The MAX9928/MAX9929 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/MAX9928T feature a current output with transconductance ratios of 5µA/mV and 2µA/mV, respectively. 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/MAX9929T have a voltage output and integrate a 10kΩ output resistor for fixed voltage gains of 50V/V and 20V/V, respectively.
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 MAX9928/MAX9929 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 MAX4372_EBT.
Key Features
Applications/Uses
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
Two IOUT Transconductance Versions Available
2µA/mV (MAX9928T)
5µA/mV (MAX9928F)
Two VOUT Gain Versions Available
20V/V (MAX9929T)
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
General-System/Board-Level Current Monitoring
Monitoring Charge/Discharge Currents in Portable/Battery-Powered Systems
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