What the key parametrics mean for the signal chain
The MAX406AESA+: The 8 kHz gain-bandwidth product and 0.005 V/µs slew rate define the usable signal bandwidth. For gains of 10 or 100, the closed-loop bandwidth falls to 800 Hz and 80 Hz respectively — adequate for DC or quasi-DC measurements from thermocouples, strain gauges, or photodiodes, but not for audio or fast ADC driving. The 0.1 pA input bias current and 250 µV input offset voltage let it interface directly with high-impedance sensors without a separate buffer stage. Rail-to-rail output swing means the output can drive within millivolts of the supply rails, preserving dynamic range in a single-supply 3 V or 5 V system. The 600 µA per-channel output current is modest — enough to drive a reference input or a low-power ADC, but not a headphone or relay coil.