Texas Instruments LP3971SQX-W416/NOPB

Overview

LP3971SQX-W416/NOPB from Texas Instruments is a programmable power management unit (PMU) for advanced application processors, integrating three 1.6A buck regulators, six LDOs (including 30mA RTC LDO), I²C-controlled backup battery charger, and dual GPIOs in a 40-pin 5×5 mm WQFN package. It delivers ±3% output voltage accuracy, up to 95% buck efficiency, and supports dynamic voltage management for Marvell PXA, Freescale, and Samsung processors.

For engineers reviewing the LP3971SQX-W416/NOPB datasheet, LP3971SQX-W416/NOPB pinout, LP3971SQX-W416/NOPB application, or LP3971SQX-W416/NOPB equivalent, this PMU enables precise multi-rail sequencing, battery-fault-aware RTC power switching, and software-configurable VOUT across all regulators - critical for PDA phones, smart phones, and digital camera power architectures.

Technical Context

The LP3971SQX-W416/NOPB implements three synchronous buck converters with internal 240 mΩ PFET and 200 mΩ NFET switches, operating at 2 MHz nominal frequency or synchronizable to external 10.4–15.6 MHz clocks via SYNC pin. Each buck supports programmable VOUT from 0.725 V to 3.3 V with 50–600 mV resolution and delivers up to 1.6 A with thermal shutdown at 160°C.

Its six LDOs include a dedicated 30 mA RTC LDO with automatic main-to-backup battery switchover (2.8 V threshold, 3.1 V hysteresis), four general-purpose LDOs (150–370 mA), and one 300 mA LDO, all featuring ±3% accuracy, <100 mV dropout (typ), and 45 dB PSRR at 10 kHz. Control is fully I²C-based with register-mapped enable, voltage, and fault status.

Key Specifications

Pinout & Package

The LP3971SQX-W416/NOPB uses a 40-pin WQFN package (Package Number RSB0040A) with exposed thermal pad (BGND1,2,3 pins 34 and bottom-side slug). Pin 1 is marked by circle on top view; pin numbering follows standard counter-clockwise sequence.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power management unit applications.

Compared with TPS65023RSBR and MAX8649ETE+, the LP3971SQX-W416/NOPB uniquely integrates RTC battery switchover, programmable backup charging, and full I²C control of all six LDOs - making it the only option for designs requiring autonomous, software-managed backup power without added components.

Availability

LP3971SQX-W416/NOPB is available at Aetrix Electronics and suitable for smartphone baseband power, digital camera sensor rail, PDA phone system management, and portable media player audio applications requiring stable component supply and long-term industrial availability.

Supply support for LP3971SQX-W416/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 power management technologies, with decades of experience in mobile and portable power solutions.

The LP3971 product line was designed specifically for advanced application processors requiring dynamic voltage management, multi-rail sequencing, and autonomous backup power - targeting PDA phones, smart phones, and personal media players circa 2006–2013.

FAQ

What is the default output voltage configuration for LP3971SQX-W416/NOPB?

The LP3971SQX-W416/NOPB is factory-configured with SYS_EN enabling LDO1 at 3.0 V, LDO2 at 3.3 V, LDO3 at 3.3 V, LDO4 at 1.0 V, LDO5 at 1.0 V, BUCK1 at 1.2 V, BUCK2 at 3.0 V, BUCK3 at 1.8 V, and LDO_RTC at 2.8 V. These defaults are set by internal mask ROM and can be overridden via I²C writes to voltage control registers after power-up.

Does LP3971SQX-W416/NOPB support external clock synchronization for its buck regulators?

Yes, LP3971SQX-W416/NOPB supports external clock synchronization via the SYNC pin (Pin 35). When driven with a 10.4–15.6 MHz signal - such as from an application processor's PLL - the internal buck oscillator locks to that frequency, reducing beat-frequency noise and enabling deterministic EMI filtering in dense RF environments.

How does the LP3971SQX-W416/NOPB handle main-to-backup battery switchover for the RTC LDO?

The LP3971SQX-W416/NOPB automatically switches the RTC LDO input from main battery to backup battery when VIN falls below 2.8 V (typical threshold), with 3.1 V hysteresis to prevent chatter. This behavior is hardware-controlled and requires no firmware intervention - ensuring RTC continuity even during sudden main battery removal or deep discharge.

Can LP3971SQX-W416/NOPB charge supercapacitors as well as lithium-manganese coin cells?

Yes, LP3971SQX-W416/NOPB supports both lithium-manganese coin cells and supercapacitors via its integrated backup battery charger. The charger delivers programmable currents (150/300/370 mA) and terminates at 3.1 V - appropriate for Li-MnO₂ cells and compatible with supercapacitor charging profiles when paired with external current-limiting resistors per TI Application Report SLVA318.

What thermal protection features are implemented in LP3971SQX-W416/NOPB?

LP3971SQX-W416/NOPB includes thermal shutdown at 160°C (typical) with 20°C hysteresis, plus current overload protection on all buck regulators and LDOs. When triggered, the device disables affected outputs and asserts nRSTO to signal system reset - preventing permanent damage during sustained overload or poor PCB thermal design.