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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Battery Chargers

STMicroelectronics L6924U

Name: L6924U
Brand: STMicroelectronics
SKU: L6924U
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L6924U

Manufacturer:: STMicroelectronics

Category:: Battery Chargers

Package:: 16-VFQFN Exposed Pad

Datasheet:: L6924U.pdf

Description:: IC BATT CHG LI-ION 1CEL 16VFQFPN

Quantity:: RFQ Add To RFQ list

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Product details

Overview

L6924U from STMicroelectronics is a monolithic linear/quasi-pulse battery charger IC for single-cell Li-Ion/Li-Polymer batteries, integrating power MOSFET, reverse-blocking diode, current-sense resistor, and thermal protection in a 3×3 mm VFQFPN16 package. It supports dual-input (USB or AC adapter), delivers up to 1 A fast-charge current in AC mode, regulates output at 4.2 V ±1%, and implements closed-loop thermal control with NTC/PTC interface - used in compact portable devices like GPS units and digital cameras.

For engineers reviewing the L6924U datasheet, L6924U pinout, L6924U application, or L6924U equivalent, key selection criteria include input voltage range (2.5–12 V), programmable charge current (up to 1 A), thermal foldback behavior, status pin logic (open-collector ST1/ST2), and gas-gauge functionality via IEND pin voltage proportional to charging current.

Technical Context

The L6924U operates in two distinct charging modes: linear mode when powered by regulated sources (e.g., 5 V USB or 5–12 V AC adapter), delivering precise constant-current/constant-voltage (CC/CV) charging; and quasi-pulse mode when powered by current-limited adapters, where it leverages upstream current limiting to reduce on-die power dissipation. Its internal thermal control loop activates at ~120 °C junction temperature, dynamically reducing charge current to maintain safe operation.

It features dual-mode input selection (MODE pin), USB current scaling (ISEL pin), programmable termination current (IEND pin with resistor), and adaptive pre-charge (IPRE = 10% of fast-charge current when VBATT < 3.0 V). The integrated power MOSFET has RDS(on) = 280–380 mΩ, enabling efficient low-dropout operation down to VIN = 2.5 V.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	2.5 V to 12 V - supports wide-range USB (5 V) and wall adapters (5–12 V); startup threshold is 4.1 V.
Output Voltage Accuracy	4.2 V ±1% - ensures safe Li-Ion cell termination without overvoltage risk; referenced to internal 1.8 V ±2% VREF.
Max Fast-Charge Current	1 A (AC mode, IAC pin) / 500 mA (USB high-power mode, IUSB + ISEL HIGH) - set by external resistor with ±7% accuracy.
Thermal Protection	Closed-loop junction temperature regulation at ~120 °C - reduces charge current in real time to prevent thermal runaway.
NTC/PTC Interface	TH pin accepts resistor divider with thermistor - enables programmable hot/cold thresholds (10–15% and 40–60% of VREF) for battery temperature monitoring.
Status Outputs	ST1 and ST2 are open-collector pins - drive LEDs directly or interface with MCU GPIOs for charge state indication (e.g., charging/done/fault).
Gas Gauge Function	IEND pin voltage ∝ charging current - provides analog current feedback (e.g., 16 mA termination threshold yields ~51.2 mV across 3.3 kΩ) for host microcontroller ADC reading.

Pinout & Package

Package: VFQFPN16 (3 × 3 mm, 0.5 mm pitch, exposed thermal pad).

