Texas Instruments LP38842SX-1.2/NOPB

Overview

LP38842SX-1.2/NOPB from Texas Instruments is a 1.5A ultra-low-dropout linear regulator with fixed 1.2V output, N-MOS pass transistor architecture, 115mV typical dropout at full load, ±1.5% initial output accuracy, and dual-supply operation (VIN + VBIAS). It delivers stable core voltage for FPGA I/O banks and DSP subsystems in space-constrained industrial embedded systems.

For engineers reviewing the LP38842SX-1.2/NOPB datasheet, LP38842SX-1.2/NOPB pinout, LP38842SX-1.2/NOPB application, or LP38842SX-1.2/NOPB equivalent, key selection criteria include ultra-low dropout under high current, ceramic capacitor compatibility (≥22µF), bias rail dependency (4.5–5.5V), thermal performance in DDPAK/TO-263, and shutdown functionality via S/D pin.

Technical Context

The LP38842SX-1.2/NOPB employs a CMOS-based N-MOS pass transistor driven by an independent VBIAS rail, enabling operation with VIN as low as VOUT + 115mV while maintaining regulation. Its control loop is optimized for stability with ≥22µF ceramic output capacitance, not tantalum.

It integrates over-temperature and over-current protection, achieves 30nA shutdown current when S/D is pulled low, and provides 80dB PSRR at 120Hz on VIN and 58dB on VBIAS-critical for noise-sensitive analog/digital mixed-signal domains.

Key Specifications

Pinout & Package

LP38842SX-1.2/NOPB is housed in a 5-pin DDPAK/TO-263 (KTT) package with exposed thermal pad soldered to PCB copper plane for heatsinking (θ_J-A ≈ 35°C/W with ≥1 in² copper).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPL7407LDR and TPS7A8300RGRT, LP38842SX-1.2/NOPB uniquely balances 1.5A current, 115mV dropout, and dual-rail flexibility-making it optimal for FPGA I/O banks and SMPS post-regulation where input headroom and bias isolation are critical.

Availability

LP38842SX-1.2/NOPB is available at Aetrix Electronics and suitable for server power delivery, industrial FPGA platforms, and medical imaging subsystems requiring stable component supply with long lifecycle support.

Supply support for LP38842SX-1.2/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 LP38842SX-1.2/NOPB belongs to TI's ultra-low-dropout linear regulator product line, engineered specifically for high-current, low-noise, thermally robust applications in computing, communications, and industrial infrastructure.

FAQ

What is the minimum input voltage required for LP38842SX-1.2/NOPB to maintain regulation?

The LP38842SX-1.2/NOPB requires VIN ≥ VOUT + VDO, where VDO is 115mV typical at 1.5A. Thus, minimum functional VIN is 1.315V under full load. However, VBIAS must also be present at 4.5–5.5V for gate drive-this bias rail is mandatory and independent of VIN.

Can LP38842SX-1.2/NOPB operate without the BIAS pin connected?

No. LP38842SX-1.2/NOPB cannot function without a valid 4.5–5.5V supply on the BIAS pin. The internal N-MOS gate driver relies entirely on this rail; absence or undervoltage (<~4V) triggers UVLO and disables output regulation regardless of VIN level.

What output capacitor types and values are validated for LP38842SX-1.2/NOPB stability?

LP38842SX-1.2/NOPB is stable with ≥22µF X7R or X5R ceramic capacitors. Tantalum is permitted at ≥4.7µF but not recommended due to reliability and ESR variability. Z5U/Y5V ceramics are prohibited-they lose >80% capacitance with temperature/voltage and risk instability.

How does the shutdown (S/D) pin behave electrically on LP38842SX-1.2/NOPB?

The S/D pin is active-low with threshold of 0.3–0.7V for turn-off and 0.7–1.3V for turn-on. When pulled ≤0.3V, LP38842SX-1.2/NOPB enters shutdown drawing 30nA; when ≥0.7V, it enables. If unused, tie directly to VBIAS-no external pull-up is needed in that case.

What thermal derating applies to LP38842SX-1.2/NOPB in its DDPAK/TO-263 package?

In DDPAK/TO-263 (KTT), LP38842SX-1.2/NOPB has θ_J-A ≈ 35°C/W with ≥1 in² copper. Maximum power dissipation must keep junction temperature ≤125°C. For example, at 25°C ambient and 1.5A load with 200mV dropout, PD ≈ 300mW-well within safe limits without heatsink.