Texas Instruments LP3990TLX-1.35/NOPB

Overview

LP3990TLX-1.35/NOPB from Texas Instruments is a 150-mA, 1.35-V fixed-output linear voltage regulator in a 6-pin WSON package, designed for low-noise digital power rails in portable systems. It delivers ±1.5% output voltage accuracy over –40°C to 125°C, operates from 2 V to 6 V input, achieves 120 mV dropout at full load, and consumes only 43 µA quiescent current when enabled-used in cellular handset core logic and PMIC subsystems.

For engineers reviewing the LP3990TLX-1.35/NOPB datasheet, LP3990TLX-1.35/NOPB pinout, LP3990TLX-1.35/NOPB application, or LP3990TLX-1.35/NOPB equivalent, key selection criteria include ceramic-capacitor stability (1 µF min), logic-controlled enable with internal 1-MΩ pull-down, thermal shutdown at 155°C, <10 nA shutdown IQ, and PSRR of 55 dB at 1 kHz.

Technical Context

The LP3990TLX-1.35/NOPB implements a PMOS pass transistor architecture enabling ultra-low dropout and fast 105 µs start-up time. Its internal reference and error amplifier maintain regulation across line (2–6 V) and load (0–150 mA) variations while rejecting input ripple via 55 dB PSRR at 1 kHz.

It integrates logic-level enable control with VIH = 0.95 V and VIL = 0.4 V thresholds, thermal overload protection that disables output above 155°C (with ~15°C hysteresis), and short-circuit current limiting at 550–1000 mA-ensuring robust operation in battery-powered digital loads without external protection circuitry.

Key Specifications

Pinout & Package

LP3990TLX-1.35/NOPB uses a 6-pin WSON (NGG) package measuring 2.90 mm × 1.60 mm with exposed thermal pad (connected to Pin 2/GND). The package supports high-density PCB layouts and efficient heat dissipation via bottom-side thermal conduction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LP3990TLX-1.35/NOPB, TPL7407LPGQ adds driver functionality at cost of regulation-only simplicity, while MCP1700T-1302E/TT trades thermal protection and tighter accuracy for lower static power-making LP3990TLX-1.35/NOPB optimal for safety-critical, noise-sensitive, or thermally constrained digital loads.

Availability

LP3990TLX-1.35/NOPB is available at Aetrix Electronics and suitable for cellular handsets, wearable sensor hubs, industrial PLC I/O modules, and medical patch monitors requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for LP3990TLX-1.35/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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions across industrial, automotive, and personal electronics markets.

The LP3990TLX-1.35/NOPB belongs to TI's precision low-dropout regulator product line, engineered specifically for space-constrained, battery-powered digital systems demanding low noise, fast transient response, and ceramic-capacitor compatibility.

FAQ

What is the minimum input voltage required for LP3990TLX-1.35/NOPB to regulate at full load?

The LP3990TLX-1.35/NOPB requires VIN ≥ (VOUT + VDO) = 1.35 V + 0.12 V = 1.47 V, but its recommended minimum operating input is 2 V per datasheet Section 6.3. Below 2 V, internal circuitry may not function reliably-even if dropout margin exists-so 2 V is the practical lower limit for guaranteed regulation across temperature and process variation.

Can LP3990TLX-1.35/NOPB operate without an output capacitor?

No, LP3990TLX-1.35/NOPB requires a minimum 1-µF ceramic output capacitor (X7R/X5R, ESR 5–500 mΩ) for stability, as confirmed in Section 6.6 and Figure 13 of the datasheet. Omitting COUT causes oscillation and loss of regulation; the device is not designed for no-capacitor operation.

Is the EN pin of LP3990TLX-1.35/NOPB compatible with 1.2-V GPIOs?

Yes, LP3990TLX-1.35/NOPB has VIH = 0.95 V (min) and VIL = 0.4 V (max), making it fully compatible with 1.2-V logic families. A 1.2-V high signal exceeds VIH by 0.25 V margin, ensuring robust enable activation across voltage and temperature extremes.

Does LP3990TLX-1.35/NOPB require a specific capacitor dielectric type for CIN and COUT?

TI recommends X7R or X5R ceramic capacitors for both CIN and COUT due to their stable capacitance vs. temperature and DC bias. Z5U/Y5V types are permitted but exhibit >50% capacitance loss at elevated temperatures or bias-X7R is preferred for industrial or medical applications where performance consistency is critical.

How does thermal shutdown behave in LP3990TLX-1.35/NOPB during sustained overload?

LP3990TLX-1.35/NOPB disables output at ~155°C junction temperature and re-enables at ~140°C (15°C hysteresis). Under continuous overload, this causes thermal cycling-repeated ON/OFF toggling-which limits average power dissipation but degrades reliability if sustained. Proper PCB copper pour and thermal vias are essential to avoid entering this mode.