NXP Semiconductors LD6938CX6/18125PLJ

Overview

LD6938CX6/18125PLJ from NXP Semiconductors is a dual low-dropout (LDO) voltage regulator IC delivering two independent 300 mA outputs with fixed nominal voltages of 1.8 V (OUT1) and 1.25 V (OUT2), 240 mV dropout at full load, 70 µV RMS output noise (10 Hz–100 kHz), and 80 dB PSRR at 1 kHz - designed for power management in space-constrained portable electronics.

For engineers reviewing the LD6938CX6/18125PLJ datasheet, LD6938CX6/18125PLJ pinout, LD6938CX6/18125PLJ application, or LD6938CX6/18125PLJ equivalent, key selection considerations include dual-output sequencing capability, auto-discharge mode on disable, ultra-low 1.0 µA standby current, WLCSP6 package compatibility with high-density PCB layouts, and thermal shutdown protection at 160 °C.

Technical Context

The LD6938CX6/18125PLJ integrates two independent LDO regulators sharing a common input but featuring separate enable inputs (EN1, EN2) and output pins (OUT1, OUT2), each with dedicated soft-start and foldback current limiting. Its -PL suffix denotes auto-discharge functionality on disable, implemented via an internal 100 Ω pull-down resistor per output.

This device operates across 1.7 V to 5.5 V input range, supports 1.2 V–3.3 V fixed output combinations, and maintains regulation over −40 °C to +85 °C ambient temperature with junction temperature up to +125 °C. Thermal protection triggers shutdown at 160 °C with 20 K hysteresis.

Key Specifications

Pinout & Package

LD6938CX6/18125PLJ uses a 6-bump Wafer-Level Chip-Scale Package (WLCSP6) measuring 1.2 mm × 0.8 mm × 0.47 mm with 0.4 mm pitch and bottom-side solder bumps. The package requires Pb-free reflow profile peaking at 230–260 °C and is optimized for high thermal conductivity via direct die attachment to PCB copper layers.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6216D1812MR-G and RP512K1812-TR, the LD6938CX6/18125PLJ uniquely combines dual 300 mA capability, 100 Ω auto-discharge, 70 µV noise, and sub-1 mm² WLCSP6 packaging - making it optimal for next-generation portable devices where size, noise, and sequencing control are critical.

Availability

LD6938CX6/18125PLJ is available at Aetrix Electronics and suitable for smartphones, tablet PCs, and digital still cameras requiring stable component supply, consistent parametric performance, and long-term lifecycle support.

Supply support for LD6938CX6/18125PLJ 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 headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and consumer markets.

The LD6938 series belongs to NXP's power management portfolio targeting ultra-compact, low-noise dual-LDO regulation for battery-powered portable electronics - emphasizing minimal footprint, high PSRR, and intelligent power sequencing.

FAQ

What output voltages does the LD6938CX6/18125PLJ provide?

The LD6938CX6/18125PLJ delivers fixed nominal output voltages of 1.8 V on OUT1 and 1.25 V on OUT2, as indicated by the "/18125PL" suffix in the part number. These values are factory-trimmed and do not require external feedback resistors. Both outputs maintain regulation across input voltages from 1.7 V to 5.5 V and load currents up to 300 mA each.

Does the LD6938CX6/18125PLJ support independent enable control for each regulator?

Yes, the LD6938CX6/18125PLJ features two separate enable inputs: EN1 controls OUT1 and EN2 controls OUT2. Each is active-high with VIH ≥ 1.1 V and VIL ≤ 0.4 V. This allows flexible power sequencing - for example, enabling OUT1 first to power I/O before bringing up the 1.25 V core rail on OUT2 - and independent shutdown for dynamic power management.

What is the purpose of the auto-discharge function in the LD6938CX6/18125PLJ?

The auto-discharge function in the LD6938CX6/18125PLJ actively pulls OUT1 and OUT2 to GND through internal 100 Ω resistors when their respective enable pins (EN1 or EN2) are driven LOW. This rapidly discharges downstream capacitive loads, preventing floating outputs and ensuring predictable power-down behavior - essential for reliable reset sequencing and avoiding latch-up in interconnected logic.

What is the maximum allowable input voltage for the LD6938CX6/18125PLJ?

The absolute maximum input voltage (VI) for the LD6938CX6/18125PLJ is +6.0 V for transient conditions up to 4 ms, per the limiting values table. For continuous operation, the recommended input voltage range is 1.7 V to 5.5 V. Exceeding 5.5 V continuously risks exceeding thermal limits or triggering overvoltage-related failure mechanisms, even if within absolute max ratings.

How does the LD6938CX6/18125PLJ handle thermal overload?

The LD6938CX6/18125PLJ incorporates thermal shutdown protection that activates at a junction temperature of 160 °C, halting output regulation until the die cools by at least 20 K (hysteresis). During shutdown, both outputs enter high-impedance state unless auto-discharge is active - in which case OUT1 and OUT2 remain pulled to GND via their internal 100 Ω resistors. This protects the IC and surrounding components from sustained overheating.