The TC660 DC-to-DC voltage converter generates a negative voltage supply, that can support a 100mA maximum load, from a positive voltage input of 1.5V to 5.5V. Only two external capacitors are required. Power supply voltage is stored on an undedicated capacitor then inverted and transferred to an output reservoir capacitor. The on-board oscillator normally runs at a frequency of 10kHz with V+ at 5V. This frequency can be lowered by the addition of an external capacitor from OSC (pin 7) to ground, or raised to 90kHz by connecting the frequency control pin (FC) to V+, in order to optimize capacitor size, quiescent current, and output voltage ripple frequency. Operation using input voltage between 1.5V and 3.0V is accommodated by grounding the LV input (pin 6). Operation at higher input voltages (3.0V to 5.5V) is accomplished by leaving LV open. The TC660 open circuit output voltage is within 0.1% of the input voltage with the output open-circuited. Power conversion efficiency is 98% when output load is between 2mA and 5mA.