ECG front end in a hand-solderable QFN
The MAX30003CTI+ is a single-chip ECG front end from Analog Devices, purpose-built for heart-rate monitoring — not a general-purpose microcontroller, but a precision analog front end that conditions and digitises the biopotential signal from electrodes. It comes in a 28-WFQFN with exposed pad (also listed as 28-TQFN, 5x5 mm), a package that is hand-solderable with a hot-air station or reflow oven — the exposed pad needs a good thermal via pattern under it to pull heat away from the die.
What the package means for your board
The 28-WFQFN exposed pad demands a solid thermal land on the PCB — the datasheet's recommended footprint includes a central pad connected to ground with multiple vias to the inner planes. Without that, the die overheats and the analog performance drifts. Surface-mount assembly is standard reflow; the 5x5 mm body is small enough for a compact wearable but large enough to route two layers if you keep the traces short to the decoupling caps.
Sourcing and compliance at a glance
ROHS3 compliance covers the EU RoHS exemption list through 2024; the part is also free of the six original restricted substances plus the four phthalates.