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BQ2057CDGKR

Active
Texas Instruments

LOW DROPOUT LINEAR 1-CELL LI-ION BATTERY CHARGE CONTROLLER WITH AUTOCOMPTM, 4.2V

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BQ2057CDGKR - https://ti.com/content/dam/ticom/images/products/package/d/dgk0008a.png

BQ2057CDGKR

Active
Texas Instruments

LOW DROPOUT LINEAR 1-CELL LI-ION BATTERY CHARGE CONTROLLER WITH AUTOCOMPTM, 4.2V

Technical Specifications

Parameters and characteristics commom to parts in this series

SpecificationBQ2057CDGKRBQ2057C Series
Battery ChemistryLithium Ion/PolymerLithium Ion/Polymer
Battery Pack Voltage4.2 V4.2 V
Current - ChargingConstant - ProgrammableConstant - Programmable
Mounting TypeSurface MountSurface Mount
Number of Cells11
Operating Temperature [Max]70 °C70 °C
Operating Temperature [Min]-20 °C-20 °C
Package / Case8-TSSOP, 8-MSOP8-TSSOP (0.173", 4.40mm Width), 8-TSSOP, 8-MSOP, 8-SOIC
Package / Case0.118 in0.118 - 3.9 in
Package / Case3 mm3 mm
Programmable FeaturesCurrentCurrent
Supplier Device Package-8-TSSOP, 8-SOIC
Voltage - Supply (Max) [Max]15 V15 V

Pricing

Prices provided here are for design reference only. For realtime values and availability, please visit the distributors directly

