A simple built-in current sensor for current monitoring in mixed-signal circuits

Quiescent current monitoring is an interesting and efficient technique for mixed-signal testing where fault detection of analog parts requires the precise measure of the I/sub ddq/. This paper presents a very simple current sensor for on-chip current monitoring giving a precise analog output proportional to the quiescent current. Simulations show feasibility of the sensor to operate at high frequencies. This circuit may also operate at low supply voltage (/spl plusmn/1.5 V), and due to its simplicity, the silicon area overhead is very small.