Texas Instruments LP38842T-1.2/NOPB

Overview

LP38842T-1.2/NOPB from Texas Instruments is a 1.5A ultra-low-dropout linear regulator in TO-220-5 package, delivering fixed 1.2V output with 115mV typical dropout at full load, ±1.5% initial accuracy, and stable operation with ceramic output capacitors ≥22µF. It employs dual-rail architecture (VIN + VBIAS) to enable sub-1V input-to-output differentials and serves as a post-regulator for FPGA/DSP core supplies.

For engineers reviewing the LP38842T-1.2/NOPB datasheet, LP38842T-1.2/NOPB pinout, LP38842T-1.2/NOPB application, or LP38842T-1.2/NOPB equivalent, key selection criteria include dropout voltage under 1.5A load, bias rail dependency (4.5–5.5V), shutdown quiescent current (<0.06µA), thermal resistance (θ_J-A = 65°C/W, no heatsink), and compatibility with low-ESR ceramic output capacitors.

Technical Context

The LP38842T-1.2/NOPB uses an N-MOS pass transistor driven by a separate VBIAS rail (4.5–5.5V), decoupling gate drive from power path and enabling ultra-low dropout. Its CMOS-based control circuitry achieves 30nA shutdown current and maintains stability with ≥22µF ceramic or ≥4.7µF tantalum output capacitance.

It features internal overtemperature and overcurrent protection, 15µs turn-on delay, and 20µs turn-off delay. PSRR reaches 80dB at 120Hz on VIN and 58dB on VBIAS, while output noise is 150µV_rms (10Hz–100kHz) at 1.2V output.

Key Specifications

Pinout & Package

LP38842T-1.2/NOPB is housed in a 5-pin TO-220 (KC) package with exposed tab electrically connected to GND. The tab must be soldered to PCB ground copper for thermal and electrical integrity.

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 LT3080IDDPBF, LP38842T-1.2/NOPB uniquely combines fixed 1.2V output, dual-rail bias operation for ultra-low VIN, and TO-220 thermal robustness-making it optimal for industrial post-regulation where layout simplicity, thermal headroom, and bias rail availability exist.

Availability

LP38842T-1.2/NOPB is available at Aetrix Electronics and suitable for ASIC power supplies, server core voltage regulation, and DSP/FPGA core supplies requiring stable component supply, long-term industrial lifecycle support, and RoHS-compliant TO-220 packaging.

Supply support for LP38842T-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 power management ICs, with decades of expertise in high-reliability linear regulators and power solutions.

The LP38842 series was designed specifically for high-current, low-noise post-regulation in digital systems-targeting FPGA, DSP, and ASIC core supplies where ultra-low dropout, ceramic capacitor compatibility, and thermal resilience are critical.

FAQ

What is the minimum input voltage required for LP38842T-1.2/NOPB to regulate 1.2V output at 1.5A?

The LP38842T-1.2/NOPB requires a minimum input-to-output differential of 115mV (typical) at 1.5A, meaning VIN must be ≥1.315V. However, the BIAS rail must simultaneously be maintained at 4.5–5.5V for proper gate drive. This dual-rail requirement means the absolute minimum VIN depends on system-level bias availability-not just dropout voltage alone.

Can LP38842T-1.2/NOPB operate without the BIAS pin connected?

No. The LP38842T-1.2/NOPB requires a valid 4.5–5.5V supply on the BIAS pin to drive the N-MOS pass transistor gate. Leaving BIAS unconnected or outside this range prevents regulation and may trigger under-voltage lockout. If only one supply is available, a dedicated LDO or resistor divider from VIN (if VIN ≥4.5V) must feed BIAS.

What output capacitor is required for stable operation of LP38842T-1.2/NOPB?

LP38842T-1.2/NOPB requires ≥22µF of X7R or X5R ceramic capacitance placed within 1cm of the OUTPUT pin and returned to clean analog ground. Tantalum capacitors are acceptable at ≥4.7µF but offer slower transient response. Z5U/Y5V ceramics are prohibited due to severe capacitance loss with voltage and temperature.

Does LP38842T-1.2/NOPB have built-in protection features?

Yes. LP38842T-1.2/NOPB integrates thermal shutdown and current limiting to protect against overload and overheating. It also features under-voltage lockout on the BIAS rail (activates below ~4V) and a dedicated active-low shutdown (S/D) pin that reduces quiescent current to 30nA when asserted.

Is LP38842T-1.2/NOPB pin-compatible with other variants in the LP38842 family?

Yes. All LP38842 variants-including LP38842T-0.8/NOPB, LP38842T-1.5/NOPB, and LP38842S-1.2/NOPB-share identical 5-pin TO-220 (LP38842T-xx) or DDPAK/TO-263 (LP38842S-xx) pinouts and electrical behavior. Only the fixed output voltage and package type differ; PCB layout is interchangeable across same-package variants.