Charge pump for SIM card biasing — 5 V from a 2.7 V–4.2 V input
The Maxim Integrated MAX1686HEUA+ is a single-output charge pump regulator designed to generate a regulated 5 V output from a lithium-ion battery range of 2.7 V to 4.2 V. Its primary application is biasing SIM cards in mobile handsets, modems, and embedded wireless modules where the system rail is 3.3 V or 3.8 V and the SIM requires a clean 5 V supply. The part is rated for the industrial temperature range of -40°C to 85°C, making it suitable for outdoor telecom base stations and automotive telematics units that see temperature extremes.
Package and footprint — 8-pin uMAX/uSOP, 3.00 mm width
The MAX1686HEUA+ is supplied in an 8-TSSOP / 8-MSOP package with a 0.118" (3.00 mm) body width, also referred to as 8-uMAX or 8-uSOP by Maxim. The surface-mount footprint is compact enough for space-constrained PCB layouts in handheld and module designs.
Lifecycle and compliance — active, no EOL concern
It is ROHS3 compliant, which covers the current EU RoHS exemption list. For a charge pump that has been in production for years, the active status means it remains a safe choice for both new designs and ongoing production without the supply-chain risk of a pending discontinuation.