The MAX471/MAX472 are complete, bidirectional, highside current-sense amplifiers for portable PCs, telephones, and other systems where battery/DC power-line monitoring is critical. High-side power-line monitoring is especially useful in battery-powered systems, since it does not interfere with the ground paths of the battery chargers or monitors often found in “smart” batteries.
The MAX471 has an internal 35mΩ current-sense resistor and measures battery currents up to ±3A. For applications requiring higher current or increased flexibility, the MAX472 functions with external sense and gain-setting resistors. Both devices have a current output that can be converted to a ground-referred voltage with a single resistor, allowing a wide range of battery voltages and currents.
An open-collector SIGN output indicates current-flow direction, so the user can monitor whether a battery is being charged or discharged. Both devices operate from 3V to 36V, draw less than 100µA over temperature, and include a 18µA max shutdown mode.
- Complete High-Side Current Sensing
- Precision Internal Sense Resistor (MAX471)
- 2% Accuracy Over Temperature
- Monitors Both Charge and Discharge
- 3A Sense Capability with Internal Sense Resistor (MAX471)
- Higher Current-Sense Capability with External Sense Resistor (MAX472)
- 100µA Max Supply Current
- 18µA Max Shutdown Mode
- 3V to 36V Supply Operation
- 8-Pin DIP/SO Packages
Specifications
