What the 125 kHz bandwidth and 1.1 µA supply mean for your BOM
The MAX9938TEUK+T is a single-circuit current sense amplifier from Analog Devices, packaged in a SOT-23-5. Its 125 kHz bandwidth limits it to DC and low-frequency current monitoring — think battery charge/discharge profiles, power-supply output tracking, or motor phase currents at fundamental frequency, not high-speed switching edges. Drawing just 1.1 µA from the supply, this part is sized for always-on monitoring in battery-powered gear — a sensor node logging current every few seconds sees the amplifier's own draw as a negligible fraction of the system sleep current.
Supply range and temperature grade — where it fits
Input offset voltage is 100 µV typical, which sets the floor on measurement accuracy at low shunt voltages — a 10 mΩ shunt carrying 100 mA drops only 1 mV, so the offset contributes a 10% error at that point; a larger shunt or higher sense voltage improves the ratio.