Texas Instruments LP3991TLX-2.0/NOPB

Overview

LP3991TLX-2.0/NOPB from Texas Instruments is a fixed 2.0-V, 300-mA low-dropout linear regulator in a 4-pin DSBGA package, designed for post-regulation of DC-DC converters in space-constrained digital systems. It operates from 1.65 V to 4 V input, delivers ±1% output accuracy at room temperature, maintains 125-mV dropout at full load, and supports stable operation with 2.2 µF ceramic output capacitors - enabling use in battery-powered handheld devices and low-voltage SoC power rails.

For engineers reviewing the LP3991TLX-2.0/NOPB datasheet, LP3991TLX-2.0/NOPB pinout, LP3991TLX-2.0/NOPB application, or LP3991TLX-2.0/NOPB equivalent, key selection criteria include its 50-µA quiescent current at light load, 65 dB PSRR at 1 kHz, 100-µs startup time, thermal shutdown protection, and compatibility with 0402-size ceramic capacitors - all critical for portable, noise-sensitive, and thermally constrained designs.

Technical Context

The LP3991TLX-2.0/NOPB integrates a PMOS pass transistor with internal current limiting and thermal overload protection, enabling robust operation across –40°C to +125°C junction temperature. Its enable pin features a 1.2-MΩ internal pulldown resistor and logic-level thresholds (VIH = 0.95 V, VIL = 0.4 V), supporting direct interfacing with low-voltage GPIOs.

Designed specifically for low-noise post-buck regulation, it achieves 280 µVRMS output noise (10 Hz–100 kHz) and exhibits fast transient response (≤140 mV undershoot/overshoot for 0→300 mA load step), with inrush current limited to 600 mA - minimizing stress on upstream switching regulators and PCB layout complexity.

Key Specifications

Pinout & Package

LP3991TLX-2.0/NOPB uses a 4-pin DSBGA (YZR) package measuring 1.43 mm × 0.96 mm with 0.5-mm pitch, optimized for ultra-compact PCB layouts. The bottom-side bump configuration provides low thermal resistance (RθJB = 112.9°C/W) and requires solder-mask-defined pads per TI DSBGA mounting guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPL7407LPGEDR (non-LDO driver) and TPS7A0520PDBVR (lower-performance SOT-23 LDO), LP3991TLX-2.0/NOPB uniquely combines ultra-small DSBGA packaging, 300-mA capability, 65 dB PSRR, and 0402 capacitor compatibility - making it the only viable option for next-generation wearable and ultra-thin mobile power architectures.

Availability

LP3991TLX-2.0/NOPB is available at Aetrix Electronics and suitable for mobile baseband power, wearable sensor hubs, industrial IoT edge nodes, and automotive infotainment displays requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for LP3991TLX-2.0/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 delivering analog and embedded processing solutions, with over 90 years of innovation in power management ICs and precision analog components.

The LP3991TLX-2.0/NOPB belongs to TI's low-noise, low-voltage LDO family engineered for post-regulation in portable electronics - emphasizing minimal footprint, ultra-low quiescent current, and compatibility with advanced ceramic capacitors in space- and power-constrained applications.

FAQ

What is the minimum input voltage required for LP3991TLX-2.0/NOPB to regulate 2.0 V?

The LP3991TLX-2.0/NOPB requires a minimum input voltage of 2.125 V to maintain regulation at 2.0 V output under 300-mA load, based on its 125-mV dropout specification. At lighter loads, VIN can be reduced further - down to 1.65 V minimum per datasheet - but full-load regulation begins at VIN ≥ VOUT + VDO = 2.125 V. This enables efficient operation across most of the Li-ion battery discharge curve.

Can LP3991TLX-2.0/NOPB operate without an output capacitor?

No, LP3991TLX-2.0/NOPB requires an output capacitor for stability. For the 2.0-V version, a minimum 2.2 µF X7R or X5R ceramic capacitor is mandatory - with ESR between 5 mΩ and 500 mΩ - placed within 1 cm of the OUT pin and connected to a clean ground. Omitting or undersizing COUT risks oscillation, excessive noise, and failure to regulate.

Does LP3991TLX-2.0/NOPB support adjustable output voltage?

No, LP3991TLX-2.0/NOPB is a fixed-output device configured at the factory for 2.0 V. It does not include feedback pins or external resistor networks for adjustment. For programmable or different fixed voltages, TI offers other members of the LP3991 family (e.g., LP3991TLX-1.8/NOPB or LP3991TLX-2.5/NOPB), but each requires separate ordering and layout validation.

How does the EN pin function on LP3991TLX-2.0/NOPB?

The EN pin on LP3991TLX-2.0/NOPB is an active-high enable input with a 1.2-MΩ internal pulldown resistor. It turns the regulator on when driven ≥0.95 V and disables output when ≤0.4 V. In shutdown mode, quiescent current drops to ~2 nA. If enable functionality is unused, tie EN directly to VIN to ensure permanent operation - no external pullup is needed.

Is LP3991TLX-2.0/NOPB compatible with lead-free reflow processes?

Yes, LP3991TLX-2.0/NOPB is RoHS-compliant and qualified for standard lead-free reflow profiles per JEDEC J-STD-020. Its DSBGA (YZR) package uses SnAgCu solder bumps and withstands peak temperatures up to 260°C. Follow TI's DSBGA mounting guidelines - including solder paste volume control and reflow ramp rates - to ensure reliable interconnect formation and avoid light-sensitivity-related defects.