NXP Semiconductors LD6816CX4/29P,315

Overview

LD6816CX4/29P,315 from NXP Semiconductors is a 2.9 V fixed-output, 150 mA ultra-low-dropout linear regulator in WLCSP4 package (0.76 mm × 0.76 mm × 0.47 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 low-ohmic output during disable-optimized for power-sensitive mobile interfaces in smartphones and portable media players.

For engineers reviewing the LD6816CX4/29P,315 datasheet, LD6816CX4/29P,315 pinout, LD6816CX4/29P,315 application, or LD6816CX4/29P,315 equivalent, key selection criteria include its 2.9 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 space-constrained PCB layouts.

Technical Context

The LD6816CX4/29P,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 ensuring stable regulation across input voltages from 2.3 V to 5.5 V. Its enable input (active HIGH, V_IH ≥ 1.1 V) controls both regulation and the integrated pull-down switch.

Thermal shutdown (160°C trigger, 20 K hysteresis) and current limiting (600 mA short-circuit protection) are embedded, while ESD robustness reaches ±10 kV HBM. The device operates across −40°C to +85°C ambient, with junction temperature limited to +125°C under recommended PCB layout conditions.

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 XC6219B292MR-G and RT9013-29GB, the LD6816CX4/29P,315 delivers superior dropout (45 mV), smaller footprint (0.76 mm²), and built-in auto-discharge-making it optimal for space- and efficiency-critical mobile applications where precise 2.9 V regulation and clean power sequencing are mandatory.

Availability

LD6816CX4/29P,315 is available at Aetrix Electronics and suitable for smartphone power management, portable camera sensor biasing, GPS RF front-end supplies, and audio codec analog rails requiring stable component supply with guaranteed long-term availability.

Supply support for LD6816CX4/29P,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 leader focused on secure connectivity solutions for automotive, industrial, and consumer markets, with deep expertise in power management and RF technologies.

The LD6816 series was designed specifically for ultra-miniaturized, low-noise, high-efficiency power delivery in portable electronics-addressing stringent requirements for dropout, noise, and footprint in next-generation mobile devices.

FAQ

What is the nominal output voltage and tolerance of the LD6816CX4/29P,315?

The LD6816CX4/29P,315 provides a fixed 2.9 V output with ±2% accuracy over the operating temperature range of −30°C to +85°C. This specification is verified per Table 9 in the NXP datasheet and applies under 1 mA load conditions at +25°C ambient. The LD6816CX4/29P,315 maintains this tolerance across its full 150 mA load range and input voltage span (2.3 V to 5.5 V), making it suitable for precision voltage rail applications.

Does the LD6816CX4/29P,315 include an auto-discharge function, and how does it operate?

Yes, the LD6816CX4/29P,315 integrates an auto-discharge function via an internal 100 Ω pull-down transistor connected to the OUT pin. When the EN pin is driven LOW (≤0.4 V), the regulator disables and the pull-down actively sinks current to GND, rapidly discharging external output capacitance. This eliminates floating outputs and supports reliable power sequencing-confirmed in Section 1.2 and Table 9 of the LD6816_SER datasheet.

What is the minimum recommended output capacitor for stable operation of the LD6816CX4/29P,315?

The LD6816CX4/29P,315 requires a minimum 0.7 µF ceramic output capacitor (X7R dielectric preferred) with ESR between 5 mΩ and 500 mΩ. The datasheet recommends 1.0 µF for optimal transient response and stability across temperature. This capacitor must be placed as close as possible to the IN and OUT pins, with solid ground connections to minimize loop inductance and ensure reliable regulation under dynamic load steps.

How does the LD6816CX4/29P,315 perform in terms of power supply rejection ratio (PSRR)?

The LD6816CX4/29P,315 achieves 55 dB PSRR at 1 kHz under 1 mA load, as specified in Table 9 of the NXP datasheet. PSRR degrades with increasing load current and frequency-e.g., ~45 dB at 100 kHz-but remains effective for suppressing mid-frequency switching noise from upstream DC-DC converters. This performance is enabled by its internal error amplifier bandwidth and PMOS pass transistor characteristics.

What package type and dimensions does the LD6816CX4/29P,315 use?

The LD6816CX4/29P,315 uses a Wafer-Level Chip-Scale Package (WLCSP4) with 2×2 solder bumps on a 0.4 mm pitch. Its physical dimensions are 0.76 mm × 0.76 mm × 0.47 mm (typical), per Table 14 and Figure 24 in the datasheet. The package is Pb-free, RoHS-compliant, and halogen-free, and requires reflow soldering-not wave soldering-due to its solder-ball construction.