Pin/Terminal	Circuit Role	Design Meaning
1 (VIN)	Power stage input	Primary high-side input for power MOSFET; accepts 2.5–12 V; handles full charge current path.
2 (VINSNS)	Signal supply reference	Bias rail for analog circuitry; must be ≥ VIN − 0.3 V; decoupling critical for stability.
4 (ST1, ST2)	Status outputs	Open-collector outputs - pulled low during specific states (e.g., ST1 = charging active, ST2 = charge complete).
5 (TPRG)	Charge timer programming	Connects to capacitor-to-GND; sets maximum charge time (e.g., 10 nF → 3 hours); tolerance affects safety timeout.
6 (GND)	Power and signal ground	Common return for power stage, analog blocks, and thermal pad - must be low-impedance and thermally coupled.
7 (SD)	Shutdown control	Active-low enable; grounded = operational, floating = shutdown (I_SHDN ≈ 60–90 µA).
8 (TH)	Temperature sense input	Reads NTC/PTC voltage divider - triggers thermal fault if outside programmable window (e.g., cold < 40% VREF).
9 (ISEL)	USB current mode select	High = USB high-power (≤500 mA), Low = USB low-power (≤100 mA); ignored in AC mode.
10 (VOSNS)	Battery voltage sense	Direct feedback for CV regulation; enables battery presence detection via forced current sink.
11 (VOUT)	Charging output	Connected directly to battery anode; integrates reverse-blocking diode - prevents battery discharge into input.
12 (VREF)	Internal reference output	1.8 V ±2% precision reference - used by TH, IEND, and internal regulation loops.
13 (IEND)	Charge termination & gas gauge	Voltage across external resistor ∝ I_CHG; sets termination threshold (e.g., 3.3 kΩ → 16 mA) and enables real-time current monitoring.
14 (MODE)	Input source selector	Low = AC adapter mode (IAC controls current), High = USB mode (IUSB + ISEL control current).
15 (IUSB)	USB charge current set	Resistor-to-GND sets fast-charge current in USB mode (±7% accuracy); independent of IAC setting.
16 (IAC)	AC charge current set	Resistor-to-GND sets fast-charge current in AC mode (±7% accuracy); dominates when MODE = LOW.

Key Features

Feature	Design Value
Dual-input source management	Hardware-selectable AC/USB mode via MODE pin - eliminates need for external multiplexing or firmware arbitration.
Quasi-pulse charging mode	Reduces thermal stress by leveraging upstream current-limited adapters - cuts on-die power dissipation by >70% vs. linear mode at high ΔV.
Integrated power stage	Monolithic 280–380 mΩ MOSFET + reverse-blocking diode - eliminates 3–4 discrete components and saves PCB area in space-constrained designs.
Programmable safety timers	Configurable max charge time (TPRG) and pre-charge timeout - prevents indefinite charging under fault conditions (e.g., shorted battery).
Real-time battery health monitoring	Combined NTC/PTC interface (TH), battery presence detection (VOSNS/VOUT), and gas-gauge output (IEND) - enables comprehensive BMS-lite functionality without MCU overhead.

Applications

GPS Navigation Devices

USB-Powered Portable Audio

Use Scenario: Compact handheld GPS unit powered by 3.7 V Li-Po battery, charged via mini-USB port or optional AC adapter.

IC Role / Device Role / Timing Role: Primary battery charger managing CC/CV profile, thermal foldback, and USB/AC priority switching.

Use Value: Enables single-chip charging solution with <3 mm² footprint, eliminating discrete MOSFET and sense resistor - critical for ultra-thin enclosures.

Use Scenario: MP3 player with USB-rechargeable battery, requiring low standby current and LED status feedback.

IC Role / Device Role / Timing Role: Linear-mode charger with open-collector ST1/ST2 driving dual-color LED for charge progress indication.

Use Value: Achieves <90 µA shutdown current and direct LED drive - extends shelf life and removes need for LED driver transistors.

Digital Still Cameras

Standalone Battery Chargers

Use Scenario: DSLR accessory battery charger dock accepting both USB-C and barrel-jack AC input.

IC Role / Device Role / Timing Role: Dual-path charger with MODE pin auto-switching and programmable IAC/IUSB resistors for flexible input sourcing.

Use Value: Supports 1 A AC fast-charge and 500 mA USB fallback - meets OEM requirements for multi-standard compatibility.

Use Scenario: Wall-mounted Li-Ion charger for power tools or medical sensors, requiring robust thermal management.

IC Role / Device Role / Timing Role: Quasi-pulse mode charger interfacing with current-limited 12 V adapter to minimize heatsink size.

Use Value: Reduces thermal resistance requirement by 3× vs. linear mode - allows plastic enclosure without metal heat spreaders.

