28V input, 1-4 cell Li-Ion charger in a 28-SSOP
The MAX1737EEI+ from Analog Devices (formerly Maxim Integrated) is a standalone constant-current Li-Ion battery charger IC designed to charge 1 to 4 series cells. It accepts a supply voltage up to 28V, making it suitable for applications powered by unregulated wall adapters, automotive 12V rails, or multi-cell battery packs. The device is packaged in a 28-SSOP (0.154", 3.90mm width) for surface-mount assembly and operates over the industrial temperature range of -40°C to 85°C.
Constant-current charging with timer-based termination
This charger uses a constant-current charging algorithm, which is the standard approach for Li-Ion cells up to the voltage regulation threshold. The only programmable feature is a timer, so charge termination is based on timeout rather than current tapers or temperature monitoring. This simplifies the BOM for fixed-capacity battery packs where the charge time is well-characterized, but it means the designer must ensure the timer period matches the cell capacity and charge current to avoid under- or over-charging.
Industrial temperature grade and sourcing posture
Rated for -40°C to 85°C ambient, the MAX1737EEI+ fits outdoor telecom, automotive cabin, industrial instrumentation, and portable medical gear where the charger must survive cold starts and hot enclosures. The part is listed as Active and ROHS3 compliant, meaning it remains a current-production, first-choice design-in for new BOMs.