Texas Instruments LP3992IMFX-1.5/NOPB

Overview

LP3992IMFX-1.5/NOPB from Texas Instruments is a micropower CMOS low-dropout (LDO) voltage regulator delivering a precise 1.5 V ±0.09 V output from 1.9 V to 5.2 V input, with 30 mA guaranteed load current, 29 µA typical quiescent current, and <1.5 µA shutdown current. It serves as the primary power rail for ultra-low-power RF and digital baseband circuits in battery-operated wireless devices.

For engineers reviewing the LP3992IMFX-1.5/NOPB datasheet, LP3992IMFX-1.5/NOPB pinout, LP3992IMFX-1.5/NOPB application, or LP3992IMFX-1.5/NOPB equivalent, key selection criteria include its 1.9 V minimum input capability, 300 µVRMS output noise, fast 40 µs turnoff with internal discharge FET, stability with 1 µF ceramic capacitors, and thermal/short-circuit protection across –40°C to +125°C.

Technical Context

The LP3992IMFX-1.5/NOPB employs a CMOS pass transistor architecture with bandgap reference and error amplifier feedback, enabling operation down to 1.9 V input while maintaining regulation. Its enable-controlled shutdown activates an internal discharge path between OUT and GND via the CAP pin, achieving fast 40 µs turnoff and <1.5 µA quiescent draw.

Stability is ensured with 1 µF ceramic output capacitance connected to the dedicated CAP pin (not OUT), leveraging low-ESR ceramic characteristics (5–500 mΩ). The device integrates thermal overload and short-circuit current limiting (90 mA typical), and meets ±2000 V HBM ESD rating per JS-001.

Key Specifications

Pinout & Package

LP3992IMFX-1.5/NOPB is housed in a 5-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm, optimized for space-constrained portable PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLC7605IDBVR and MCP1700T-1502E/TT, LP3992IMFX-1.5/NOPB uniquely balances ultra-low IQ (29 µA), fast active shutdown (<1.5 µA), dedicated CAP pin for noise optimization, and 1.9 V minimum input - making it the only option among the three qualified for battery-powered RF subsystems demanding simultaneous low power, low noise, and precise enable timing.

Availability

LP3992IMFX-1.5/NOPB is available at Aetrix Electronics and suitable for GSM cellular handsets, Bluetooth audio peripherals, wideband CDMA baseband power management, and portable information appliance RTC/SRAM backup requiring stable component supply across automotive-grade temperature ranges.

Supply support for LP3992IMFX-1.5/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 connectivity technologies, with decades of leadership in power management innovation.

The LP3992IMFX-1.5/NOPB belongs to TI's micropower LDO family designed specifically for battery-powered portable electronics, emphasizing ultra-low quiescent current, low-input-voltage operation, and integrated protection for reliability in compact form factors.

FAQ

What is the minimum input voltage required for LP3992IMFX-1.5/NOPB to regulate at 1.5 V?

The LP3992IMFX-1.5/NOPB regulates continuously down to 1.9 V input voltage - enabling operation from nearly depleted single-cell batteries. This is confirmed in Section 6.3 (Recommended Operating Conditions) and Section 1 (Features) of the SNVS192C datasheet, where "Operation From a Low Input Voltage: 1.9 V" is explicitly stated. Below 1.9 V, dropout occurs and output voltage drops linearly with input.

How does the CAP pin on LP3992IMFX-1.5/NOPB differ from the OUT pin, and why is it required?

The CAP pin on LP3992IMFX-1.5/NOPB is the internally preferred connection point for the 1 µF output capacitor, while the OUT pin delivers regulated voltage to the load. Per Section 5 (Pin Configuration) and Section 9.2.2.3, connecting the capacitor to CAP - not OUT - ensures stability by minimizing loop gain phase shift. Using OUT instead risks oscillation due to added trace inductance; CAP provides a low-impedance, direct die bond-wire path to the error amplifier compensation node.

What is the typical quiescent current of LP3992IMFX-1.5/NOPB under full load, and how does it compare to shutdown mode?

The LP3992IMFX-1.5/NOPB draws 29 µA typical quiescent current at 30 mA load (Section 6.5, IQ specification), rising slightly to 50 µA maximum over temperature. In shutdown mode (EN ≤0.4 V), quiescent current drops to <1.5 µA - verified in Section 1 (Features) and Section 6.5 (ISC/Shutdown specs). This >19× reduction enables multi-week standby in portable devices.

Does LP3992IMFX-1.5/NOPB require external components beyond input and output capacitors?

No - LP3992IMFX-1.5/NOPB is a fully integrated LDO requiring only two external components: a 1 µF ceramic input capacitor between IN and GND, and a 1 µF ceramic output capacitor between CAP and GND. Section 9.2.2.1 confirms no resistors, diodes, or additional compensation networks are needed. The internal bandgap reference, error amplifier, and pass transistor eliminate all external feedback components.

What protection features are built into LP3992IMFX-1.5/NOPB, and how are they triggered?

LP3992IMFX-1.5/NOPB integrates thermal-overload protection (shuts down at 160°C junction temperature with 20°C hysteresis) and short-circuit current limiting (90 mA typical, per Section 6.5). Thermal protection activates when die temperature exceeds threshold, disabling output until cooldown. Short-circuit protection engages when output current exceeds limit, clamping IOUT without damaging the pass transistor - both features are fully internal and require no external circuitry.