Ratiometric charge pump — 2V to 5.5V input, 125mA output
The MAX1680ESA+T is a charge-pump DC-DC converter that produces a regulated output of either -Vin or 2Vin from a 2V to 5.5V input rail, delivering up to 125mA. Its ratiometric topology means the output voltage tracks the input as a fixed multiple or inversion — useful when you need a negative rail or a doubled voltage from a single low-voltage supply without a magnetic inductor.
Switching frequency and output configuration
The internal oscillator runs at either 125kHz or 250kHz, selectable via a logic pin — the higher frequency shrinks the external capacitor size at the cost of slightly higher switching losses. Output is fixed-configuration (positive or negative) with no synchronous rectifier, so the efficiency curve peaks in the middle of the load range and drops at very light loads.
Package and board-fit: 8-SOIC
Housed in an 8-SOIC package (0.154" width, 3.90mm body), the MAX1680ESA+T uses a standard footprint that places cleanly on a two-layer board without via-in-pad.