My Inquiry
My Account
STMicroelectronics GG25LJ
- Part No.:
- GG25LJ
- Manufacturer:
- STMicroelectronics
- Category:
- Battery Management
- Package:
- 10-WFBGA, FCCSP
- Datasheet:
-
GG25LJ.pdf
- Description:
- IC BATT MON GAS GAUGE 10FCCSP
- Quantity:
- Payment:
- Shipping:
Inventory:1,599
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
GG25LJ from STMicroelectronics is a dedicated gas gauge IC for single-cell Li-ion/Li-polymer batteries, implementing Coulomb counting and voltage-mode state-of-charge (SOC) estimation with 0.25% battery voltage accuracy, ±0.5% full-range voltage measurement, and programmable low-SOC/low-voltage alarm output. It operates in mixed or voltage-only mode, supports battery swap detection, and integrates an internal temperature sensor for compensation.
For engineers reviewing the GG25LJ datasheet, GG25LJ pinout, GG25LJ application, or GG25LJ equivalent, key selection considerations include its 1.4 × 2.0 mm CSP-12 package, I²C interface, 45 µA power-saving mode current, 32.768 kHz internal oscillator, and dual-alarm threshold programming via REG_SOC_ALM and REG_ALARM_VOLTAGE registers.
Technical Context
The GG25LJ implements a hybrid gas gauge architecture combining a 14-bit sigma-delta ADC-based Coulomb counter with a voltage-mode algorithm using a built-in high-precision OCV curve. Its mixed-mode operation dynamically selects between current-sensing (every 4 s) and voltage/temperature sampling (every 4 s / 16 s) to balance accuracy and power.
It features robust power-up OCV measurement with debounce delay, battery swap detection via BATD/CD pin with 1 s UVLO hysteresis, and open-drain ALM output with software-clearable interrupt latching. All register access and configuration occur over a standard I²C interface compliant with 400 kHz Fast Mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Voltage Accuracy | ±0.25% at 25 °C; enables precise SOC estimation from OCV without external calibration |
| Operating Current | 45 µA in power-saving mode; allows >1-year runtime on small coin-cell backup in wearable standby |
| ADC Resolution | 14-bit sigma-delta; delivers 5.88 µV LSB for current sensing and 2.20 mV LSB for voltage measurement |
| Alarm Output | Open-drain ALM pin with programmable SOC (0.5% steps) and voltage (17.6 mV steps) thresholds |
| Temperature Sensing | Internal sensor with ±3 °C accuracy over –40 to +85 °C; eliminates need for external thermistor |
| I²C Interface | Fast Mode (400 kHz); supports standard address 0x55 and register-based configuration of all gas gauge parameters |
| Package | CSP-12 (1.4 × 2.0 mm, 0.4 mm pitch); enables ultra-compact integration in space-constrained wearables |
Pinout & Package
GG25LJ uses a 1.4 × 2.0 mm, 10-bump CSP package (CSP-12 footprint with 2 NC bumps). The device has 10 functional terminals arranged in a 3×4 bump array with two no-connect positions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ALM (Pin 1, A1) | Open-drain alarm output | Drives low when SOC < REG_SOC_ALM or VIN < REG_ALARM_VOLTAGE; requires external pull-up |
| SDA (Pin 2, B1) | I²C bidirectional data line | Open-drain, supports standard/fast-mode I²C; shares bus with other peripherals |
| SCL (Pin 3, C1) | I²C clock input | Drives clock for register read/write; synchronizes all I²C transactions |
| GND (Pin 4, D1) | Analog/digital ground reference | Common return for voltage sensing, current sense, and digital logic; must be low-impedance |
| CG (Pin 6, D3) | Current sense analog input | Accepts ±40 mV differential voltage across external sense resistor; connects to sigma-delta ADC |
| RSTIO (Pin 7, C3) | Reset sense/control I/O | Input detects system reset; output asserts charge inhibit during battery swap or fault |
| BATD/CD (Pin 8, B2) | Battery detect/charge inhibit | Input detects battery presence (>1.61 V); output disables charging during swap or undervoltage |
| VCC (Pin 9, B3) | Power supply input | 2.7–4.5 V operation; powers analog and digital blocks; includes 2.6 V UVLO with 100 mV hysteresis |
