Current sense amp in an 8-MSOP
The AD8418ABRMZ-RL is a single-channel current sense amplifier from Analog Devices, in an 8-MSOP package. It measures the voltage drop across a shunt resistor and outputs a proportional voltage — the basic job of sensing load current in a power rail or motor phase. The 4.1 mA supply current is the quiescent draw; the input bias current is 130 µA, which flows through the shunt and adds a small offset error — factor it into the shunt value calculation.
The -3 dB bandwidth is 250 kHz, and the slew rate is 1 V/µs. Together they set the fastest current transient the amplifier can track: a step change in load current will be reproduced at the output with a rise time of roughly 350 ns (0.35 / bandwidth). For switching frequencies up to a few tens of kHz, the output settles within one cycle; above that the amplitude rolls off.
A current-sense amp in an engine-bay ECU or a factory-floor motor drive sees this range; the 8-MSOP plastic package handles the thermal cycling without issue.