Ratiometric charge pump for dual-rail generation without an inductor
The Maxim Integrated MAX860ESA+T is a ratiometric charge-pump IC that generates either a positive doubled output (+2Vin) or a negative inverted output (-Vin) from a single input supply. It delivers up to 50 mA, operates from 1.5 V to 5.5 V input, and is packaged in an 8-pin SOIC. The part is rated for industrial temperature range (-40°C to +85°C), making it suitable for outdoor telecom, industrial sensor modules, and battery-powered field instruments that need a clean negative rail for op-amp bias or LCD contrast without a magnetic component.
Selectable switching frequency — ripple vs. capacitor size trade-off
Three internally selectable switching frequencies — 6 kHz, 50 kHz, and 130 kHz — let the designer balance output ripple against external capacitor physical size. At 130 kHz the flying capacitor can be smaller (cost and board area savings), but ripple increases; at 6 kHz ripple is lower but the capacitor value needs to be larger. This is a practical knob for a BOM engineer: pick the frequency that fits the ripple budget of the downstream load without over-specifying the capacitors.
Output polarity: positive or negative — one chip, two rail options
The output configuration is configurable as either positive (2Vin) or negative (-Vin). That means a single 3.3 V rail can produce either +6.6 V or -3.3 V, covering both a higher-voltage bias rail and a negative supply for a dual-rail op-amp circuit. No external inductor, no transformer — just two or three ceramic capacitors and the IC.
Active lifecycle — no LTB pressure
The MAX860ESA+T is listed as Active on the lifecycle record. The part is ROHS3 compliant. For a BOM line that needs a simple charge pump, this is a clean, low-risk sourcing choice.