Direct measurements of battery stacks ranging in output from 3.6 to 20 V are possible with the Linear Technology’s LTC2943 multicell battery gas gauge. Minimized power consumption and high measurement accuracy is due to the eradication of level-shifting on the supply, and the fact that measurement pins aren’t required to interface with multicell voltages. Employing a 14-bit analog-to-digital converter, the gauge measures charge, voltage, and temperature within 1% accuracy to assess a battery’s state of charge (SoC). Battery current is measured by monitoring the voltage across an external, high-side sense resistor and integrating this information to infer charge. A bidirectional analog integrator accommodates either current polarity (battery charge or discharge), and a programmable prescaler allows for various battery capacities. The host system receives data via an I2C/SMBus-compatible, two-wire interface that also is used to configure the gas gauge. The host can program high and low thresholds for all measured parameters. If tripped, it can signal an alert with the SMBus alert protocol or by setting a register flag. Operating temperature ranges from 0 to 70°C (commercial version) and −40 to 85°C (industrial version). The LTC2943 comes in an 8-pin, 3- by 3-mm DFN package.