onsemi NCP161AMX285TBG

Overview

NCP161AMX285TBG from onsemi is a 450 mA ultra-low-noise, high-PSRR LDO regulator with fixed 2.85 V output, designed for RF and analog circuits. It delivers ±2% output accuracy over load/temperature, 150 mV dropout at 450 mA, 98 dB PSRR at 1 kHz, and 10 µV_RMS output noise - enabling clean power in sensitive wireless receivers and camera sensor rails.

For engineers reviewing the NCP161AMX285TBG datasheet, pinout, applications, or equivalent options, key selection criteria include its 2.85 V fixed output, XDFN4 1 mm × 1 mm package, active discharge capability, compatibility with 1 µF ceramic input/output capacitors, and thermal shutdown protection at 160°C.

Technical Context

The NCP161AMX285TBG uses a PMOS pass transistor architecture to achieve low dropout and reverse-current immunity. Its bandgap reference and integrated soft-start ensure stable startup under varying load conditions, while the enable logic (EN threshold: 1.2 V high / 0.4 V low) supports precise power sequencing in multi-rail systems.

It features active output discharge (280 Ω pull-down when disabled), thermal shutdown with hysteresis (160°C trip / 140°C release), and current limiting (700 mA typ.) - all operating across −40°C to +125°C junction temperature. Stability is guaranteed with 1 µF X7R/X5R ceramic capacitors and ESR < 2 Ω on the output.

Key Specifications

Pinout & Package

XDFN4 package: 1 mm × 1 mm × 0.4 mm, exposed thermal pad (EPAD) tied to GND for enhanced thermal dissipation. Pin pitch: 0.65 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A20285PDBVR and BD3572FP-E2, the NCP161AMX285TBG uniquely balances 450 mA capability, industry-leading 98 dB PSRR, and 10 µV_RMS noise in a 1 mm × 1 mm XDFN4 footprint - making it optimal for miniaturized RF/analog systems where both size and spectral purity are constrained.

Availability

NCP161AMX285TBG is available at Aetrix Electronics and suitable for 5G front-end modules, smartphone camera ISPs, and Wi-Fi 6 baseband processors requiring stable component supply, consistent parametric performance, and long-term production continuity.

Supply support for NCP161AMX285TBG 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 is a global semiconductor supplier delivering energy-efficient silicon solutions for automotive, industrial, cloud, medical, and IoT applications - with leadership in power management, imaging, and signal processing.

The NCP161AMX285TBG belongs to onsemi's ultra-low-noise LDO family, engineered specifically for RF transceiver and high-fidelity analog circuitry where power integrity directly impacts signal fidelity and system-level RF performance.

FAQ

What is the maximum input voltage rating for the NCP161AMX285TBG?

The NCP161AMX285TBG has an absolute maximum input voltage rating of 6 V. Operation above 5.5 V is not recommended per specifications, and sustained exposure beyond 6 V may cause permanent damage. For reliable 2.85 V output, the recommended input range is 1.9 V to 5.5 V - ensuring adequate headroom for dropout and line regulation.

Does the NCP161AMX285TBG support active output discharge, and how does it function?

Yes, the NCP161AMX285TBG supports active output discharge. When the EN pin voltage falls below 0.4 V, the internal 280 Ω discharge resistor connects OUT to GND, rapidly discharging the output capacitor. This feature prevents floating voltages and unintended wake-up in power-gated subsystems - critical for smartphone and IoT device power sequencing.

Can the NCP161AMX285TBG operate stably with a 0.7 µF output capacitor?

Yes, the NCP161AMX285TBG is designed to remain stable with a minimum effective output capacitance of 0.7 µF - accounting for capacitance loss due to DC bias, temperature, and package size (e.g., 0201 MLCCs). However, 1 µF is recommended for optimal transient response and PSRR performance across full operating conditions.

What is the thermal shutdown behavior of the NCP161AMX285TBG?

The NCP161AMX285TBG triggers thermal shutdown at approximately 160°C junction temperature and automatically recovers when the die cools to ~140°C. During shutdown, the pass transistor turns off and output is disabled. This hysteresis prevents oscillation near the trip point and protects against catastrophic failure during sustained overload or inadequate PCB copper area.

How does the NCP161AMX285TBG compare to the NCP161AFCS285T2G variant?

The NCP161AMX285TBG uses the XDFN4 package (1 mm × 1 mm), while the NCP161AFCS285T2G uses WLCSP4 (0.64 mm × 0.64 mm). Both share identical electrical specs - 2.85 V output, 450 mA, active discharge, and noise/PSRR performance - but differ in thermal resistance (XDFN4 R_JA = 198.1°C/W vs. WLCSP4 R_JA = 108°C/W) and mounting requirements.