BQ2057C Series

Low Dropout linear 1-cell Li-ion battery charge controller with AutoCompTM, 4.2V

PartProgrammable FeaturesCurrent - ChargingNumber of CellsMounting TypeBattery ChemistrySupplier Device PackageOperating Temperature [Min]Operating Temperature [Max]Voltage - Supply (Max) [Max]Battery Pack VoltagePackage / CasePackage / CasePackage / Case
Texas Instruments
BQ2057CTS
The BQ2057 series advanced lithium-ion (Li-ion) and lithium-polymer (Li-pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp™ charge-rate compensation in a single 8-pin IC. MSOP, TSSOP, and SOIC package options are offered to fit a wide range of end applications. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charge until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the BQ2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the BQ2057 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage. The BQ2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating-temperature and supply-voltage ranges. For single and dual cells, the BQ2057 is offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charge stops when the current tapers to the charge termination threshold, I(TERM). The BQ2057 automatically restarts the charge if the battery voltage falls below the V(RCH)threshold. The designer also may use the AutoComp feature to reduce charging time. This proprietary technique allows safe and dynamic compensation for the internal impedance of the battery pack during charge. The BQ2057 series advanced lithium-ion (Li-ion) and lithium-polymer (Li-pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp™ charge-rate compensation in a single 8-pin IC. MSOP, TSSOP, and SOIC package options are offered to fit a wide range of end applications. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charge until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the BQ2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the BQ2057 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage. The BQ2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating-temperature and supply-voltage ranges. For single and dual cells, the BQ2057 is offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charge stops when the current tapers to the charge termination threshold, I(TERM). The BQ2057 automatically restarts the charge if the battery voltage falls below the V(RCH)threshold. The designer also may use the AutoComp feature to reduce charging time. This proprietary technique allows safe and dynamic compensation for the internal impedance of the battery pack during charge.
Current
Constant - Programmable
1
Surface Mount
Lithium Ion/Polymer
8-TSSOP
-20 °C
70 °C
15 V
4.2 V
8-TSSOP (0.173", 4.40mm Width)
Texas Instruments
BQ2057CDGKR
The BQ2057 series advanced lithium-ion (Li-ion) and lithium-polymer (Li-pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp™ charge-rate compensation in a single 8-pin IC. MSOP, TSSOP, and SOIC package options are offered to fit a wide range of end applications. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charge until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the BQ2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the BQ2057 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage. The BQ2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating-temperature and supply-voltage ranges. For single and dual cells, the BQ2057 is offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charge stops when the current tapers to the charge termination threshold, I(TERM). The BQ2057 automatically restarts the charge if the battery voltage falls below the V(RCH)threshold. The designer also may use the AutoComp feature to reduce charging time. This proprietary technique allows safe and dynamic compensation for the internal impedance of the battery pack during charge. The BQ2057 series advanced lithium-ion (Li-ion) and lithium-polymer (Li-pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp™ charge-rate compensation in a single 8-pin IC. MSOP, TSSOP, and SOIC package options are offered to fit a wide range of end applications. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charge until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the BQ2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the BQ2057 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage. The BQ2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating-temperature and supply-voltage ranges. For single and dual cells, the BQ2057 is offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charge stops when the current tapers to the charge termination threshold, I(TERM). The BQ2057 automatically restarts the charge if the battery voltage falls below the V(RCH)threshold. The designer also may use the AutoComp feature to reduce charging time. This proprietary technique allows safe and dynamic compensation for the internal impedance of the battery pack during charge.
Current
Constant - Programmable
1
Surface Mount
Lithium Ion/Polymer
-20 °C
70 °C
15 V
4.2 V
8-MSOP, 8-TSSOP
0.118 in
3 mm
Texas Instruments
BQ2057CTSTR
The BQ2057 series advanced lithium-ion (Li-ion) and lithium-polymer (Li-pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp™ charge-rate compensation in a single 8-pin IC. MSOP, TSSOP, and SOIC package options are offered to fit a wide range of end applications. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charge until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the BQ2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the BQ2057 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage. The BQ2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating-temperature and supply-voltage ranges. For single and dual cells, the BQ2057 is offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charge stops when the current tapers to the charge termination threshold, I(TERM). The BQ2057 automatically restarts the charge if the battery voltage falls below the V(RCH)threshold. The designer also may use the AutoComp feature to reduce charging time. This proprietary technique allows safe and dynamic compensation for the internal impedance of the battery pack during charge. The BQ2057 series advanced lithium-ion (Li-ion) and lithium-polymer (Li-pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp™ charge-rate compensation in a single 8-pin IC. MSOP, TSSOP, and SOIC package options are offered to fit a wide range of end applications. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charge until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the BQ2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the BQ2057 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage. The BQ2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating-temperature and supply-voltage ranges. For single and dual cells, the BQ2057 is offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charge stops when the current tapers to the charge termination threshold, I(TERM). The BQ2057 automatically restarts the charge if the battery voltage falls below the V(RCH)threshold. The designer also may use the AutoComp feature to reduce charging time. This proprietary technique allows safe and dynamic compensation for the internal impedance of the battery pack during charge.
Current
Constant - Programmable
1
Surface Mount
Lithium Ion/Polymer
8-TSSOP
-20 °C
70 °C
15 V
4.2 V
8-TSSOP (0.173", 4.40mm Width)
Texas Instruments
BQ2057CSNTR
