The MAX4069–MAX4072 low-cost, bidirectional, high-side, 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
- Cell Phone Battery-Current Monitoring
- Motor Control
- Notebook Fuel Gauging
- Power-Management Systems
- Smart Battery Packs/Chargers
