Active Li-Ion charger with USB input and programmable current
The LTC4085EDE-4#PBF is an active-production single-cell Li-Ion/Polymer battery charger IC from the PowerPath™ series, designed for USB-powered portable devices. It charges a 3.95V battery pack at up to 1.5A, with the charge current set by an external resistor — no firmware handshake needed for the constant-current phase. The 5.5V max supply voltage covers standard USB bus power (5V nominal) with margin for cable drop and connector resistance. The part operates across the full -40°C to 85°C industrial temperature range, so it suits outdoor handhelds or gear that sees a hot dashboard in summer.
14-DFN package and board-level fit
Housed in a 14-lead WFDFN with exposed pad (4x3 mm body), the LTC4085EDE-4#PBF uses the pad as the primary thermal path. The PCB layout needs a thermal via array under the pad to pull heat into the ground plane — without it the 1.5A charge current pushes the die temperature above the 85°C ambient ceiling on a two-layer board. The surface-mount DFN footprint is common for portable designs; the 0.5 mm pitch and exposed pad are standard for reflow assembly. No special stencil aperture beyond the usual 50-60% paste coverage on the pad.
Sourcing and compliance status
Marked as Active by Analog Devices with RoHS3 compliance.