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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Power Management - Specialized

Texas Instruments LP3971SQX-8858/NOPB

Name: LP3971SQX-8858/NOPB
Brand: Texas Instruments
SKU: LP3971SQX-8858/NOPB
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LP3971SQX-8858/NOPB

Manufacturer:: Texas Instruments

Category:: Power Management - Specialized

Package:: 40-WFQFN Exposed Pad

Datasheet:: LP3971SQX-8858/NOPB.pdf

Description:: IC PMU FOR APP PROCESSOR 40WQFN

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Product details

Overview

LP3971SQX-8858/NOPB from Texas Instruments is a programmable power management unit (PMU) designed for advanced application processors, integrating three synchronous buck regulators (1.2V, 1.2V, 3.3V), six LDOs (including 30 mA RTC LDO), I²C interface, and backup battery charger. It delivers up to 1.6 A per buck channel with ±3% output voltage accuracy and operates across −40°C to +85°C ambient temperature.

For engineers reviewing the LP3971SQX-8858/NOPB datasheet, LP3971SQX-8858/NOPB pinout, LP3971SQX-8858/NOPB application, or LP3971SQX-8858/NOPB equivalent, key selection criteria include its 40-pin WQFN package, dynamic voltage management (DVM) support, I²C-programmable VOUT configuration, and integrated backup battery switching logic for RTC power continuity.

Technical Context

The LP3971SQX-8858/NOPB implements a multi-rail PMU architecture with three independent buck converters (SW1–SW3) using internal PFET/NFET switches (RDSON_P = 240 mΩ, RDSON_N = 200 mΩ), each supporting forced PWM or PFM mode and synchronization via external clock on SYNC pin. Its six LDOs feature low dropout (100 mV typ for RTC LDO at 10 mA), ±3% accuracy, and programmable enable sequencing via SYS_EN and PWR_EN control inputs.

Internal logic includes thermal shutdown at 160°C, current overload protection, and hardware-based battery switchover: RTC LDO automatically transitions from main battery to backup coin cell when VIN falls below 2.8V (with 3.1V hysteresis), signaled by nBATT_FLT. All regulator outputs are software-configurable over I²C (400 kHz high-speed mode).

Key Specifications

Parameter	Value and Actual Design Meaning
Buck Output Voltage (BUCK1)	1.2 V - configured via PWR_EN enable and factory-default coding; supports dynamic voltage scaling in processor core domains.
Buck Output Voltage (BUCK2)	1.2 V - independently set via PWR_EN; enables dual-core or I/O rail regulation with tight coupling to system power states.
Buck Output Voltage (BUCK3)	3.3 V - configured via SYS_EN; supplies peripheral interfaces requiring stable 3.3 V with up to 1.6 A capability.
LDO_RTC Output	2.8 V - fixed non-tracking output; powers real-time clock circuitry with automatic switchover to backup battery below 2.8 V.
LDO4 / LDO5 Outputs	1.2 V / 1.8 V - factory-programmed via SYS_EN; supply low-voltage I/O banks or memory interfaces with 150/370 mA max current.
Efficiency (BUCK1 @ 500 mA)	95% - achieved using synchronous rectification and optimized gate drive; reduces thermal load in compact handheld enclosures.
I²C Interface Speed	400 kHz - high-speed mode compatible; enables rapid reconfiguration of all regulator settings without CPU intervention delay.
Package	40-pin WQFN (5 mm × 5 mm, RSB0040A) - exposes thermal pad (BGND1,2,3) for PCB-level heat dissipation in thermally constrained designs.

Pinout & Package

LP3971SQX-8858/NOPB uses a 40-pin, 5 mm × 5 mm, 0.4 mm pitch WQFN package (TI package code RSB0040A) with exposed thermal pad connected to BGND1,2,3 pins. Pin 1 is marked by circle on top view; bottom-side thermal slug requires solder connection to PCB ground plane for optimal thermal performance.

Pin/Terminal	Circuit Role	Design Meaning
PWR_ON	Active-HI push-button input	Initiates system power-on/off sequence; triggers EXT_WAKEUP pulse and register 0x02 status update for CPU wake-up handling.
EXT_WAKEUP	Open-drain output	Generates 10 ms active-low pulse to CPU upon PWR_ON/nTEST_JIG/SPARE event; eliminates need for external interrupt logic.
SCL / SDA	I²C clock/data bidirectional	Enable full software control of all regulator voltages, enable states, fault reporting, and battery charger configuration.
GPIO1/nCHG_EN	Configurable I/O	Functions as general-purpose output or external backup battery charger enable; grounding enables continuous charging from main source.
nBATT_FLT	Open-drain fault indicator	Asserts low when main battery voltage drops below 2.4–3.4 V (default 2.8 V); signals imminent RTC switchover to backup power.
SW1 / SW2 / SW3	Buck switch node outputs	Drive external 2.2 µH inductors; require ceramic output capacitors (≥8 µF) and proper layout to minimize EMI and ensure stability.

