Texas Instruments LP3991TLX-1.3/NOPB

Overview

LP3991TLX-1.3/NOPB from Texas Instruments is a fixed-output 1.3-V, 300-mA low-dropout (LDO) regulator in a 4-pin DSBGA package, designed for post-regulation of DC-DC converters and battery-powered digital loads. It operates from 1.65 V to 4 V input, delivers ±1% output accuracy at room temperature, maintains regulation down to 125-mV dropout at full load, and draws only 50 µA quiescent current at 1-mA load.

For engineers reviewing the LP3991TLX-1.3/NOPB datasheet, LP3991TLX-1.3/NOPB pinout, LP3991TLX-1.3/NOPB application, or LP3991TLX-1.3/NOPB equivalent, key selection considerations include its 1.3-V fixed output, DSBGA-4 footprint compatibility with space-constrained portable designs, ceramic capacitor stability (2.2 µF minimum for ≤1.3 V), and enable-controlled shutdown with 1.2-MΩ internal pulldown.

Technical Context

The LP3991TLX-1.3/NOPB integrates a PMOS pass transistor enabling ultra-low dropout (125 mV @ 300 mA) and high PSRR (65 dB @ 1 kHz), making it suitable for noise-sensitive digital core rails downstream of switching regulators. Its internal enable logic features precise VIH = 0.95 V and VIL = 0.4 V thresholds, with an integrated 1.2-MΩ pulldown resistor ensuring default-off behavior.

Stability is guaranteed with small-footprint ceramic capacitors - as low as 2.2 µF (X7R/X5R, ESR 5–500 mΩ) for 1.3-V output - and operation is specified across –40°C to +125°C junction temperature. Thermal shutdown activates at 160°C with 20°C hysteresis, and short-circuit current is limited to 550–900 mA.

Key Specifications

Pinout & Package

LP3991TLX-1.3/NOPB uses a 4-pin DSBGA (YZR) package with 1.43 mm × 0.96 mm nominal body size and bottom-side solder bumps. The package is optimized for minimal PCB area and thermal conduction via the four terminals directly to the board.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LP3991TLX-1.3/NOPB, TPS7A0513PDQNR offers lower quiescent current but sacrifices 100 mA output capacity and 125-mV dropout performance, while TPL7407LPGEDR embeds the 1.3-V rail within a multi-function driver IC - neither matches the LP3991TLX-1.3/NOPB's combination of 300-mA capability, ultra-low dropout, and standalone precision regulation in DSBGA-4.

Availability

LP3991TLX-1.3/NOPB is available at Aetrix Electronics and suitable for mobile processor core rails, wearable sensor hubs, industrial IoT edge nodes, and automotive infotainment subsystems requiring stable component supply with tight voltage tolerance and low-noise performance.

Supply support for LP3991TLX-1.3/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 decades of expertise in power management IC design and manufacturing.

The LP3991TLX-1.3/NOPB belongs to TI's precision LDO family targeting space-constrained, battery-powered digital systems - engineered for post-DC-DC regulation, low-noise core supplies, and fast-enable portable applications.

FAQ

What is the minimum input voltage required for LP3991TLX-1.3/NOPB to regulate at 1.3 V?

The LP3991TLX-1.3/NOPB requires a minimum input voltage of 1.43 V to maintain regulation at 1.3 V output, based on its 125-mV dropout specification at 300 mA. At lighter loads, dropout decreases - e.g., 55–90 mV at 150 mA - allowing operation from as low as ~1.36 V input under partial load. Input must remain ≥1.65 V per absolute minimum rating.

Can LP3991TLX-1.3/NOPB operate with a 2.2-µF output capacitor?

Yes - LP3991TLX-1.3/NOPB is explicitly qualified for stable operation with a 2.2-µF ceramic capacitor (X7R or X5R dielectric, ESR 5–500 mΩ) when VOUT ≤1.3 V, as stated in the datasheet footnote. This reduces PCB area versus the 4.7-µF option, though load transient response degrades by ~10–15% peak deviation.

Does LP3991TLX-1.3/NOPB require an external pull-up on the EN pin?

No - LP3991TLX-1.3/NOPB includes an internal 1.2-MΩ pulldown resistor on the EN pin, ensuring default-off behavior when left floating. A pull-up is only needed to actively enable the device; a 0.95-V threshold means it can be driven directly from 1.2-V or 1.8-V GPIO without level shifting.

What is the thermal resistance (RθJA) of LP3991TLX-1.3/NOPB in its DSBGA package?

The LP3991TLX-1.3/NOPB in the YZR (DSBGA-4) package has a junction-to-ambient thermal resistance (RθJA) of 189.7°C/W on a high-K test board per JEDEC JESD51-7. Real-world RθJA depends on PCB copper area and thermal vias; adding a 100-mm² thermal pad with 4× thermal vias typically reduces RθJA to ~60–80°C/W.

Is LP3991TLX-1.3/NOPB suitable for automotive applications?

LP3991TLX-1.3/NOPB is qualified for operation across –40°C to +125°C junction temperature and includes thermal shutdown and short-circuit protection - meeting baseline reliability requirements for under-hood and cabin automotive subsystems. However, it is not AEC-Q100 qualified; for certified automotive use, consult TI's AEC-Q100 LDO portfolio.