In this paper, we present the design of a new current-controlled oscillator (ICO). The control current of this ICO is in a nano or sub-nano Ampere range and the sensitivity of the frequency of its output voltage to the control current is about 700 MHz per /spl mu/A. The circuit can operate with a low supply voltage, e.g. V/sub DD/ < 1 V when it is implemented with a 0.18-/spl mu/m technology. It requires no bias current, thus have very low power dissipation. The circuit can be easily implemented using a standard digital CMOS technology. Some applications of the proposed ICO, particularly those for A/D conversion, are also described in the paper.