The BQ2057 series advanced lithium-ion (Li-ion) and lithium-polymer (Li-pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp™ charge-rate compensation in a single 8-pin IC. MSOP, TSSOP, and SOIC package options are offered to fit a wide range of end applications. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charge until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the BQ2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the BQ2057 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage. The BQ2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating-temperature and supply-voltage ranges. For single and dual cells, the BQ2057 is offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charge stops when the current tapers to the charge termination threshold, I(TERM). The BQ2057 automatically restarts the charge if the battery voltage falls below the V(RCH)threshold. The designer also may use the AutoComp feature to reduce charging time. This proprietary technique allows safe and dynamic compensation for the internal impedance of the battery pack during charge. The BQ2057 series advanced lithium-ion (Li-ion) and lithium-polymer (Li-pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp™ charge-rate compensation in a single 8-pin IC. MSOP, TSSOP, and SOIC package options are offered to fit a wide range of end applications. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charge until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the BQ2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the BQ2057 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage. The BQ2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating-temperature and supply-voltage ranges. For single and dual cells, the BQ2057 is offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charge stops when the current tapers to the charge termination threshold, I(TERM). The BQ2057 automatically restarts the charge if the battery voltage falls below the V(RCH)threshold. The designer also may use the AutoComp feature to reduce charging time. This proprietary technique allows safe and dynamic compensation for the internal impedance of the battery pack during charge.
Current
Constant - Programmable
1
Surface Mount
Lithium Ion/Polymer
8-SOIC
-20 °C
70 °C
15 V
4.2 V
8-SOIC
3.9 mm
Texas Instruments
BQ2057CSN
The BQ2057 series advanced lithium-ion (Li-ion) and lithium-polymer (Li-pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp™ charge-rate compensation in a single 8-pin IC. MSOP, TSSOP, and SOIC package options are offered to fit a wide range of end applications. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charge until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the BQ2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the BQ2057 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage. The BQ2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating-temperature and supply-voltage ranges. For single and dual cells, the BQ2057 is offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charge stops when the current tapers to the charge termination threshold, I(TERM). The BQ2057 automatically restarts the charge if the battery voltage falls below the V(RCH)threshold. The designer also may use the AutoComp feature to reduce charging time. This proprietary technique allows safe and dynamic compensation for the internal impedance of the battery pack during charge. The BQ2057 series advanced lithium-ion (Li-ion) and lithium-polymer (Li-pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp™ charge-rate compensation in a single 8-pin IC. MSOP, TSSOP, and SOIC package options are offered to fit a wide range of end applications. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charge until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the BQ2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the BQ2057 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage. The BQ2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating-temperature and supply-voltage ranges. For single and dual cells, the BQ2057 is offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charge stops when the current tapers to the charge termination threshold, I(TERM). The BQ2057 automatically restarts the charge if the battery voltage falls below the V(RCH)threshold. The designer also may use the AutoComp feature to reduce charging time. This proprietary technique allows safe and dynamic compensation for the internal impedance of the battery pack during charge.
Current
Constant - Programmable
1
Surface Mount
Lithium Ion/Polymer
8-SOIC
-20 °C
70 °C
15 V
4.2 V
8-SOIC
3.9 mm
Texas Instruments
BQ2057CDGK
The BQ2057 series advanced lithium-ion (Li-ion) and lithium-polymer (Li-pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp™ charge-rate compensation in a single 8-pin IC. MSOP, TSSOP, and SOIC package options are offered to fit a wide range of end applications. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charge until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the BQ2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the BQ2057 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage. The BQ2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating-temperature and supply-voltage ranges. For single and dual cells, the BQ2057 is offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charge stops when the current tapers to the charge termination threshold, I(TERM). The BQ2057 automatically restarts the charge if the battery voltage falls below the V(RCH)threshold. The designer also may use the AutoComp feature to reduce charging time. This proprietary technique allows safe and dynamic compensation for the internal impedance of the battery pack during charge. The BQ2057 series advanced lithium-ion (Li-ion) and lithium-polymer (Li-pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp™ charge-rate compensation in a single 8-pin IC. MSOP, TSSOP, and SOIC package options are offered to fit a wide range of end applications. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charge until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the BQ2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the BQ2057 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage. The BQ2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating-temperature and supply-voltage ranges. For single and dual cells, the BQ2057 is offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charge stops when the current tapers to the charge termination threshold, I(TERM). The BQ2057 automatically restarts the charge if the battery voltage falls below the V(RCH)threshold. The designer also may use the AutoComp feature to reduce charging time. This proprietary technique allows safe and dynamic compensation for the internal impedance of the battery pack during charge.
Current
Constant - Programmable
1
Surface Mount
Lithium Ion/Polymer
-20 °C
70 °C
15 V
4.2 V
8-MSOP, 8-TSSOP
0.118 in
3 mm

Description

General part information

BQ2057C Series

The BQ2057 series advanced lithium-ion (Li-ion) and lithium-polymer (Li-pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoComp™ charge-rate compensation in a single 8-pin IC. MSOP, TSSOP, and SOIC package options are offered to fit a wide range of end applications.

The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the BQ2057 inhibits charge until the battery temperature is within user-defined thresholds. The BQ2057 then charges the battery in three phases: conditioning, constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V(min), the BQ2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the BQ2057 applies a constant current to the battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage.

The BQ2057 then begins the constant-voltage phase. The accuracy of the voltage regulation is better than ±1% over the operating-temperature and supply-voltage ranges. For single and dual cells, the BQ2057 is offered in four fixed-voltage versions: 4.1 V, 4.2 V, 8.2 V, and 8.4 V. Charge stops when the current tapers to the charge termination threshold, I(TERM). The BQ2057 automatically restarts the charge if the battery voltage falls below the V(RCH)threshold.