Key Features

Feature	Design Value
Triple synchronous buck regulators	Each delivers up to 1.6 A with internal 240 mΩ PFET / 200 mΩ NFET switches; eliminates need for external MOSFETs and reduces BOM count.
RTC LDO with auto battery switchover	2.8 V output with seamless transition between main battery and lithium-manganese coin cell at 2.8 V threshold (3.1 V hysteresis); ensures uninterrupted RTC operation.
I²C programmability of all rails	Full voltage, enable/disable, and sequencing control via 400 kHz interface; supports dynamic voltage management (DVM) for application processor power optimization.
Integrated backup battery charger	Programmable 150/300/370 mA charge current; terminates at 2.91–3.1 V; supports Li-MnO₂ coin cells and supercapacitors without external components.
Thermal and current protection	160°C junction shutdown with 20°C hysteresis; cycle-by-cycle current limiting on all bucks; prevents damage during overload or poor heatsinking.
Low-noise LDOs with high PSRR	45 dB PSRR at 10 kHz (LDO1–5); 100 mV typical dropout at 10 mA (RTC LDO); suitable for noise-sensitive analog/RF subsystems.

Applications

Smartphone Baseband Power	Digital Camera Sensor Supply
Use Scenario: Powers Marvell PXA or Samsung application processor cores, memory I/O, and peripherals in slim smartphone form factors with aggressive thermal limits. IC Role / Device Role / Timing Role: Central PMU managing dynamic voltage scaling (DVM) across CPU, GPU, and DDR I/O rails via I²C commands synchronized to processor power states. Use Value: Enables 1.2 V/1.2 V/3.3 V triple-buck configuration matching LP3971SQX-8858/NOPB's factory defaults, reducing design iteration time and eliminating discrete regulator tuning.	Use Scenario: Supplies image sensor analog front-end, ISP core, and flash LED driver in portable digital cameras requiring clean, sequenced power. IC Role / Device Role / Timing Role: Delivers low-noise 2.8 V to RTC and 1.2 V/1.8 V to sensor logic while coordinating startup timing via SYS_EN/PWR_EN enable hierarchy. Use Value: Integrates backup battery switchover and I²C-controlled LDO trimming, ensuring accurate timestamping and sensor bias stability during battery swaps or low-VIN conditions.
Personal Media Player SoC	PDA Phone Application Processor
Use Scenario: Manages power for ARM-based media SoCs with multiple voltage domains (core, memory, audio codec, display interface) in battery-constrained devices. IC Role / Device Role / Timing Role: Provides three buck regulators for core/memory rails and six LDOs for low-current analog blocks, all coordinated through single I²C bus. Use Value: Factory-configured 1.2 V/1.2 V/3.3 V buck outputs and 1.2 V/1.8 V LDOs match common SoC domain requirements, minimizing firmware initialization overhead.	Use Scenario: Powers Freescale i.MX or similar PDA phone processors with integrated cellular modem, requiring robust RTC retention and fast wake-up response. IC Role / Device Role / Timing Role: Acts as primary power controller with PWR_ON-triggered wake-up, EXT_WAKEUP pulse generation, and nBATT_FLT fault signaling to baseband processor. Use Value: Built-in 10 ms EXT_WAKEUP pulse and hardware-level battery fault detection eliminate external glue logic, reducing PCB area and system latency.

Smartphone Baseband Power

Digital Camera Sensor Supply

Use Scenario: Powers Marvell PXA or Samsung application processor cores, memory I/O, and peripherals in slim smartphone form factors with aggressive thermal limits.

IC Role / Device Role / Timing Role: Central PMU managing dynamic voltage scaling (DVM) across CPU, GPU, and DDR I/O rails via I²C commands synchronized to processor power states.

Use Value: Enables 1.2 V/1.2 V/3.3 V triple-buck configuration matching LP3971SQX-8858/NOPB's factory defaults, reducing design iteration time and eliminating discrete regulator tuning.

Use Scenario: Supplies image sensor analog front-end, ISP core, and flash LED driver in portable digital cameras requiring clean, sequenced power.

IC Role / Device Role / Timing Role: Delivers low-noise 2.8 V to RTC and 1.2 V/1.8 V to sensor logic while coordinating startup timing via SYS_EN/PWR_EN enable hierarchy.

Use Value: Integrates backup battery switchover and I²C-controlled LDO trimming, ensuring accurate timestamping and sensor bias stability during battery swaps or low-VIN conditions.

Personal Media Player SoC

PDA Phone Application Processor

Use Scenario: Manages power for ARM-based media SoCs with multiple voltage domains (core, memory, audio codec, display interface) in battery-constrained devices.

IC Role / Device Role / Timing Role: Provides three buck regulators for core/memory rails and six LDOs for low-current analog blocks, all coordinated through single I²C bus.

Use Value: Factory-configured 1.2 V/1.2 V/3.3 V buck outputs and 1.2 V/1.8 V LDOs match common SoC domain requirements, minimizing firmware initialization overhead.

Use Scenario: Powers Freescale i.MX or similar PDA phone processors with integrated cellular modem, requiring robust RTC retention and fast wake-up response.

