Wideband precision current sources for integrated circuits

This article introduces two new configurations for precision current sources and current mirrors. Both circuits use n-p-n bipolar devices, but one provides a current source while the other provides a current sink. This permits the use of current sources in IC designs implemented with processes that do not allow p-n-p devices. Analog building blocks such as voltage-to-current converters, active loads, and sink and source current mirrors can be constructed from the new circuits using only n-p-n devices. Furthermore, because these circuits achieve the required precision without the use of high-gain amplifiers, the bandwidths of the circuits are large compared to conventional configurations. The source currents are dependent on a single reference voltage and exhibit good temperature sensitivity.