Current sense amp for 5 V rails
The MAX9919FASA+ is a single-channel current sense amplifier from Maxim Integrated. It operates from a 4.5 V to 5.5 V supply span. Temperature range spans -40°C to 125°C, making it suitable for industrial enclosures, automotive under-hood compartments, and outdoor telecom cabinets. The 8-SOIC with exposed pad (8-SOIC-EP) helps pull heat out through the PCB ground plane when ambient runs high.
Input offset and bias — what they mean for your measurement
Input offset voltage is 400 µV. This part is better suited for higher-side shunt voltages where the offset is a small fraction of the reading. Input bias current is 175 µA, which flows through the shunt and can introduce a small additional voltage drop. In low-side sensing with a low-value shunt, that bias current adds to the load current reading — account for it in the calibration constant.
Package and mounting
Supplied in a tube (not tape-and-reel). The 8-SOIC with exposed pad requires a thermal land on the PCB — the datasheet's recommended footprint includes a pad under the package for solder attachment. Surface-mount only; no through-hole variant.
Lifecycle and compliance
Status is Active per the manufacturer's product listing. ROHS3 compliant — no exemptions that would block EU or California market use.