IC Role / Device Role / Timing Role: Acts as primary power controller with PWR_ON-triggered wake-up, EXT_WAKEUP pulse generation, and nBATT_FLT fault signaling to baseband processor.

Use Value: Built-in 10 ms EXT_WAKEUP pulse and hardware-level battery fault detection eliminate external glue logic, reducing PCB area and system latency.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TPS65023RSBT	Three bucks (1.0–3.3 V), 5 LDOs, no integrated backup battery charger; uses 48-pin VQFN; lacks RTC battery switchover logic.	Requires external charger circuit for coin-cell backup; better suited for systems where RTC retention is handled separately.	Select when higher LDO count (5 vs. 6) and wider buck VOUT range are prioritized over integrated battery management.
LP3972SQX-8858/NOPB	Pin-compatible variant with identical pinout and default VOUTs; differs only in internal mask ROM programming for I²C address and boot-up register values.	No functional difference in power delivery or sequencing; validated drop-in replacement per TI documentation.	Choose for identical electrical behavior and mechanical fit-no layout or firmware changes required.

Compared with TPS65023RSBT, LP3971SQX-8858/NOPB provides integrated backup battery charging and automatic RTC switchover, reducing component count by two ICs; versus LP3972SQX-8858/NOPB, it offers identical functionality but distinct I²C address and default register map-firmware must be verified for compatibility.

Availability

LP3971SQX-8858/NOPB is available at Aetrix Electronics and suitable for smartphone baseband power, digital camera sensor supply, and personal media player SoC applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LP3971SQX-8858/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 engineered specifically for advanced application processors in handheld devices, delivering tightly integrated, I²C-programmable multi-rail power with DVM support and battery-aware system management.

FAQ

What is the default output voltage configuration of LP3971SQX-8858/NOPB?

The LP3971SQX-8858/NOPB is factory-programmed with BUCK1 = 1.2 V (PWR_EN enabled), BUCK2 = 1.2 V (PWR_EN), BUCK3 = 3.3 V (SYS_EN), LDO_RTC = 2.8 V (non-tracking), LDO4 = 1.2 V (SYS_EN), and LDO5 = 1.8 V (SYS_EN). These defaults align with common application processor domain requirements and can be modified via I²C.

Does LP3971SQX-8858/NOPB support dynamic voltage management (DVM)?

Yes, LP3971SQX-8858/NOPB supports DVM through its I²C interface, allowing real-time adjustment of all buck and LDO output voltages during operation. This enables voltage scaling for CPU/GPU cores based on workload, directly supporting energy-efficient operation in advanced application processors.

How does the backup battery switchover work on LP3971SQX-8858/NOPB?

LP3971SQX-8858/NOPB automatically switches the RTC LDO supply from main battery to backup coin cell when main battery voltage falls below 2.8 V (typical), with 3.1 V hysteresis to prevent oscillation. The nBATT_FLT pin asserts low to signal this condition, and the transition occurs without software intervention.

What package type and thermal characteristics does LP3971SQX-8858/NOPB use?

LP3971SQX-8858/NOPB uses a 40-pin WQFN package (5 mm × 5 mm, RSB0040A) with exposed thermal pad connected to BGND1,2,3. Its θJA is 25°C/W under JEDEC JESD51-7 test conditions, and maximum power dissipation at TA = 70°C is 2.2 W-requiring adequate PCB copper area for thermal relief.

Can LP3971SQX-8858/NOPB be used without I²C configuration?

Yes, LP3971SQX-8858/NOPB operates autonomously using factory-default voltage settings and enable logic (SYS_EN/PWR_EN). I²C is optional for runtime reconfiguration; all regulators power up in their programmed states without host communication, making it suitable for simple boot sequences.

LP3971SQX-8858/NOPB Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: -

Package/Case:: 40-WFQFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Applications:: Processor

Current - Supply:: 60µA

Voltage - Supply:: 2.7V ~ 5.5V

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 40-WQFN (5x5)

LP3971SQX-8858/NOPB FAQ

1.How can I place an order for LP3971SQX-8858/NOPB through Aetrix?

Please submit a Request for Quotation (RFQ) for LP3971SQX-8858/NOPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LP3971SQX-8858/NOPB reliable?

The price and inventory of LP3971SQX-8858/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP3971SQX-8858/NOPB is usually 5 days.

3.What payment methods are accepted for LP3971SQX-8858/NOPB?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP3971SQX-8858/NOPB transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LP3971SQX-8858/NOPB?

LP3971SQX-8858/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LP3971SQX-8858/NOPB order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LP3971SQX-8858/NOPB?

For technical support, including LP3971SQX-8858/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP3971SQX-8858/NOPB requirements.

6.How does Aetrix verify that LP3971SQX-8858/NOPB is sourced from the original manufacturer or authorized distributors?

All LP3971SQX-8858/NOPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LP3971SQX-8858/NOPB meets industry standards.

7.What is the process for return or replacement of LP3971SQX-8858/NOPB?

All LP3971SQX-8858/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP3971SQX-8858/NOPB, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LP3971SQX-8858/NOPB part is unused and in its original packaging.

Return procedure for LP3971SQX-8858/NOPB:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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