Texas Instruments LP38843T-0.8/NOPB

Overview

LP38843T-0.8/NOPB from Texas Instruments is a 3A ultra-low-dropout linear regulator with fixed 0.8V output, CMOS N-MOS pass transistor architecture, 210mV typical dropout at 3A, ±1.5% initial output accuracy, and stable operation with ceramic output capacitors ≥22µF. It powers microcontroller cores and FPGA I/O rails in space-constrained industrial embedded systems requiring precise low-voltage regulation.

For engineers reviewing the LP38843T-0.8/NOPB datasheet, LP38843T-0.8/NOPB pinout, LP38843T-0.8/NOPB application, or LP38843T-0.8/NOPB equivalent, key selection criteria include its dual-rail input (VIN + VBIAS), shutdown-controlled 30nA quiescent current, thermal shutdown protection, and TO-220 package suitability for convection-cooled 3A loads.

Technical Context

The LP38843T-0.8/NOPB uses an external bias rail (4.5–5.5V) to drive the gate of its N-MOS pass transistor, enabling ultra-low VIN operation down to VOUT + VDO. Its CMOS control circuitry draws only 30mA quiescent current from VIN and 2mA from VBIAS at full load, with ground pin current remaining low across all output currents.

Stability is achieved via internal compensation optimized for ceramic output capacitors (≥22µF) or tantalum (≥4.7µF), eliminating need for ESR-based zero placement. The device integrates over-temperature and over-current protection, with thermal shutdown activating when junction temperature exceeds +150°C.

Key Specifications

Pinout & Package

LP38843T-0.8/NOPB is housed in a 5-lead TO-220 (KC) package with exposed tab electrically connected to GND. The tab serves as primary thermal path and must be soldered to ≥1 in² copper area for optimal θJ-A performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A8300RGRT and MCP1826T-0802E/DB, LP38843T-0.8/NOPB uniquely supports sub-1V inputs via dedicated VBIAS, delivers superior PSRR for noisy SMPS environments, and integrates thermal protection-making it optimal for high-reliability, low-input-voltage core regulation.

Availability

LP38843T-0.8/NOPB is available at Aetrix Electronics and suitable for ASIC core supplies, SMPS post-regulators, and industrial PLC I/O modules requiring stable component supply with guaranteed long-term manufacturability.

Supply support for LP38843T-0.8/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 leader specializing in analog, embedded processing, and connectivity technologies, with decades of expertise in power management IC design and manufacturing.

The LP38843 series was engineered specifically for high-current, ultra-low-dropout regulation in digital system power rails-including microprocessor, FPGA, and ASIC core supplies-where precision, speed, and thermal robustness are critical.

FAQ

What is the minimum input voltage required for LP38843T-0.8/NOPB to regulate 0.8V output at 3A?

The LP38843T-0.8/NOPB requires a minimum input voltage of VOUT + VDO = 0.8V + 0.21V = 1.01V at 3A (typical). However, the VBIAS rail must simultaneously be maintained at 4.5–5.5V to ensure proper gate drive. This dual-rail architecture allows regulation even when VIN is only marginally above VOUT-unlike single-supply LDOs.

Can LP38843T-0.8/NOPB operate without an external VBIAS supply?

No. LP38843T-0.8/NOPB requires an external 4.5–5.5V VBIAS supply to drive the N-MOS pass transistor gate. If VBIAS falls below ~4V, under-voltage lockout disables regulation. The part cannot self-bias from VIN; omitting VBIAS will result in no output voltage regardless of VIN level.

What output capacitor is required for stable operation of LP38843T-0.8/NOPB?

LP38843T-0.8/NOPB requires ≥22µF of X7R or X5R ceramic capacitance on the output pin, placed within 1cm of the device and returned to clean analog ground. Tantalum capacitors are acceptable at ≥4.7µF but offer slower transient response and higher ESR-ceramic is preferred for noise-sensitive applications.

How does the shutdown function work on LP38843T-0.8/NOPB?

The SHUTDOWN pin (Pin 5) is active-low. Driving it below 0.3V turns off the output and reduces quiescent current to 30nA (typ). When unused, it must be tied to VBIAS-not left floating-to ensure reliable enablement. A 10–100kΩ pull-up resistor is recommended if driven by open-drain logic.

Is LP38843T-0.8/NOPB RoHS compliant and lead-free?

Yes. LP38843T-0.8/NOPB carries the "/NOPB" suffix indicating lead-free (Pb-free) packaging with Sn (tin) lead finish. It meets RoHS Directive 2011/65/EU requirements and is rated Level-1 (unlimited floor life) per JEDEC J-STD-020.