| VIN (Pin 10, A3) | Battery voltage input | 0–4.5 V range; feeds voltage-mode algorithm and OCV estimation; filtered via optional R1/C2 |
Key Features
| Feature | Design Value |
|---|---|
| OptimGauge™ algorithm | Combines Coulomb counting and voltage-mode estimation to eliminate long-term SOC drift and compensate for battery aging |
| Programmable dual alarm | Independent SOC (%) and voltage (V) thresholds allow staged low-battery warnings-e.g., 5% SOC alert followed by 3.0 V cutoff |
| Battery swap detection | 1 s UVLO filter on BATD/CD pin prevents false triggers from mechanical bounce; initiates clean OCV re-measurement on insertion |
| Low-power mixed-mode operation | Switches automatically between high-accuracy mixed mode (100 µA) and ultra-low-power voltage mode (45 µA) based on system activity |
| Integrated temperature sensing | On-die sensor with ±3 °C accuracy eliminates external components and improves OCV/SOC correlation across operating temperature |
Applications
| Fitness Tracker | Smart Hearing Aid |
|---|---|
|
Use Scenario: Continuous motion tracking with Bluetooth LE transmission every 5 seconds and accelerometer wake-on-motion. IC Role / Device Role / Timing Role: Primary gas gauge providing real-time SOC to firmware; triggers ALM at 10% to initiate graceful shutdown before deep discharge. Use Value: 0.25% voltage accuracy ensures ±1.5% SOC error at 3.7 V, extending usable runtime by 8–12 minutes versus lower-accuracy gauges. |
Use Scenario: Miniaturized rechargeable hearing aid with 30-hour battery life, requiring precise end-of-life prediction to avoid sudden mute during conversation. IC Role / Device Role / Timing Role: Voltage-mode gas gauge running in 4 s cycles; ALM pin drives haptic alert at 3% SOC while maintaining sub-50 µA average current. Use Value: Internal temperature compensation corrects for ear-canal thermal drift, reducing SOC error from ±5% to ±1.2% across 25–40 °C ambient. |
| Portable ECG Monitor | Wireless Pulse Oximeter |
|
Use Scenario: Clinical-grade handheld ECG device performing 30-second recordings on demand, with USB-C charging and 7-day standby. IC Role / Device Role / Timing Role: Mixed-mode gas gauge: activates Coulomb counting only during recording; reverts to voltage mode during idle to conserve power. Use Value: Dual-alarm capability enables early warning (7% SOC) for user notification and hard cutoff (2% SOC) to preserve firmware integrity and flash retention. |
Use Scenario: Single-use disposable pulse oximeter with CR2032 primary cell, requiring accurate remaining-life indication for clinical confidence. IC Role / Device Role / Timing Role: Voltage-mode gas gauge with fixed 4 s OCV sampling; ALM pin directly drives LED indicator without MCU intervention. Use Value: 1.4 × 2.0 mm CSP package fits within 8 mm × 8 mm PCB area constraint, enabling <12 g total device weight. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar battery fuel gauge applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BQ27426 (TI) | Higher integration: integrated sense resistor, 1% voltage accuracy, but larger 2.5 × 2.5 mm DSBGA-15 package | Requires no external current sense resistor; better for cost-sensitive designs where board space >1.4 mm² is available | Select for simplified BOM if 0.25% voltage accuracy is not required and 2.5 mm² footprint is acceptable |
| MAX17048 (Maxim) | ModelGauge m3 algorithm; 3.5 µA standby current; no internal temperature sensor - requires external thermistor | Lower quiescent current ideal for multi-year primary battery applications; lacks integrated thermal compensation | Select for ultra-low-power primary-cell use cases where external temperature sensing is feasible and SOC drift tolerance >2% |
Compared with BQ27426 and MAX17048, GG25LJ uniquely balances ultra-small CSP footprint, best-in-class 0.25% voltage accuracy, and integrated temperature sensing - making it optimal for space-constrained, rechargeable wearable systems demanding high SOC fidelity without added components.
