onsemi NCP145AMX120TCG

Overview

NCP145AMX120TCG from onsemi is a 500 mA very low dropout (VLDO) linear voltage regulator with NMOS pass transistor and separate bias rail (VBIAS), delivering a fixed 1.20 V output. It operates from 1.0 V to 5.5 V input and requires ≥2.8 V bias supply, achieving ±1.5% output accuracy over temperature and ultra-low 140 mV dropout at full load-ideal for post-regulation in space-constrained, noise-sensitive portable systems.

For engineers reviewing the NCP145AMX120TCG datasheet, pinout, applications, or equivalent options, key selection criteria include its dual-rail architecture (VIN/VBIAS), active output discharge capability, 210 µs turn-on time, stability with 2.2 µF ceramic output capacitor, and XDFN4 1.2 mm × 1.2 mm package footprint.

Technical Context

The NCP145AMX120TCG employs an NMOS pass transistor powered by a dedicated VBIAS rail, decoupling control circuitry from VIN to enable stable regulation at ultra-low input-to-output differentials. Its internal architecture includes undervoltage lockout on VBIAS, thermal shutdown at 160°C, and logic-level enable with hysteresis.

It features active output discharge (enabled only in 'A' and 'C' variants), soft-start via controlled slew rate (17 mV/µs), and PSRR of 70 dB (VIN→VOUT) and 80 dB (VBIAS→VOUT) at 1 kHz-critical for powering noise-sensitive analog or RF circuitry downstream of switching regulators.

Key Specifications

Pinout & Package

XDFN4 package: 1.2 mm × 1.2 mm × 0.4 mm, 5-pin exposed-pad layout (Case 711BC), optimized for high-density portable PCBs with thermal performance of 170°C/W junction-to-air.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP145CMX120TCG, the NCP145AMX120TCG offers faster startup and tighter monotonic control; versus TPL74073PWR, it delivers higher current, lower dropout, and bias-rail flexibility-making it uniquely suited for high-performance portable post-regulation where noise, efficiency, and sequencing matter.

Availability

NCP145AMX120TCG is available at Aetrix Electronics and suitable for smartphone power management, tablet memory interface regulation, and wearable sensor hub supply requiring stable component supply, consistent parametric performance, and RoHS-compliant packaging.

Supply support for NCP145AMX120TCG 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, delivering silicon solutions for automotive, industrial, cloud, and portable markets.

The NCP145AMX120TCG belongs to onsemi's precision low-dropout regulator product line, engineered specifically for noise-sensitive, space-constrained battery-powered applications demanding dual-rail operation and fast, controlled power sequencing.

FAQ

What is the minimum required VBIAS voltage for reliable operation of the NCP145AMX120TCG?

The NCP145AMX120TCG requires a minimum VBIAS of 2.8 V, defined as VOUT(NOM) + 1.6 V (1.20 V + 1.6 V). This ensures internal control circuitry remains powered and UVLO does not trigger. Operation below this threshold may cause erratic enable behavior or failure to regulate, as confirmed in the Electrical Characteristics table for the NCP145xMX120TCG variant.

Does the NCP145AMX120TCG support active output discharge, and how does it function?

Yes, the NCP145AMX120TCG includes active output discharge. When the EN pin is driven ≤0.4 V, an internal 150 Ω pull-down resistor connects OUT to GND, discharging external output capacitance. This feature is explicitly enabled in all 'A' and 'C' variants per Figure 2 and the Ordering Information table, preventing residual voltage from causing unintended logic states during shutdown.

What ceramic capacitor value is required for stable operation of the NCP145AMX120TCG?

The NCP145AMX120TCG is stable with a minimum effective output capacitance of 2.2 µF ceramic. The datasheet specifies this as "effective capacitance" - meaning the actual capacitance at DC bias and operating temperature - and confirms stability up to 10 µF. Using smaller values risks instability, while larger values improve transient response without compromising phase margin.

Can the NCP145AMX120TCG operate with an input voltage lower than its 1.20 V output?

No - the NCP145AMX120TCG cannot regulate with VIN < VOUT. Its absolute minimum VIN is specified as VOUT + VDO (1.20 V + 0.14 V = 1.34 V typ.), and the Absolute Maximum Ratings table defines VIN ≥ −0.3 V but requires VIN > VOUT for regulation. Attempting VIN = 1.0 V will result in dropout and unregulated output, as confirmed in Figure 6 and the Dropout Voltage test conditions.

What is the thermal resistance (R_JA) of the NCP145AMX120TCG in its XDFN4 package?

The NCP145AMX120TCG in the XDFN4 1.2 mm × 1.2 mm package has a junction-to-air thermal resistance (R_JA) of 170°C/W, measured on a 40 mm × 40 mm × 1.6 mm FR4 PCB with 2-ounce copper on top and bottom layers. This value assumes no additional heatsinking and defines the maximum power dissipation before reaching 150°C junction temperature under ambient conditions.