The MAX4069–MAX4072 low-cost, bidirectional, highside,
current-sense amplifiers are ideal for monitoring
battery charge and discharge currents in notebooks,
cell phones, and other portable equipment. They feature
up to 24V input common-mode voltage range, low
100μA supply current (which drops to only 10μA in
shutdown), and a total output error of less than 1.5%.
The wide 1.35V to 24V input common-mode range is
independent of the supply voltage, ensuring that the
current-sense feedback remains accurate even when
connected to a battery pack in deep discharge.
To achieve maximum flexibility, an external current-sense
resistor is used along with a Gain Select pin to choose
either 50V/V or 100V/V. A single output pin continuously
monitors the transition from charge to discharge and
avoids the need for a separate polarity output. The
MAX4070 contains an internal 2.5V reference. The
charging current is represented by an output voltage
from 2.5V to VCC, while discharge current is given from
2.5V to GND. The MAX4071 is similar, but with a reference
voltage of 1.5V. The MAX4069 has an adjustable
reference voltage, set by two external resistors. The
MAX4072 has an input for an external reference.
The MAX4069/MAX4071/MAX4072 operate from a 2.7V to
24V single supply. The MAX4070 operates from a 3.6V to
24V single supply. All devices are specified over the
automotive operating temperature range, -40°C to
+125°C. The MAX4070/MAX4071/MAX4072 are available
in 8-pin μMAX and 8-pin thin QFN packages. The
MAX4069 is available in a 10-pin μMAX package.
Applications
Notebook Fuel Gauging
Smart-Battery Packs/Chargers
Motor Control
Power-Management Systems
Cell-Phone Battery-Current Monitoring