0.1V to +28V Input Range, Micropower, Uni-/Bidirectional, Current-Sense Amplifiers

The MAX9928F/MAX9929F low-cost, uni-/bidirectional, high-side, current-sense amplifiers are ideal for monitoring battery charge and discharge currents in notebooks, cell phones, and other portable equipment. These devices feature a wide -0.1V to +28V input common-mode voltage range, low 20µA supply current with VOS less than 0.4mV, and a gain accuracy better than 1.0%. The input common-mode range is independent of the supply voltage, ensuring that the current-sense information remains accurate even when the measurement rail is shorted to ground.

The MAX9928F features a current output with a transconductance ratio of 5μA/mV. An external resistor converts the output current to a voltage, allowing adjustable gain so that the input sense voltage can be matched to the maximum ADC input swing. The MAX9929F has a voltage output and integrates a 10kΩ output resistor for a fixed voltage gain of 50V/V.

A digital SIGN output indicates direction of current flow, so the user can utilize the full ADC input range for measuring both charging and discharging currents.

The MAX9928F/MAX9929F are fully specified over the -40°C to +125°C automotive temperature range, and available in 6-bump UCSP™ (1mm x 1.5mm) and 8-pin µMAX® packages. The UCSP package is bump-to-bump compatible with the MAX4372EBT.

Applications

* General-System/Board-Level Current Monitoring * Monitoring Charge/Discharge Currents in Portable/Battery-Powered Systems * Notebook Computers * Precision Current Sources * Smart-Battery Packs/Chargers * Smart-Cell Phones * Super Capacitor Charge/Discharge

* Wide -0.1V to +28V Common-Mode Range, Independent of Supply Voltage

* 2.5V to 5.5V Operating Supply Voltage

* 20µA Quiescent Supply Current

* 0.4mV (max) Input Offset Voltage

* Gain Accuracy Better than 1% (max)

* SIGN Output Indicates Current Polarity

* Transconductance and Gain Versions Available

* 5µA/mV (MAX9928F)

* 50V/V (MAX9929F)

* Pin Compatible with the MAX4372 in UCSP

* Available in Ultra-Small, 3x2 UCSP (1mm x 1.5mm) and 8-Pin µMAX Packages