Precision current monitor in a SOT-23-5 footprint
The MAX9938FEUK+T is a single-channel current sense amplifier from Analog Devices, designed to measure load current by amplifying the voltage drop across an external shunt resistor. Its 60 kHz bandwidth captures DC and low-frequency AC current profiles, making it suitable for monitoring supply rails, battery charge/discharge cycles, and motor winding currents where the signal content sits below that corner. Operating from a supply span of 1.6 V to 28 V, the device can be powered directly from the monitored rail or a separate bias supply, simplifying system-level power budgeting. The 1.1 µA quiescent current keeps the self-consumption negligible in battery-powered equipment — a sensor node drawing 10 µA in sleep mode sees only an 11 % overhead from the monitor itself.
Input offset and measurement floor
The 100 µV maximum input offset voltage sets the lower bound on resolvable shunt voltage. For a 10 mΩ shunt, 100 µV corresponds to a 10 mA offset error at the output — a figure that matters when the full-scale current is below 1 A and the error budget is tight. The offset is trimmed at the factory; no external nulling is required.
Industrial temperature range and package integration
The SOT-23-5 package occupies approximately 3 mm × 3 mm of board area, with a 0.95 mm pitch that routes cleanly on a two-layer PCB without via fan-out. Surface-mount assembly is standard for this footprint class. The tape-and-reel delivery supports automated pick-and-place at volumes from prototype reels to production quantities.