Precision measurement front-end in a compact SSOP
The MAX1402CAI+ is an 18-bit sigma-delta ADC with a built-in programmable gain amplifier (PGA) and input multiplexer, configured as MUX-PGA-ADC. This architecture handles low-level sensor signals directly — thermocouples, strain gauges, or bridge outputs — without an external instrumentation amplifier. It accepts up to five inputs in pseudo-differential mode or three in full differential mode, giving flexibility to scan multiple channels while maintaining common-mode rejection on each.
Sampling rate and signal bandwidth trade-off
The ADC samples at 480 S/s — a rate suited to DC or low-frequency measurements where noise rejection from the sigma-delta modulator's oversampling is the priority. For a 50/60 Hz line-frequency application, the digital filter can be set to notch out the mains fundamental and its harmonics without additional analog filtering. The SPI data interface keeps the digital side clean — four wires (SCLK, DIN, DOUT, CS) are all that is needed to connect to a microcontroller or DSP core.
Housed in a 28-pin SSOP (0.209-inch body width, 5.30 mm), surface-mount. The 0.65 mm pitch is standard for this package class — two-layer boards route it cleanly with 10/10 mil trace/space rules. Supplied in tube packaging, suitable for hand-assembly or low-volume pick-and-place without reel changeover.