NXP Semiconductors LD6816CX4/30P,315

Overview

LD6816CX4/30P,315 from NXP Semiconductors is a 3.0 V fixed-output, 150 mA ultra-low-dropout linear regulator in WLCSP4 package (0.76 mm × 0.76 mm), featuring 45 mV dropout at full load, 30 µV_RMS output noise (10 Hz–100 kHz), and integrated auto-discharge pull-down transistor for rapid output discharge during disable. It powers low-voltage analog/digital interfaces in space-constrained mobile devices.

For engineers reviewing the LD6816CX4/30P,315 datasheet, LD6816CX4/30P,315 pinout, LD6816CX4/30P,315 application, or LD6816CX4/30P,315 equivalent, key selection criteria include its 3.0 V output accuracy (±2% over −30°C to +85°C), 55 dB PSRR at 1 kHz, <150 µs startup time, and WLCSP4 thermal performance (R_th(j-a) = 130 K/W) in high-density portable PCB layouts.

Technical Context

The LD6816CX4/30P,315 implements a PMOS pass transistor architecture enabling ultra-low dropout operation down to 45 mV at 150 mA, with internal voltage reference and error amplifier delivering tight output regulation across input range (2.3 V–5.5 V). Its enable logic uses active-HIGH EN pin with VIH ≥ 1.1 V and VIL ≤ 0.4 V.

Unlike high-ohmic disable variants (e.g., /xxH), this /30P version integrates a dedicated pull-down transistor (R_pd = 100 Ω typical) that actively discharges the output node during shutdown-critical for systems requiring fast power-state transitions and preventing floating rail conditions in multi-rail mobile SoC domains.

Key Specifications

Pinout & Package

Package: Wafer-Level Chip-Scale Package (WLCSP4), 0.4 mm pitch, 0.76 mm × 0.76 mm × 0.47 mm footprint, Pb-free/RoHS-compliant, halogen- and antimony-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6219B302MR-G and RT9013-30GB, the LD6816CX4/30P,315 delivers superior dropout performance and integrated auto-discharge in the smallest footprint-making it optimal for next-generation ultra-thin mobile devices where board area and power sequencing integrity are critical.

Availability

LD6816CX4/30P,315 is available at Aetrix Electronics and suitable for smartphone application processors, digital camera sensors, portable media player audio codecs, and personal navigation device GPS front-ends requiring stable component supply with guaranteed long-term availability.

Supply support for LD6816CX4/30P,315 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

NXP Semiconductors is a global semiconductor company specializing in secure connectivity solutions for automotive, industrial, and consumer markets, with leadership in power management and RF technologies.

The LD6816 series was designed specifically for ultra-miniaturized portable electronics requiring ultra-low-noise, ultra-low-dropout regulation with intelligent power sequencing-targeting smartphones, wearables, and IoT edge sensors.

FAQ

What is the nominal output voltage and tolerance of the LD6816CX4/30P,315?

The LD6816CX4/30P,315 provides a fixed 3.0 V output with ±2% tolerance over the operating temperature range of −30°C to +85°C and load current from 1 mA to 150 mA. This accuracy is specified in Table 9 of the NXP datasheet and ensures reliable operation of 3.0 V I/O interfaces without external trimming. The LD6816CX4/30P,315 maintains this tolerance even under varying line and load conditions due to its high PSRR and low load regulation error (0.0025%/mA).

Does the LD6816CX4/30P,315 include an auto-discharge function, and how does it operate?

Yes, the LD6816CX4/30P,315 integrates an on-chip pull-down transistor that provides low-ohmic output discharge during disable mode-confirmed by its "P" suffix and R_pd = 100 Ω typical value. When EN is driven LOW, the output is actively pulled to GND, discharging a 1 µF capacitor to 10% of 3.0 V in ~300 µs. This eliminates floating outputs and enables deterministic power sequencing in multi-rail mobile SoCs. The LD6816CX4/30P,315 differs from /xxH variants which enter high-ohmic state instead.

What are the recommended output capacitor requirements for stable operation of the LD6816CX4/30P,315?

The LD6816CX4/30P,315 requires a minimum 0.7 µF (±30%) X7R ceramic capacitor at the OUT pin, with 1.0 µF recommended for optimal transient response and stability. The capacitor must have ESR between 5 mΩ and 500 mΩ per Table 10. Using a 1.0 µF X7R part with ~20 mΩ ESR ensures proper phase margin and meets the <150 µs startup specification. Deviating below 0.7 µF risks oscillation or excessive overshoot during enable transitions. The LD6816CX4/30P,315's stability is validated only with these external capacitor parameters.

How does the LD6816CX4/30P,315 achieve its ultra-low dropout voltage, and what is the practical impact?

The LD6816CX4/30P,315 achieves 45 mV typical dropout at 150 mA using a PMOS pass transistor architecture, which operates in linear region with minimal V_DS. This allows the input voltage to drop as low as 3.045 V while maintaining regulated 3.0 V output-extending usable battery voltage range by ~150 mV compared to standard LDOs. In practice, this translates directly to longer talk time in single-cell Li-ion powered devices. The LD6816CX4/30P,315's dropout remains stable across temperature (−40°C to +85°C) and load, as verified in Figure 7 of the datasheet.

What thermal performance can be expected from the LD6816CX4/30P,315 in a typical two-layer PCB layout?

In a standard two-layer PCB per the datasheet test condition, the LD6816CX4/30P,315 exhibits a typical junction-to-ambient thermal resistance (R_th(j-a)) of 130 K/W. With 150 mA output current and 45 mV dropout, power dissipation is ~6.75 mW-resulting in only ~0.88°C junction-to-ambient rise above ambient. To maintain this performance, all four WLCSP4 solder bumps must connect to large copper areas; adding thermal vias beneath the package further reduces R_th(j-a). The LD6816CX4/30P,315's monolithic silicon process and WLCSP4 construction inherently minimize thermal impedance versus leaded packages.