18-bit Sigma-Delta ADC with PGA — what it does and where it fits
The Analog Devices MAX1400CAI+ is an 18-bit Sigma-Delta ADC with a built-in PGA and an input multiplexer, in a 28-SSOP surface-mount package. It samples at 480 SPS over SPI, accepting differential or pseudo-differential inputs from up to three or five channels. The analog supply is 5 V; the digital interface runs from 2.7 V to 5.25 V.
480 SPS and 18 bits — the trade-off that matters
The 480 SPS sampling rate is the key constraint. This is not a part for audio or vibration capture — it is a slow, high-resolution converter. At 18 bits with a Sigma-Delta modulator, the output data rate is low by design; the oversampling and digital filtering inside the chip trade speed for noise rejection. If your signal changes faster than a few hundred hertz, you need a different architecture. But for a DC or near-DC sensor bridge, a thermocouple, or a load cell, 480 SPS is plenty and the 18-bit resolution gives you the dynamic range to avoid a separate PGA stage. The internal PGA (feature) lets you amplify small signals before conversion, reducing the external BOM count.
Active lifecycle — no LTB pressure for this BOM line
The MAX1400CAI+ carries an Active lifecycle status. For a sourcing decision, this removes the urgency of a last-time buy or a forced redesign. The part is ROHS3 compliant, so it fits lead-free assembly lines without a waiver. If you are qualifying this into a new design or filling a production BOM, the active status gives you runway; there is no clock ticking on availability from the factory channel.
Package and mounting — 28-SSOP, surface mount
The part comes in a 28-SSOP (0.209", 5.30 mm width) package, surface-mount only. The supplier device package is the same 28-SSOP. No through-hole option exists. The shipping medium is Tube, so if your pick-and-place line expects tape-and-reel, verify the tube-to-reel transfer or order a reel variant if one exists in the family. The 28-SSOP footprint is common; board layout should match the JEDEC standard for this body width.