Low-Cost, Precision, High-Side Current-Sense Amplifier

The MAX4172 is a low-cost, precision, high-side current-sense amplifier 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 battery charger's ground path. Wide bandwidth and ground-sensing capability make the MAX4172 suitable for closed-loop battery-charger and general-purpose current-source applications. The 0 to 32V input common-mode range is independent of the supply voltage, which ensures that current-sense feedback remains viable, even when connected to a battery in deep discharge.

To provide a high level of flexibility, the MAX4172 functions with an external sense resistor to set the range of load current to be monitored. It has a current output that can be converted to a ground-referred voltage with a single resistor, accommodating a wide range of battery voltages and currents.

An open-collector power-good output (active-low PG) indicates when the supply voltage reaches an adequate level to guarantee proper operation of the current-sense amplifier. The MAX4172 operates with a 3.0V to 32V supply voltage, and is available in a space-saving, 8-pin µMAX® or SO package.

Applications

* Battery-Powered Applications * Closed-Loop Battery Chargers/Current Sources * Energy Management * Portable PCs: Notebooks, Subnotebooks, Palmtops * Portable Test/Measurement Systems * Portable/Cellular Phones * Smart Battery Packs/Chargers

* Ideal for High-Side Monitoring

* 3V to 32V Supply Operation

* ±0.5% Typical Full-Scale Accuracy Over Temperature

* High Accuracy +2V to +32V Common-Mode Range, Functional Down to 0V, Independent of Supply Voltage

* 800kHz Bandwidth [VSENSE = 100mV (1C)]

* 200kHz Bandwidth [VSENSE = 6.25mV (C/16)]

* Minimizes Board Space Requirements

* µMAX and SO Packages