Texas Instruments LP38855T-0.8/NOPB

Overview

LP38855T-0.8/NOPB from Texas Instruments is a 1.5A fast-response, high-accuracy LDO linear regulator with enable, delivering a fixed 0.8V output voltage, 130 mV typical dropout at 1.5A, ±1.0% output tolerance at 25°C, and stable operation with 10 µF ceramic output capacitance. It powers DSP and FPGA core supplies in graphics cards and servers.

For engineers reviewing the LP38855T-0.8/NOPB datasheet, LP38855T-0.8/NOPB pinout, LP38855T-0.8/NOPB application, or LP38855T-0.8/NOPB equivalent, this page delivers verified package mapping (TO-220-5), confirmed thermal shutdown (160°C), EN pin threshold (1.25V typ), VBIAS operating range (3.0–5.5V), and real-world transient response data for SMPS post-regulation design.

Technical Context

The LP38855T-0.8/NOPB uses an N-MOS pass transistor architecture powered by dual rails: VIN supplies load current while VBIAS (3.0–5.5V) powers internal bias circuitry and gate drive. This enables ultra-low VIN operation down to VOUT + VDO.

It integrates under-voltage lockout (UVLO at 2.45V with 150 mV hysteresis), thermal shutdown (160°C), over-current protection, and fast transient response optimized for 10 µF ceramic output capacitors. The EN pin features 100 mV hysteresis and internal 180 kΩ pull-up to VBIAS.

Key Specifications

Pinout & Package

LP38855T-0.8/NOPB uses the TO-220-5 package (Package Number NDH0005D), with the metal tab electrically connected to GND and serving as primary thermal path to heatsink or PCB copper plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPL7407LPGQ1 and TPS7A8300RGRT, the LP38855T-0.8/NOPB uniquely combines fixed 0.8V output, dual-rail operation, TO-220 thermal performance, and guaranteed 130 mV dropout-making it optimal for space-constrained, high-current digital core rails where simplicity and thermal robustness are essential.

Availability

LP38855T-0.8/NOPB is available at Aetrix Electronics and suitable for ASIC core power supplies, DSP/FPGA core rails, and SMPS post-regulation requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for LP38855T-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 power management ICs, with decades of expertise in high-reliability power solutions.

The LP38855T-0.8/NOPB belongs to TI's high-current LDO family designed specifically for powering low-voltage digital cores in servers, graphics cards, and communications infrastructure where accuracy, transient response, and thermal resilience are critical.

FAQ

What is the minimum input voltage required for LP38855T-0.8/NOPB to regulate at full 1.5A load?

The LP38855T-0.8/NOPB requires VIN ≥ VOUT + VDO = 0.8V + 0.13V = 0.93V (typical) at 1.5A. However, per operating ratings, VIN must also be ≥ (VOUT + VDO) and ≤ VBIAS, and VBIAS must be between 3.0V and 5.5V. So practical minimum VIN is 0.93V, but system design must ensure VBIAS remains within its valid range independently.

Can LP38855T-0.8/NOPB operate without an external VBIAS supply?

No. LP38855T-0.8/NOPB requires a dedicated VBIAS supply between 3.0V and 5.5V to power internal circuitry and drive the N-MOS gate. It cannot self-bias from VIN. If only one supply is available, a separate LDO or DC/DC converter must generate VBIAS from VIN or another rail.

What output capacitor types are validated for stability with LP38855T-0.8/NOPB?

LP38855T-0.8/NOPB is stable with ≥10 µF ceramic capacitors (X5R or X7R dielectrics). Tantalum capacitors also provide stable operation, though their ESR may cause larger output voltage deviations during fast load transients. Aluminum electrolytics are not recommended below 0°C due to ESR rise.

Does LP38855T-0.8/NOPB include reverse current protection?

Yes-by architecture. The N-MOS pass transistor has no intrinsic body diode. Reverse current flow from OUT to IN is blocked unless VBIAS > UVLO threshold (2.45V) AND EN is asserted. During UVLO or EN = low, the gate is un-driven and reverse conduction is prevented.

What is the thermal resistance (θJA) of LP38855T-0.8/NOPB in its TO-220 package?

The LP38855T-0.8/NOPB in TO-220-5 package (NDH0005D) has a θJA of 60°C/W under standard JEDEC test conditions (no heatsink, no airflow). With proper heatsinking or mounting to a large copper plane, effective θJA can be reduced significantly-TI recommends using Equation (7) in the datasheet to calculate real-world thermal performance.