy-efficient electronics, with leadership in power management, analog, and sensor technologies.

The NCP4671DMX12TCG belongs to onsemi's ultra-low-dropout LDO family engineered for battery-powered portable equipment requiring high accuracy, low IQ, and robust transient response in sub-2 mm² packages.

FAQ

What is the minimum input voltage required for NCP4671DMX12TCG to regulate 1.2 V output?

The NCP4671DMX12TCG requires VIN ≥ VOUT + 0.1 V = 1.3 V when VOUT ≥ 0.8 V, per datasheet Section "Operating Power Input Voltage". At 400 mA load and 25°C, dropout is 180 mV typical, so 1.3 V input sustains regulation. Below 1.3 V, output collapses linearly per Figure 33–35.

Does NCP4671DMX12TCG require external capacitors, and what values are recommended?

Yes: 1 µF ceramic capacitors on VIN and VBIAS (placed ≤2 mm from pins), and ≥2.2 µF ceramic on VOUT (also ≤2 mm from pin). These values ensure stability, line/load transient response, and PSRR performance per Application Information (page 19). Tantalum caps are discouraged due to ESR-related oscillation risk.

How does the auto-discharge feature of NCP4671DMX12TCG operate?

The NCP4671DMX12TCG (D-version) activates an internal NMOS transistor between VOUT and GND when CE is pulled low, discharging the output capacitor rapidly. This prevents residual voltage from holding downstream logic in undefined states during power-down - critical for reliable system reset sequencing.

Can NCP4671DMX12TCG be used with a 1.8 V bias supply?

No. For VOUT = 1.2 V ≥ 0.8 V, VBIAS must be ≥ VOUT + 1.6 V = 2.8 V per datasheet Table "Bias Supply Voltage Range". A 1.8 V bias violates this requirement and will cause improper regulation or failure to enable - use ≥2.8 V (e.g., 3.3 V or 3.6 V).

What is the thermal performance of NCP4671DMX12TCG in its XDFN6 package?

The NCP4671DMX12TCG has R_JA = 250°C/W in the XDFN6 package (page 3). At 400 mA and 180 mV dropout, power dissipation is 72 mW, resulting in ~18°C junction rise above ambient. No heatsink is needed for typical handheld operation, but thermal relief via PCB copper pour is recommended for sustained high-load conditions.