Texas Instruments LP3856ESX-1.8/NOPB

Overview

LP3856ESX-1.8/NOPB from Texas Instruments is a 3A ultra-low-dropout linear regulator with fixed 1.8V output, TO-263-5 package, 390mV dropout at 3A, ±1.5% output voltage accuracy, and remote sense capability for improved load regulation in distributed power systems.

For engineers reviewing the LP3856ESX-1.8/NOPB datasheet, LP3856ESX-1.8/NOPB pinout, LP3856ESX-1.8/NOPB application, or LP3856ESX-1.8/NOPB equivalent, key selection considerations include dropout performance under 3A load, ceramic capacitor stability support, shutdown quiescent current (10nA), error flag functionality, and SENSE pin implementation for remote load regulation.

Technical Context

The LP3856ESX-1.8/NOPB uses a PMOS pass element on a CMOS process enabling ultra-low dropout and load-independent quiescent current. Its internal error amplifier compares either VOUT (LP3853) or SENSE (LP3856) to a precision bandgap reference, delivering fast transient response to step-load changes up to 3A.

It integrates overtemperature and overcurrent protection, features an open-drain ERROR flag with 10% hysteresis relative to VOUT, and requires external 10kΩ pull-up on SD and ERROR pins. The SENSE pin enables Kelvin sensing to compensate for IR drop in PCB traces between regulator and load.

Key Specifications

Pinout & Package

LP3856ESX-1.8/NOPB is housed in a TO-263-5 (D²Pak) thermally enhanced surface-mount package with exposed thermal pad. Pin 1 is SD (Shutdown), Pin 2 is VIN, Pin 3 is GND, Pin 4 is VOUT, and Pin 5 is SENSE - enabling remote-sense feedback for precise regulation at point-of-load.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS75718KTTT and TPS7A8300RGRT, LP3856ESX-1.8/NOPB uniquely combines 3A output, integrated SENSE, 10nA shutdown IQ, and TO-263-5 packaging-making it optimal for high-current, remote-sense, battery-sensitive applications where fixed 1.8V simplifies design.

Availability

LP3856ESX-1.8/NOPB is available at Aetrix Electronics and suitable for microprocessor core supplies, GTL bus terminators, DSP power management, battery-powered instrumentation, and other applications requiring stable component supply with guaranteed long-term availability.

Supply support for LP3856ESX-1.8/NOPB 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

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, designing and manufacturing analog ICs, embedded processors, and high-performance power management solutions.

The LP3856ESX-1.8/NOPB belongs to TI's LP385x ultra-low-dropout linear regulator family, engineered specifically for fast-response, low-noise, high-current power delivery in microprocessor, DSP, and bus-termination applications demanding precision regulation and robust thermal protection.

FAQ

What is the dropout voltage specification for LP3856ESX-1.8/NOPB at full 3A load?

The LP3856ESX-1.8/NOPB has a maximum dropout voltage of 600mV and a typical value of 390mV at 3A load and 25°C. This ultra-low dropout enables operation from as low as 2.19V input while maintaining regulated 1.8V output, making LP3856ESX-1.8/NOPB ideal for battery-backed or post-regulated systems with tight voltage margins.

Does LP3856ESX-1.8/NOPB support ceramic output capacitors, and what are the stability requirements?

Yes, LP3856ESX-1.8/NOPB is stable with ceramic output capacitors ranging from 10µF to 500µF depending on input capacitance and load current. For 3A operation, ≥10µF ceramic CIN is required; the maximum stable COUT scales with CIN - e.g., 10µF CIN supports up to ~50µF COUT at 3A. LP3856ESX-1.8/NOPB avoids ESR dependency, unlike many older LDOs.

How does the SENSE pin on LP3856ESX-1.8/NOPB improve regulation accuracy?

The SENSE pin on LP3856ESX-1.8/NOPB enables Kelvin sensing by connecting directly to the load, allowing the internal error amplifier to regulate voltage at the point-of-load rather than at the VOUT pin. This eliminates voltage drop across PCB traces, improving load regulation to ≤0.08% - a critical advantage in high-current, distributed power architectures where trace resistance causes significant error.

What is the function and interface requirement of the ERROR pin on LP3856ESX-1.8/NOPB?

The ERROR pin on LP3856ESX-1.8/NOPB is an open-drain output that pulls low when VOUT drops >10% below nominal (i.e., <1.62V for LP3856ESX-1.8/NOPB). It requires a 10kΩ–1MΩ pull-up resistor to VIN or logic supply. When unused, ERROR must be tied to GND. During shutdown, the ERROR signal is invalid - a design consideration for fault-monitoring systems using LP3856ESX-1.8/NOPB.

What thermal and protection features are integrated into LP3856ESX-1.8/NOPB?

LP3856ESX-1.8/NOPB integrates foldback current limiting, short-circuit protection, and thermal shutdown with auto-recovery. Under overload, it cycles the PMOS pass device to limit average power; sustained overtemperature triggers thermal shutdown. These protections operate independently of external components, ensuring robust operation in LP3856ESX-1.8/NOPB-based power systems without added discrete circuitry.