Availability
GG25LJ is available at Aetrix Electronics and suitable for fitness trackers, portable medical monitors, smart hearing aids, and wireless pulse oximeters requiring stable component supply and long-term lifecycle support.
Supply support for GG25LJ 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 specializing in microcontrollers, analog ICs, and power management solutions for industrial, automotive, and consumer markets.
The GG25LJ belongs to ST's OptimGauge™ family of battery fuel gauges, designed specifically for compact, low-power wearable and portable medical devices requiring high-accuracy SOC estimation without external sensors or calibration.
FAQ
What is the default ALM pin behavior after power-on reset?
At power-up or reset, the ALM pin is high-impedance until the first OCV measurement completes (~250 ms). Then, if SOC falls below the default 1% threshold (REG_SOC_ALM = 2) or VIN drops below 3.00 V (REG_ALARM_VOLTAGE = 170), the pin is driven low. The alarm remains latched until software clears the ALM_SOC or ALM_VOLT bit in REG_CTRL.
How does the GG25LJ handle battery swap detection without false triggers?
The GG25LJ uses a 1-second debounce window on the BATD/CD pin: a voltage drop below 1.61 V must persist ≥1 s to trigger battery swap detection. This filters out mechanical contact bounce and transient dips, ensuring restart only occurs on genuine battery replacement - verified per Figure 9 in the datasheet.
Can the GG25LJ operate without an external current sense resistor?
Yes. When VMODE = 1 (voltage-only mode), the GG25LJ disables the Coulomb counter and relies solely on the voltage-mode algorithm. In this configuration, CG pin is unused, and the device consumes only 45 µA - ideal for applications where current measurement is unnecessary or board space prohibits a sense resistor.
What is the role of the RSTIO pin beyond reset signaling?
RSTIO serves dual functions: as an input, it detects system-level reset events; as an open-drain output, it asserts charge inhibit (active-high) during battery swap or UVLO conditions. This prevents unsafe charging attempts when battery connection is unstable - a hardware-level safety feature independent of I²C control.
GG25LJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- OptimGauge™
- Package/Case:
- 10-WFBGA, FCCSP
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Battery Monitor
- Battery Chemistry:
- -
- Number of Cells:
- -
- Fault Protection:
- -
- Interface:
- I2C
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-FCCSP (1.37x2.01)
GG25LJ FAQ
1.How can I place an order for GG25LJ through Aetrix?
Please submit a Request for Quotation (RFQ) for GG25LJ 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 GG25LJ reliable?
The price and inventory of GG25LJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for GG25LJ is usually 5 days.
3.What payment methods are accepted for GG25LJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for GG25LJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for GG25LJ?
GG25LJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your GG25LJ 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 GG25LJ?
For technical support, including GG25LJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your GG25LJ requirements.
6.How does Aetrix verify that GG25LJ is sourced from the original manufacturer or authorized distributors?
All GG25LJ 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 GG25LJ meets industry standards.
7.What is the process for return or replacement of GG25LJ?
All GG25LJ units undergo pre-shipment inspection (PSI). If there is an issue with GG25LJ, 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 GG25LJ part is unused and in its original packaging.
Return procedure for GG25LJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
GG25LJ Tags
-
BQ29700DSER
Texas Instruments
-
S-8241ABKMC-GBKT2G
ABLIC Inc.
-
S-8241ABPMC-GBPT2G
ABLIC Inc.
-
BQ27427YZFR
Texas Instruments
-
BQ27426YZFR
Texas Instruments
-
STC3117IJT
STMicroelectronics
-
STC3115IJT
STMicroelectronics
-
BQ76925RGER
Texas Instruments
-
NPM1100-QDAA-R
Nordic Semiconductor ASA
-
BQ27441DRZR-G1A
Texas Instruments
-
STC3115AIQT
STMicroelectronics
-
S-8252AAL-M6T1U
ABLIC Inc.
Tech Hub
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
