Charge pump in SOT-23-6 — board-fit and output flexibility
The MAX1721EUT+T is a charge-pump DC-DC converter from Analog Devices that generates either a negative rail (-Vin) or a doubled positive rail (2Vin) from a single input between 1.5 V and 5.5 V. The ratiometric topology means the output voltage tracks the input ratio — no external inductor, just two flying capacitors and a reservoir cap. In a SOT-23-6 package, it fits into tight portable designs where board area is the constraint, not the inductor height.
25 mA output — what it can and cannot drive
Rated 25 mA continuous output, this part is sized for low-power analog rails — op-amp supplies, comparator bias, or a small LCD bias generator. It is not a main power rail for a microcontroller or radio; the 25 mA ceiling limits it to auxiliary or signal-chain rails. The switching frequency spans 60 kHz to 200 kHz, so the external capacitors are small (typically 0.22 µF to 1 µF ceramic) but the ripple at the output is higher than a linear regulator would give.
RoHS3 compliant (no exemptions expiring), so it ships unrestricted into EU and UKCA markets. The SOT-23-6 package (SOT-6 supplier device code) is a standard footprint with wide second-source availability — the same pattern is used across the MAX1720/MAX1721 family, making a pin-compatible swap straightforward if a second source is needed.