Texas Instruments LP38856T-1.2/NOPB

Overview

LP38856T-1.2/NOPB from Texas Instruments is a 3-A, fast-response, high-accuracy LDO linear regulator with dual-rail operation (VIN and VBIAS), delivering 1.2 V output with ±1% tolerance at 25°C, 240 mV typical dropout at full load, and stable operation with only 10-µF ceramic output capacitance - used in FPGA core power, DSP supply rails, and SMPS post-regulation.

For engineers reviewing the LP38856T-1.2/NOPB datasheet, LP38856T-1.2/NOPB pinout, LP38856T-1.2/NOPB application, or LP38856T-1.2/NOPB equivalent, key selection considerations include its dual-input architecture (VIN + VBIAS), ultra-low ground current (10 mA typ. at 3 A), thermal shutdown (160°C), UVLO hysteresis (150 mV), and compatibility with low-ESR ceramic capacitors without external compensation.

Technical Context

The LP38856T-1.2/NOPB uses an N-MOS pass transistor driven by a separate VBIAS rail (3–5.5 V), enabling ultra-low VIN operation down to VOUT + VDO while isolating bias circuitry from high-current paths. Its CMOS control architecture delivers fast transient response (<20 µs turn-on) and low quiescent current across load range.

It integrates undervoltage lockout (UVLO threshold 2.45 V, 150 mV hysteresis), overtemperature shutdown (160°C, 10°C hysteresis), and current limiting (6.2 A short-circuit protection). The enable pin features internal 180-kΩ pull-up to VBIAS and 100-mV hysteresis for noise immunity.

Key Specifications

Pinout & Package

LP38856T-1.2/NOPB is housed in a 5-pin TO-220 package (14.986 mm × 10.16 mm) with exposed tab thermally connected to GND. The tab serves as primary heat path and must be soldered to a copper pour or heatsink for thermal compliance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A8300RGRT and LT3072EFE#PBF, the LP38856T-1.2/NOPB uniquely balances ultra-low dropout, dual-rail flexibility, and TO-220 thermal robustness - making it optimal for industrial and server applications where VIN margin is constrained and heatsinking is practical.

Availability

LP38856T-1.2/NOPB is available at Aetrix Electronics and suitable for FPGA core power, DSP processor supply, and SMPS post-regulation requiring stable component supply, long-term lifecycle support, and traceable sourcing for production ramp.

Supply support for LP38856T-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 company designing analog ICs, embedded processors, and power management solutions for industrial, automotive, and communications markets.

The LP38856T-1.2/NOPB belongs to TI's high-current LDO family engineered for demanding digital core and interface power applications - emphasizing fast transient response, dual-input flexibility, and thermal resilience in high-power density systems.

FAQ

What is the minimum input voltage required for LP38856T-1.2/NOPB to regulate 1.2 V output?

The LP38856T-1.2/NOPB requires VIN ≥ VOUT + VDO. With a typical dropout voltage of 240 mV at 3 A, the minimum functional VIN is 1.44 V. However, per datasheet recommended conditions, VIN must be ≥ VOUT + 0.3 V (i.e., ≥1.5 V) to ensure full specification compliance across temperature and load. Below that, regulation may degrade or UVLO may engage if VBIAS is marginal.

Can LP38856T-1.2/NOPB operate with VIN and VBIAS supplied from the same 5-V rail?

Yes - the LP38856T-1.2/NOPB supports shared-rail operation. When VIN = VBIAS = 5 V, the device functions normally, drawing bias current from the same source as the main input. This simplifies power tree design in systems with a single clean 5-V supply, though PSRR performance is optimized when VBIAS is filtered separately.

What capacitor types and values are mandatory for stable operation of LP38856T-1.2/NOPB?

Stable operation of LP38856T-1.2/NOPB requires: COUT ≥10 µF X5R/X7R ceramic placed ≤1 cm from OUT and GND pins; CIN ≥10 µF X5R/X7R ceramic at IN; and CBIAS ≥1 µF ceramic at BIAS. Z5U/Y5V dielectrics are not recommended due to capacitance loss over temperature. Tantalum may be added in parallel but is not a substitute for the minimum ceramic.

Does LP38856T-1.2/NOPB require an external resistor network to set output voltage?

No - LP38856T-1.2/NOPB is a fixed-output variant. The "-1.2" suffix denotes factory-trimmed 1.2 V output; no external feedback resistors are needed or supported. This eliminates layout sensitivity and improves accuracy versus adjustable LDOs, which rely on resistor tolerance and PCB leakage.

How does the enable (EN) pin behave when left unconnected on LP38856T-1.2/NOPB?

When left floating, the EN pin is pulled up internally to VBIAS via ~180 kΩ, turning the LP38856T-1.2/NOPB ON. However, stray capacitance can delay startup; TI recommends tying EN directly to VBIAS if enable control is unused. Driving EN <1 V disables the part, sinking only 1 µA typical - ideal for low-power sequencing.