Equivalent & Alternatives

The following parts are listed as comparable options for similar single-cell Li-Ion linear charger applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BQ24075RTWR	TI device uses external MOSFET; no integrated power switch; requires separate R_SENSE and blocking diode.	Lacks monolithic integration - increases BOM count and layout complexity; supports I²C configuration only.	Select when design requires programmable charge parameters via I²C rather than resistor-based analog setup.
MP2617GQZ	MPS part integrates MOSFET but lacks NTC/PTC interface; thermal protection limited to junction sensing only.	No battery temperature monitoring - unsuitable for applications requiring JEITA-compliant charging profiles.	Select for cost-sensitive consumer electronics where ambient temperature control suffices and thermistor interface is unnecessary.

Compared with BQ24075RTWR and MP2617GQZ, the L6924U uniquely combines monolithic power integration, analog-programmable dual-input charging, and full NTC/PTC battery temperature supervision - making it optimal for space-constrained, thermally sensitive portable devices needing minimal external components.

Availability

L6924U is available at Aetrix Electronics and suitable for GPS navigation devices, USB-powered portable audio players, digital still cameras, and standalone battery chargers requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for L6924U 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, mixed-signal, power, and microcontroller solutions for industrial, automotive, and consumer markets.

The L6924U belongs to ST's dedicated battery management IC portfolio, engineered specifically for compact, dual-input Li-Ion charging in portable electronics - emphasizing integration density, thermal resilience, and analog configurability without MCU dependency.

FAQ

What is the minimum input voltage required for L6924U to start charging?

The L6924U has a startup threshold of 4.1 V on the VIN pin, meaning it will not begin operation until input voltage exceeds this level. However, once started, it can sustain charging down to 2.5 V input - enabling quasi-pulse mode operation with current-limited adapters whose output sags under load. This dual-threshold behavior supports both regulated and unregulated sources.

How does the L6924U detect battery presence?

The L6924U detects battery presence using differentiated sensing: it forces a small current through VOUT and monitors the resulting voltage on VOSNS. If VOSNS fails to rise above a threshold (indicating open-circuit or disconnected battery), the IC enters standby mode and disables charging. This method avoids reliance on external comparators or voltage dividers.

Can the L6924U be used with lithium-iron-phosphate (LiFePO₄) batteries?

No - the L6924U is factory-trimmed for 4.2 V ±1% Li-Ion/Li-Polymer termination and lacks user-adjustable output voltage. Its internal reference and regulation loop are fixed; applying it to LiFePO₄ (requiring ~3.6 V termination) would overcharge the cell and create safety hazards. ST does not characterize or guarantee operation outside its specified 4.2 V nominal output.

What is the purpose of the VREF pin, and can it be left unconnected?

VREF outputs a precision 1.8 V ±2% internal reference used by TH, IEND, and internal regulation circuits. It must be decoupled with a 100 nF ceramic capacitor to GND and cannot be left floating - doing so causes instability in temperature monitoring, gas-gauge accuracy, and output voltage regulation. ST specifies 100 nF as mandatory per Section 9.2 of the datasheet.

L6924U Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 16-VFQFN Exposed Pad

Packaging:: Tray

Product Status:: Discontinued at Digi-Key

Battery Chemistry:: Lithium Ion/Polymer

Number of Cells:: 1

Current - Charging:: Constant - Programmable

Programmable Features:: Current, Timer

Fault Protection:: Over Temperature

Charge Current - Max:: 1A

Battery Pack Voltage:: 4.2V

Voltage - Supply (Max):: 12V

Interface:: USB

Operating Temperature:: -40°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-VFQFPN (3x3)

L6924U FAQ

1.How can I place an order for L6924U through Aetrix?

Please submit a Request for Quotation (RFQ) for L6924U 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 L6924U reliable?

The price and inventory of L6924U are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6924U is usually 5 days.

3.What payment methods are accepted for L6924U?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6924U transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L6924U?

L6924U orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L6924U 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 L6924U?

For technical support, including L6924U datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6924U requirements.

6.How does Aetrix verify that L6924U is sourced from the original manufacturer or authorized distributors?

All L6924U 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 L6924U meets industry standards.

7.What is the process for return or replacement of L6924U?

All L6924U units undergo pre-shipment inspection (PSI). If there is an issue with L6924U, 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 L6924U part is unused and in its original packaging.

Return procedure for L6924U:

1.Submit a request within 90 days.

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

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