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Battery charger ICs

BQ21040

ACTIVE

1-cell, 0.8-A Li-ion and Li-polymer battery charger

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Data sheet

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Same functionality with different pin-out to the compared device
BQ25170 ACTIVE 800-mA linear battery charger for 1-cell Li-ion and LiFePO4 BQ25170 comes with lower quiescent current and flexible charge voltage.

BQ21040

ACTIVE
Data sheet Order now

Product details

Number of series cells 1 Charge current (max) (A) 0.8 Vin (max) (V) 6.45 Cell chemistry Li-Ion/Li-Polymer Battery charge voltage (min) (V) 4.2 Battery charge voltage (max) (V) 4.2 Absolute max Vin (max) (V) 30 Control topology Linear Control interface Standalone (RC-Settable) Features BAT temp thermistor monitoring (hot/cold profile), Input OVP Vin (min) (V) 3.5 Rating Catalog Operating temperature range (°C) 0 to 125
Number of series cells 1 Charge current (max) (A) 0.8 Vin (max) (V) 6.45 Cell chemistry Li-Ion/Li-Polymer Battery charge voltage (min) (V) 4.2 Battery charge voltage (max) (V) 4.2 Absolute max Vin (max) (V) 30 Control topology Linear Control interface Standalone (RC-Settable) Features BAT temp thermistor monitoring (hot/cold profile), Input OVP Vin (min) (V) 3.5 Rating Catalog Operating temperature range (°C) 0 to 125
SOT-23 (DBV) 6 8.12 mm² 2.9 x 2.8
  • Charging
    • 1% Charge Voltage Accuracy
    • 10% Charge Current Accuracy
    • Low Battery Leakage Current (1 µA)
    • Programmable Charge Current using External Resistor up to 800 mA
    • 4.2-V Li-Ion and Li-Pol Charger
  • Protection
    • 30-V Input Rating; with 6.6-V Input Overvoltage Protection
    • Input Voltage Dynamic Power Management
    • 125°C Thermal Regulation; 150°C Thermal Shutdown Protection
    • OUT Short-Circuit Protection and ISET Short Detection
    • Overtemperature Sensing Protection Through NTC
    • Fixed 10-Hour Safety Timer
  • System
    • Status Indication – Charging/Done
    • Available in Small SOT-23 Package
  • Charging
    • 1% Charge Voltage Accuracy
    • 10% Charge Current Accuracy
    • Low Battery Leakage Current (1 µA)
    • Programmable Charge Current using External Resistor up to 800 mA
    • 4.2-V Li-Ion and Li-Pol Charger
  • Protection
    • 30-V Input Rating; with 6.6-V Input Overvoltage Protection
    • Input Voltage Dynamic Power Management
    • 125°C Thermal Regulation; 150°C Thermal Shutdown Protection
    • OUT Short-Circuit Protection and ISET Short Detection
    • Overtemperature Sensing Protection Through NTC
    • Fixed 10-Hour Safety Timer
  • System
    • Status Indication – Charging/Done
    • Available in Small SOT-23 Package

The bq21040 device is a highly integrated Li-Ion and Li-Pol linear battery charger device targeted at space-limited portable applications. The device operates from either a USB port or AC adapter. The high input voltage range with input overvoltage protection supports low-cost unregulated adapters.

The bq21040 has a single power output that charges the battery. A system load can be placed in parallel with the battery as long as the average system load does not keep the battery from charging fully during the 10 hour safety timer.

The battery is charged in three phases: conditioning, constant current and constant voltage. In all charge phases, an internal control loop monitors the IC junction temperature and reduces the charge current if an internal temperature threshold is exceeded.

The charger power stage and charge current sense functions are fully integrated. The charger function has high accuracy current and voltage regulation loops, charge status display, and charge termination. The pre-charge current and termination current threshold are fixed to 20% and 10%, respectively. The fast charge current value is programmable through an external resistor.

The bq21040 device is a highly integrated Li-Ion and Li-Pol linear battery charger device targeted at space-limited portable applications. The device operates from either a USB port or AC adapter. The high input voltage range with input overvoltage protection supports low-cost unregulated adapters.

The bq21040 has a single power output that charges the battery. A system load can be placed in parallel with the battery as long as the average system load does not keep the battery from charging fully during the 10 hour safety timer.

The battery is charged in three phases: conditioning, constant current and constant voltage. In all charge phases, an internal control loop monitors the IC junction temperature and reduces the charge current if an internal temperature threshold is exceeded.

The charger power stage and charge current sense functions are fully integrated. The charger function has high accuracy current and voltage regulation loops, charge status display, and charge termination. The pre-charge current and termination current threshold are fixed to 20% and 10%, respectively. The fast charge current value is programmable through an external resistor.
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Technical documentation

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Type Title Date
* Data sheet bq21040 0.8-A, Single-Input, Single Cell Li-Ion and Li-Pol Battery Charger datasheet (Rev. D) PDF | HTML 08 Jan 2019
Application note Temperature Sensing Without an Adaptor Present on the BQ21040 PDF | HTML 15 Sep 2022
Application note BQ2404x, BQ2405x, and BQ2409x Frequently Asked Questions 25 Feb 2019
Analog Design Journal 2Q 2016 Analog Applications Journal Issue 26 Apr 2016
Analog Design Journal Battery-charging considerations for low-power applications 26 Apr 2016
EVM User's guide bq21040 0.8-A Single-Input, Single-Cell Li-Ion Battery Charger EVM User's Guide 21 Mar 2016

Design & development

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Evaluation board

BQ21040EVM-777 — BQ21040 0.8-A Single-Input Single-Cell Li-Ion Battery Charger Evaluation Module

The bq2404x series of devices are highly integrated Li-ion linear charger devices targeted at space-limited portable applications. The devices operate from either a USB port or AC adapter and has a single power output that charges the battery. A system load can be placed in parallel with the (...)
User guide: PDF
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SOT-23 (DBV) 6 Ultra Librarian
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